Diagnostic device and diagnostic method

Abstract

To enable easy determination of whether the excitation error after calibration is smaller than the target value. [Solution] The power calculation unit 10 calculates the received power when a signal is received by a reference element system, which is an antenna element system selected from a plurality of antenna element systems, each containing an antenna element, as the reference element power, and calculates the received power when a signal is received by a plurality of antenna element systems, including the reference element system, as the diagnostic power. The threshold calculation unit 13 uses the reference element power and the excitation error target value, which is the target value of the excitation error between antenna element systems, to calculate the upper and lower threshold values ​​of the diagnostic power. The determination unit 14 determines whether the diagnostic power is within the range of the upper and lower threshold values.

Description

[Technical Field]

[0001] This disclosure relates to the diagnosis of array antennas. For example, this disclosure relates to diagnosing the operating state of an array antenna, i.e., whether the error in the pass-through characteristics of each antenna element system meets a predetermined target value. [Background technology]

[0002] Array antennas, composed of multiple antenna elements, are widely used in radar, communication systems, and other applications. In recent years, array antennas with a function called DBF (Digital Beam Forming) (hereinafter referred to as DBF antennas) have become popular. DBF antennas are also beginning to be used in antennas mounted on artificial satellites. In DBF antennas, the high-frequency signals received by each antenna element are converted into digital signals on an element-by-element basis, enabling advanced beamforming and signal multiplexing. Furthermore, when each antenna element transmits a high-frequency signal, the signal is converted from a digital signal to a high-frequency signal on an element-by-element basis.

[0003] In a receiving DBF antenna, the high-frequency signals received by each antenna element are generally amplified by a low-noise amplifier. The amplified high-frequency signals are then frequency-converted to the intermediate frequency band by a frequency converter. Furthermore, the frequency-converted signals are converted into digital signals by an analog-to-digital converter (hereinafter referred to as an AD converter). These digital signals are then input to a DBF signal processing unit that performs predetermined beamforming and other operations through digital signal processing. The DBF signal processing unit multiplies the signal from each antenna element by the excitation coefficient required to form the desired beam, for example. Furthermore, the DBF signal processing unit synthesizes the signals from all antenna elements and outputs the resulting combined signal as the output signal.

[0004] Incidentally, in order to achieve the desired beamformation in the DBF signal processing unit, the amplitude difference and phase difference of the high-frequency signals arriving at each antenna element must be preserved in the digital signal, i.e., in the baseband band. Generally, there are individual differences between each antenna element, and between the low-noise amplifiers, frequency converters, AD converters connected to each antenna element, and the input / output lines connecting them (hereinafter collectively referred to as the antenna element system). As a result, each antenna element system has different electrical characteristics. This causes amplitude differences and phase differences (errors) between each antenna element system, and as a result, the desired beamformation becomes impossible.

[0005] In response to this, a method is employed in which the received digital signal of each antenna element is multiplied by a predetermined calibration value to reduce the influence of errors between antenna element systems. For example, in the DBF antenna mounted on an artificial satellite as described in Patent Document 1, the autocorrelation value / cross-correlation value is calculated in the digital signal domain from the received signals of each antenna element to the calibration high-frequency signal transmitted from a ground communication device used for calibration (hereinafter referred to as the calibration station). Then, information regarding this correlation value is transmitted as a telemetry signal to another ground communication device (hereinafter referred to as the ground station). Furthermore, in the calibration system connected to the ground station, a calibration value is determined based on the received correlation value information, the amplitude and phase values ​​of the radiation patterns of each antenna element of the DBF antenna, and the direction of the calibration station as seen from the DBF antenna. Then, the DBF antenna is calibrated using the determined calibration value. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. WO2021 / 152660 [Overview of the project] [Problems that the invention aims to solve]

[0007] Errors between antenna elements fluctuate with changes in ambient temperature, etc. Therefore, it is desirable to calibrate DBF antennas even while they are in operation. However, calibration measurements, i.e., the transmission and reception of calibration high-frequency signals, must be performed at times when actual communications are not taking place, in order to avoid interference with communications, which are the primary purpose of the DBF antenna. Therefore, if calibration is to be performed while the DBF antenna is in operation, it is necessary to interrupt actual communications, i.e., satellite services. Normally, DBF antennas are calibrated periodically during operation, or based on instructions from the higher-level system or its operations manager. However, in all cases, even when there is no error variation between antenna element systems, or the variation is sufficiently small that calibration is not actually necessary, measurements for calibration may still be performed. This results in the problem of unnecessary service interruptions.

[0008] Furthermore, the calibration values ​​obtained by the method described in Patent Document 1 have errors (hereinafter referred to as calibration errors) compared to the ideal calibration values ​​due to factors such as thermal noise and attitude errors in satellite values. In particular, if the signal-to-noise ratio of the high-frequency signal used for calibration decreases due to increased rainfall attenuation, the calibration error will increase. As a result, calibration may actually degrade the antenna performance, such as the beam shape and gain of the DBF antenna.

[0009] To prevent these unnecessary service interruptions and degradation of antenna performance due to calibration, a technique is needed to determine, in a simple manner, whether the amplitude error and phase error (difference from the desired signal, hereinafter collectively referred to as excitation error) of the signal of each antenna element after calibration are smaller than the separately defined target value of excitation error.

[0010] In light of these circumstances, the main purpose of this disclosure is to enable a simple determination of whether or not the excitation error after calibration is smaller than the target value. [Means for solving the problem]

[0011] The diagnostic device related to this disclosure is A power calculation unit calculates either the received power when a signal is received by a reference element system, which is an antenna element system selected from a plurality of antenna element systems, each containing an antenna element, or the received power when a signal transmitted from the reference element system is received, as the reference element power, and calculates either the received power when a signal is received by the plurality of antenna element systems including the reference element system or the received power when a signal transmitted from the plurality of antenna element systems including the reference element system is received, as the diagnostic power. A threshold calculation unit calculates an upper and lower threshold for the diagnostic power using the reference element power and an excitation error target value, which is a target value for the excitation error between antenna element systems. The system includes a determination unit that determines whether the diagnostic power is within the range of the upper limit threshold and the lower limit threshold. [Effects of the Invention]

[0012] According to this disclosure, it is possible to easily determine whether the excitation error after calibration is smaller than the target value. [Brief explanation of the drawing]

[0013] [Figure 1] A block diagram showing an example configuration of the array antenna diagnostic system according to Embodiment 1. [Figure 2] A flowchart showing an example of an array antenna diagnostic procedure according to Embodiment 1. [Figure 3] A block diagram showing an example configuration of an array antenna diagnostic system according to Embodiment 2. [Figure 4] A flowchart showing an example of an array antenna diagnostic procedure according to Embodiment 2. [Figure 5] A block diagram showing an example configuration of an array antenna diagnostic system according to Embodiment 3. [Figure 6] A flowchart showing an example of an array antenna diagnostic procedure according to Embodiment 3. [Figure 7] A block diagram showing an example configuration of an array antenna diagnostic system according to Embodiment 4. [Figure 8] A flowchart showing an example of an array antenna diagnostic procedure according to Embodiment 4. [Figure 9] A block diagram showing an example configuration of an array antenna diagnostic system according to Embodiment 5. [Figure 10] A flowchart showing an example of an array antenna diagnostic procedure according to Embodiment 5. [Figure 11] A block diagram showing an example configuration of an array antenna diagnostic system according to Embodiment 6. [Figure 12] A flowchart showing an example of an array antenna diagnostic procedure according to Embodiment 6. [Figure 13] A block diagram showing an example of the hardware configuration of a diagnostic device according to Embodiments 1 to 6. [Modes for carrying out the invention]

[0014] The embodiments will be described below with reference to the drawings. In the following description of the embodiments and in the drawings, the same reference numerals indicate the same part or a corresponding part.

[0015] Embodiment 1. ****Configuration Description***

[0016] Figure 1 shows an example of the configuration of an array antenna diagnostic system according to Embodiment 1. The array antenna diagnostic system according to Embodiment 1 consists of an array antenna 1 and a diagnostic antenna device 7.

[0017] Array antenna 1 is the DBF antenna being diagnosed. The array antenna 1 consists of antenna elements 2-1 to 2-M, receivers 3-1 to 3-M, a received DBF signal processing unit 4, an excitation coefficient storage unit 5, an output terminal 6, a power calculation unit 10, an excitation error target value storage unit 11, an element electric field value storage unit 12, a threshold calculation unit 13, and a determination unit 14. The "M" in antenna element 2-M and receiver 3-M indicates the number of antenna elements. That is, array antenna 1 in Figure 1 contains M antenna elements and M receivers. Furthermore, antenna element numbers are denoted by "m". That is, in the following, antenna elements 2-1 to 2-M will be collectively referred to as antenna element 2-m. Similarly, receivers 3-1 to 3-M will be collectively referred to as receiver 3-m.

[0018] The diagnostic antenna device 7 generates a high-frequency signal for diagnostic purposes and transmits the generated high-frequency signal. The diagnostic antenna device 7 consists of a diagnostic antenna 8 and a diagnostic signal generation circuit 9.

[0019] In array antenna 1, antenna elements 2-1 to 2-M are radiating elements that receive high-frequency signals.

[0020] Receivers 3-1 to 3-M amplify the high-frequency signals received by antenna elements 2-1 to 2-M. Receivers 3-1 to 3-M also convert the frequency of the amplified high-frequency signals to an intermediate frequency band. Furthermore, receivers 3-1 to 3-M convert the frequency-converted analog signals to digital signals. Receivers 3-1 to 3-M are composed of components such as a low-noise amplifier, a frequency conversion circuit, an analog-to-digital conversion circuit, and a filter circuit.

[0021] In this embodiment, the antenna element 2-m, the receiver 3-m, and the connecting wires between them are collectively referred to as the antenna element system m. Furthermore, in this embodiment, antenna element 2-1 is selected from antenna elements 2-1 to 2-M as a reference element to serve as the basis for diagnosis. Hereinafter, antenna element 2-1 will also be referred to as the reference element. The antenna element system consisting of antenna element 2-1, receiver 3-1, and the connecting wires between them will also be referred to as the reference element system.

[0022] The received DBF signal processing unit 4 performs so-called DBF signal processing on the received signals from antenna elements 2-1 to 2-M output by receivers 3-1 to 3-M. The received DBF signal processing unit 4 is configured, for example, by a digital circuit. The received DBF signal processing unit 4 multiplies the excitation coefficients stored in the excitation coefficient storage unit 5 by the respective received signals of antenna elements 2-1 to 2-M. Then, the received DBF signal processing unit 4 adds the multiplied received signals together.

[0023] The excitation coefficient storage unit 5 stores the excitation coefficients for forming a predetermined beam pattern. As described above, the excitation coefficients stored in the excitation coefficient storage unit 5 are multiplied by the received signals of antenna elements 2-1 to 2-M by the received DBF signal processing unit 4. The received DBF signal processing unit 4 multiplies the excitation coefficients by the received signals of antenna elements 2-1 to 2-M to form a predetermined beam pattern.

[0024] The excitation coefficient storage unit 5 stores not only the nominal values ​​of various excitation coefficients necessary for the actual operation of the array antenna 1 to be diagnosed, but also the nominal values ​​of the excitation coefficient for reference element evaluation and the nominal values ​​of the excitation coefficient for evaluation beam. The excitation coefficient for evaluating the reference element is the excitation coefficient used to calculate the reference element power, as described later. It is an excitation coefficient that assigns a weight of 1 to the reference element and 0 to other antenna elements. The nominal value of the excitation coefficient for the evaluation beam is the nominal value of the excitation coefficient used to calculate the upper and lower threshold values ​​of the evaluation beam power, as described later. Furthermore, the excitation coefficient storage unit 5 also stores the calibrated excitation coefficient for the evaluation beam. The calibrated excitation coefficient for the evaluation beam is obtained by multiplying the nominal value of the evaluation beam excitation coefficient by a calibration value that is stored separately to correct for errors in the transmission characteristics of each antenna element system m.

[0025] Output terminal 6 is a terminal that outputs the output signal from the received DBF signal processing unit 4.

[0026] In the diagnostic antenna device 7, the diagnostic antenna 8 transmits a high-frequency signal used for diagnosis. The diagnostic antenna 8 is installed at a known location that allows it to transmit a high-frequency signal to the array antenna 1 being diagnosed. Therefore, the distance R between the array antenna 1 and the diagnostic antenna 8 is R > 2 × D 2 A diagnostic antenna 8 may be installed at a position that satisfies the condition / λ and can be considered to be in the so-called far-field of the radio waves received by array antenna 1. Here, D is the aperture diameter of array antenna 1 and λ is the wavelength of the high-frequency signal. Conversely, a diagnostic antenna 8 may be installed at a position adjacent to array antenna 1. The diagnostic antenna 8 is an antenna located outside of array antenna 1 and corresponds to an external antenna.

[0027] The diagnostic signal generation circuit 9 generates a high-frequency signal for diagnostic purposes. The diagnostic signal generation circuit 9 is a signal source that generates, for example, a continuous wave or various modulated waves. The diagnostic signal generation circuit 9 is composed of, for example, a circuit combining an oscillator, a synthesizer circuit, a modulation circuit, a frequency mixer, and an amplifier. The high-frequency signal used for diagnosis may be a known high-frequency signal generated for diagnostic purposes. Alternatively, the high-frequency signal used for diagnosis may be a communication signal used by the array antenna 1 during actual operation.

[0028] In the array antenna 1, the power calculation unit 10 calculates the reference element power and the evaluation beam power. The reference element power is the received power when the high-frequency signal from the diagnostic antenna device 7 is received by the reference element system (antenna element 2-1 and receiver 3-1). The evaluation beam power is the received power when the high-frequency signal from the diagnostic antenna device 7 is received by multiple antenna element systems m, including a reference element system. The evaluation beam power corresponds to the diagnostic power. More specifically, the power calculation unit 10 multiplies the digital signal output from receiver 3-m by the excitation coefficient for reference element evaluation stored in the excitation coefficient storage unit 5. Furthermore, the power calculation unit 10 synthesizes the digital signal from receiver 3-m after multiplying by the excitation coefficient for reference element evaluation. Finally, the power calculation unit 10 calculates the reference element power by squaring the absolute value of the signal obtained by synthesis, i.e., the digital signal output from receiver 3-1 included in the reference element system. Furthermore, the power calculation unit 10 multiplies the digital signal output from the receiver 3-m by the calibrated excitation coefficient for the evaluation beam stored in the excitation coefficient storage unit 5. The power calculation unit 10 then synthesizes the digital signal from the receiver 3-m after multiplying by the calibrated excitation coefficient for the evaluation beam. Finally, the power calculation unit 10 calculates the evaluation beam power by squaring the absolute value of the signal obtained through synthesis.

[0029] The excitation error target value storage unit 11 stores the excitation error target value. The excitation error target value is the target value for the operating state of array antenna 1 being diagnosed. More specifically, the excitation error target value is the target value for the excitation error between the antenna element systems. The excitation error target value storage unit 11 stores, for example, the standard deviations of the amplitude error and phase error of the signals between antenna element systems as excitation error target values. The excitation error target value storage unit 11 may also store the variances of the amplitude error and phase error of the signals between antenna element systems as excitation error target values. Furthermore, the excitation error target value storage unit 11 may also store the variance of the combined error, which is the sum of the amplitude error and phase error of the signals between antenna element systems, as excitation error target values.

[0030] The element electric field value storage unit 12 stores the element electric field value. The element field value is a pass-through characteristic value that represents the pass-through characteristics between each of the antenna elements 2-1 to 2-M and the diagnostic antenna 8. The element field value storage unit 12 stores the amplitude and phase values ​​of the element field values. Specifically, the element field value storage unit 12 stores the theoretical values ​​of the pass characteristics between each of the antenna elements 2-1 to 2-M and the diagnostic antenna 8 as the amplitude and phase values ​​of the element field values. Alternatively, the element field value storage unit 12 may store the calculated values ​​of the pass characteristics between each of the antenna elements 2-1 to 2-M and the diagnostic antenna 8 as the amplitude and phase values ​​of the element field values. Furthermore, the element field value storage unit 12 may store the measured values ​​of the pass characteristics between each of the antenna elements 2-1 to 2-M and the diagnostic antenna 8 as the amplitude and phase values ​​of the element field values. If the diagnostic antenna 8 is installed opposite the array antenna 1 and in a position that can be considered as the so-called far-field of the array antenna 1, the element electric field value may be any of the theoretical, calculated, or measured values ​​of the amplitude and phase values ​​of the far-field radiation pattern of each antenna element 2-1 to 2-M in the direction of the diagnostic antenna 8 as seen from the array antenna 1. The far-field radiation pattern can be calculated using a function of the azimuth defined in a default coordinate system and information about the direction of a known diagnostic antenna 8. Alternatively, the far-field radiation pattern may be calculated using amplitude and phase values ​​in multiple sample directions set in a grid on the default coordinate system and information about the direction of a known diagnostic antenna 8. When a far-field radiation pattern is calculated, the element electric field value storage unit 12 may store the aforementioned function or the amplitude and phase values ​​in multiple sample directions.

[0031] The threshold calculation unit 13 calculates the upper and lower thresholds for the evaluation beam power (diagnostic power). The upper and lower thresholds for the evaluation beam power are collectively called the received power threshold. The threshold calculation unit 13 calculates the upper and lower threshold values ​​for the evaluation beam power using the nominal value of the excitation coefficient for the evaluation beam, the reference element power, the target excitation error value, and the element electric field values ​​of each of the antenna elements 2-1 to 2-M. As mentioned above, the nominal value of the excitation coefficient for the evaluation beam is stored in the excitation coefficient storage unit 5. The reference element power is calculated by the power calculation unit 10. The excitation error target value is stored in the excitation error target value storage unit 11. The element electric field value of each antenna element 2-1 to 2-M is stored in the element electric field value storage unit 12.

[0032] The determination unit 14 determines whether the evaluation beam power is within the range of the upper and lower thresholds. As described above, the evaluation beam power is calculated by the power calculation unit 10. The upper and lower thresholds are calculated by the threshold calculation unit 13. The determination unit 14 determines that the excitation error between antenna element systems is smaller than the excitation error target value when the evaluated beam power is within the range of the upper and lower threshold values. In other words, the determination unit 14 can determine whether the excitation error of the signal of each antenna element after calibration is smaller than the excitation error target value. The determination unit 14 outputs a determination result, that is, a determination result of whether or not the excitation error is smaller than the excitation error target value.

[0033] The power calculation unit 10, threshold calculation unit 13, and determination unit 14 are also referred to as the diagnostic device 100. The diagnostic device 100 is implemented, for example, by a computer.

[0034] ***Explanation of operation*** Next, an example of the operation of the array antenna diagnostic system according to Embodiment 1 will be explained using Figure 2. Figure 2 is a flowchart showing an example of the operation of the array antenna diagnostic system according to Embodiment 1.

[0035] First, in step ST1-1, a diagnostic high-frequency signal is sent from the diagnostic antenna device 7 to the array antenna 1. Specifically, the diagnostic signal generation circuit 9 generates a high-frequency signal, either as a diagnostic high-frequency signal or as a communication signal for normal communication. Then, the diagnostic antenna 8 radiates the generated high-frequency signal into space. As a result, a high-frequency signal is transmitted towards the array antenna 1.

[0036] In step ST1-2, the transmitted high-frequency signal is received by each of the antenna elements 2-1 to 2-M of the array antenna 1. Then, each of the receivers 3-1 to 3-M amplifies the received high-frequency signal and frequency-converts the amplified high-frequency signal to an intermediate frequency band. Further, each of the receivers 3-1 to 3-M converts the frequency-converted analog signal into a digital signal and acquires the converted digital signal as a received signal.

[0037] Here, the high-frequency signal transmitted by the diagnostic antenna device 7 is expressed as s. Also, the transmission characteristics between the diagnostic antenna 8 and each antenna element 2-m of the array antenna 1, that is, the element electric field value, is E m which is expressed as such. Note that the element electric field value E m is stored in the element electric field value storage unit 12. At this time, the high-frequency signal x m transmitted by the diagnostic antenna device 7 and received by each antenna element 2-m m can be expressed as x [[ID==13]] m = E s. In step ST1-2, the receiver 3-m amplifies this high-frequency signal x m and frequency-converts the amplified high-frequency signal xm to an intermediate frequency band. Further, the receiver 3-m converts the frequency-converted analog signal into a digital signal. The complex digital signal X m output by each receiver 3-m m can be expressed as X m = A m E m s + N m where N m is a thermal noise component. Also, A d is the transmission characteristic value of the receiver 3-m.

[0038] In step ST1-3, the power calculation unit 10 calculates the reference element power P1 and the evaluation beam power P d . As described above, the reference element power P1 is the received power when the high-frequency signal from the diagnostic antenna device 7 is received by the reference element system. The evaluation beam power P d is the received power when the high-frequency signal from the diagnostic antenna device 7 is received by a plurality of antenna element systems including the reference element system.

[0039] The power calculation unit 10 calculates the reference element power P1 using the complex digital signal X1 = A1E1s + N1 output by the receiver 3-1. The reference element power P1 is the square of the absolute value of the complex digital signal X1. Specifically, the power calculation unit 10 calculates the reference element power P1 according to Equation 1.

[0040]

number

[0041] Next, evaluate the beam power P. d Let's consider this. The evaluation beam receives each received signal X m Multiply each received signal X by an appropriate excitation coefficient. m The signal obtained by synthesizing these signals is used. Passage characteristic value A m This varies every 3 meters of the receiver. Therefore, typically, the pass-through characteristic value A m DBF signal processing is performed after calibration to ensure that the influence on the communication signal is equal across all receivers 3-m. In the case of the evaluation beam, the received signal X is processed in the same way as in the case of the communication signal. m Calibration is performed, and the received signal X after calibration is then... m Synthesize them. In this embodiment, the pass-through characteristic value A for each of the antenna elements 2-m m The calibration value is determined so that the influence is canceled out and all antenna elements 2-m are equally affected by the transmission characteristic A1 of the reference element (antenna element 2-1). That is, the ideal calibration value C for each received signal of antenna element 2-m is determined. m C m =A1 / A m The following relationship is satisfied. On the other hand, the passing characteristic value A m This is an unknown component. Therefore, in this embodiment, the pass-through characteristic value A is determined by some other means / method. m The value of is measured or estimated. Then, the measured or estimated pass-through characteristic value A m The ratio of the pass-through characteristic value A1 to the calibration value C mIt is used as '. That is, the excitation coefficient storage unit 5 stores the nominal value W of the excitation coefficient for the evaluation beam. m In addition, the nominal value W m Calibration value C m The calibrated excitation coefficient W obtained by multiplying by ' m C m ' is remembered. Evaluation beam power P d Each received signal X m Calibrated excitation coefficient W m C m It is obtained by multiplying by ', synthesizing the multiplied signals, and squaring the absolute value of the synthesized signals. Specifically, the power calculation unit 10 evaluates the beam power P according to equation 2. d Calculate.

[0042]

number

[0043] In equation 2 and the following equations, Σc m is a complex number c m This is an operator that calculates the sum of m from m=1 to M.

[0044] Next, in step ST1-4, the threshold calculation unit 13 calculates the nominal value W of the excitation coefficient for the evaluation beam. m and reference element power P1 and element electric field value E m Using the excitation error target value, evaluate the beam power P d Calculate the upper and lower threshold values. Nominal value W for excitation coefficient for evaluation beam m As mentioned above, this is stored in the excitation coefficient storage unit 5. Also, the reference element power P1 is calculated in step ST1-3. Element electric field value E m The element electric field value is stored in the element electric field value storage unit 12. The excitation error target is stored in the excitation error target value storage unit 11.

[0045] Calibration value C obtained by measurement m ' is the ideal calibration value C due to the influence of thermal noise, etc. m This value has an error relative to Δ. Here, the amplitude error is Δm And the phase error is δ m Let's assume that the calibration value is C. m 'and the ideal calibration value C m C m '=C m (1+Δ m )exp(jδ m Assume that the following relationship exists, where j is the imaginary unit and exp() represents the exponential function. In this case, if the high-frequency signal component for diagnosis or communication among the signal components of the evaluation beam is sufficiently large compared to the thermal noise component, then neglecting the thermal noise component, the evaluation beam power P d The approximate value of is expressed as shown in Equation 3.

[0046]

number

[0047] As can be seen from Equation 3, the evaluation beam power P d The amplitude error is Δ m , phase error δ m It changes depending on the magnitude. Therefore, the evaluation beam power P generated by the expected maximum amplitude error and phase error. d Evaluate the maximum and minimum values ​​of the variation in beam power P. d These can be used as the upper and lower threshold limits. Therefore, the threshold calculation unit 13 calculates, for example, the amplitude error Δ within the range of the expected maximum amplitude error and phase error. m and phase error δ m The parameters are set randomly, and equation 3 is calculated many times as a trial. Then, the threshold calculation unit 13 evaluates the beam power P from the results of the trial calculations. d The maximum and minimum values ​​are obtained. The threshold calculation unit 13 evaluates the beam power P using the maximum value. d Select the upper threshold value and evaluate the minimum value of beam power P. d Select this as the lower threshold. Furthermore, the threshold calculation unit 13 statistically evaluates equation 3 and evaluates the beam power P d The maximum and minimum values ​​may also be obtained. In this case as well, the threshold calculation unit 13 evaluates the beam power P using the maximum value. dSelect the upper threshold value and evaluate the minimum value of beam power P. d Select this as the lower threshold.

[0048] Equation 3 is the excitation coefficient W m E m So, the amplitude error Δ m and phase error δ m This can be seen as a constant multiple of the square of the amplitude F of the composite electric field of an array antenna having an omnidirectional antenna element pattern. Here, the nominal value W of the excitation coefficient for forming the evaluation beam. m Assume that it is set to satisfy equation 4.

[0049]

number

[0050] However, α m is a suitable real constant. The excitation coefficient W is given by Equation 4. m This is the high-frequency signal x received by each of the antenna elements 2-m when there is no excitation error. m This corresponds to the excitation coefficient when these are combined in phase. In this case, the amplitude F0 of the composite electric field when there is no amplitude error or phase error is equal to the amplitude error Δ m and phase error δ m It becomes sufficiently large compared to the error electric field component caused by the above. The amplitude F of the combined electric field has an average value F0 given by equation 5 and a variance σ given by equations 6 and 7. 2 It will begin to follow a normal distribution.

[0051]

number

[0052]

number

[0053]

number

[0054] However, σ Δ 2 = E[Δ m 2 , σ δ 2 = E[δ m 2 , and E[β m is an operator indicating the average value of β m . σ Δ 2 indicates the variance of the amplitude error, and σ δ 2 indicates the variance of the phase error. Therefore, it is considered that the synthetic electric field amplitude F is within the range of F0 - 3σ to F0 + 3σ with a probability of 99.7%. Thus, in this embodiment, the threshold calculation unit 13 determines the upper limit threshold P d of the evaluation beam power P max as shown in Equation 8. Also, the threshold calculation unit 13 determines the lower limit threshold P d of the evaluation beam power P min as shown in Equation 9.

[0055]

Equation

[0056]

Equation

[0057] From the above, in step ST1 - 4, the threshold calculation unit 13 uses the nominal value W m of the excitation coefficient for the evaluation beam that satisfies Equation 4, the reference element power P1, the element electric field value E m , and the excitation error target value to calculate the upper limit threshold P d and the lower limit threshold P max of the evaluation beam power P min according to Equations 4 to 9. Note that the excitation error target value is the variance σ Δ 2 of the amplitude error and the variance σ δ 2 of the phase error, or the sum σ Δ 2 + σδ 2 That is the case.

[0058] In step ST1-5, the determination unit 14 evaluates the beam power P d and upper threshold P max and lower threshold P min The two are compared and evaluated. That is, the determination unit 14 evaluates the beam power P d The upper threshold P max and lower threshold P min Determine if it is within the range. P min ≤P d ≤P max If this is the case, the determination unit 14 determines that the excitation error of each signal of the calibrated antenna element 2-m is smaller than the excitation error target value. On the other hand, P d <P min or P d >P max If so, the determination unit 14 determines that the excitation error of each signal of the calibrated antenna element 2-m is greater than the target excitation error value.

[0059] ***Explanation of the effects of the embodiment*** According to this embodiment, it is possible to easily determine whether the excitation error after calibration is smaller than the target value.

[0060] Specifically, in the array antenna diagnostic system according to Embodiment 1, the reference element power and evaluation beam power of the DBF antenna are calculated based on a diagnostic signal transmitted from the diagnostic antenna, using a pre-stored excitation coefficient for reference element evaluation and a calibrated excitation coefficient for the evaluation beam. Furthermore, the received power threshold of the evaluation beam is calculated using the reference element power, a pre-stored excitation coefficient for the evaluation beam before calibration, a pre-stored element electric field value which is the pass-through characteristic between each antenna element and the diagnostic antenna, and a pre-stored excitation error target value. Then, it is evaluated whether the evaluation beam power is within the range defined by the received power threshold. As a result, it is possible to determine whether the excitation error of the signal of each antenna element after calibration is smaller than the excitation error target value.

[0061] Furthermore, based on this judgment, calibration measurements of the DBF antenna only need to be performed if it is determined that the excitation error of the signal of each antenna element after calibration is greater than the target excitation error value. This prevents the performance of calibration measurements when calibration is not necessary, and as a result, unnecessary service interruptions can be prevented. In addition, by performing calibration measurements until the excitation error of the signal of each antenna element after calibration becomes smaller than the above target excitation error value, it is possible to prevent deterioration of antenna performance due to calibration.

[0062] Embodiment 2. Embodiment 1 described an example in which an array antenna receives a high-frequency signal from a diagnostic antenna device. This embodiment describes an example in which an array antenna transmits a high-frequency signal to a diagnostic antenna device. This embodiment will primarily describe the differences from Embodiment 1. Matters not described below are the same as in Embodiment 1.

[0063] ***Explanation of the structure*** Figure 3 shows an example of the configuration of an array antenna diagnostic system according to Embodiment 2. The array antenna diagnostic system according to Embodiment 2 consists of an array antenna 20 and a diagnostic antenna device 24.

[0064] Array antenna 20 is the DBF antenna being diagnosed. However, array antenna 20 is a transmitting DBF antenna. The array antenna 20 consists of antenna elements 2-1 to 2-M, transmitters 21-1 to 21-M, a transmit DBF signal processing unit 22, an excitation coefficient storage unit 5, and an input terminal 23. Note that the "M" in antenna element 2-M and transmitter 21-M indicates the number of antenna elements. In other words, the array antenna 20 in Figure 3 contains M antenna elements and M transmitters. Furthermore, antenna element numbers are denoted by "m". That is, in the following, antenna elements 2-1 to 2-M will be collectively referred to as antenna element 2-m. Similarly, transmitters 21-1 to 21-M will be collectively referred to as transmitter 21-m.

[0065] The diagnostic antenna device 24 receives a high-frequency signal for diagnosis and uses the received high-frequency signal to evaluate the excitation error. The diagnostic antenna device 24 consists of a diagnostic antenna 8, a receiver 25, a power calculation unit 26, an excitation error target value storage unit 11, an element electric field value storage unit 12, a second excitation coefficient storage unit 27, a threshold calculation unit 28, and a determination unit 29.

[0066] Note that in Figure 2, the same reference numerals are used for components identical to those in Figure 1. Explanations for components identical to those in Figure 1 are omitted.

[0067] In the array antenna 20, transmitters 21-1 to 21-M convert the diagnostic signals for each antenna element 2-m output by the transmitting DBF signal processing unit 22 into analog signals. Transmitters 21-1 to 21-M also convert the frequency of the converted analog signals to a high-frequency band. Furthermore, transmitters 21-1 to 21-M amplify the frequency-converted high-frequency signals and input them to the antenna elements 2-1 to 2-M. Transmitters 21-1 to 21-M are composed of, for example, a high-power amplifier, a frequency conversion circuit, a digital-to-analog conversion circuit, a filter circuit, etc.

[0068] In this embodiment, the antenna element 2-m, the transmitter 21-m, and the connecting wires between them are collectively referred to as the antenna element system m. Furthermore, in this embodiment, antenna element 2-1 is selected from antenna elements 2-1 to 2-M as a reference element to serve as the basis for diagnosis. Hereafter, antenna element 2-1 will also be referred to as the reference element. The antenna element system consisting of antenna element 2-1 and transmitter 21-1 will also be referred to as the reference element system.

[0069] The transmission DBF signal processing unit 22 performs so-called DBF signal processing on the digital signal input from the input terminal 23, and generates a diagnostic signal to be output to each of the transmitters 21-1 to 21-M. The transmission DBF signal processing unit 22, for example, duplicates the digital signal input from the input terminal 23 by the number of antenna elements. Then, the transmission DBF signal processing unit 22 multiplies each of the duplicated signals by the excitation coefficient stored in the excitation coefficient storage unit 5. Further, the transmission DBF signal processing unit 22 outputs the multiplied signals to each of the transmitters 21-1 to 21-M.

[0070] The input terminal 23 is a terminal for inputting a diagnostic digital signal transmitted from the array antenna 20 to the transmission DBF signal processing unit 22. The signal input from the input terminal 23 to the transmission DBF signal processing unit 22 may be a known signal generated only for diagnosis, or may be a communication signal used during the actual operation of the array antenna 20.

[0071] In the present embodiment, the diagnostic antenna 8 of the diagnostic antenna device 24 receives a high-frequency signal used for diagnosis.

[0072] The receiver 25 amplifies the high-frequency signal input from the diagnostic antenna 8. In addition, the receiver 25 converts the frequency of the amplified signal into an intermediate frequency band and converts the frequency-converted analog signal into a digital signal. The receiver 25 is composed of, for example, a low-noise amplifier, a frequency conversion circuit, an analog-to-digital conversion circuit, a filter circuit, etc.

[0073] The power calculation unit 26 calculates the reference element power and the evaluation beam power. In the present embodiment, the reference element power is the received power when the high-frequency signal transmitted from the reference element system (antenna element 2-1 and transmitter 21-1) is received by the diagnostic antenna device 24. In the present embodiment, the evaluation beam power is the received power when the high-frequency signal transmitted from a plurality of antenna element systems m including the reference element system is received by the diagnostic antenna device 7. The evaluation beam power corresponds to the diagnostic power. More specifically, the power calculation unit 26 calculates the reference element power by squaring the absolute value of the digital signal output from the receiver 25 obtained from the received signal from the reference element system. The power calculation unit 26 stores the calculated reference element power. Also, the power calculation unit 26 may store the calculated reference element power in a predetermined storage area. In this embodiment, it is assumed that the power calculation unit 26 stores the reference element power.

[0074] Further, the power calculation unit 26 multiplies the digital signal output from the receiver 25 obtained from the received signal from each of the antenna element systems m by the calibrated excitation coefficient for the evaluation beam stored in the second excitation coefficient storage unit 27. Furthermore, the power calculation unit 26 synthesizes the m digital signals after multiplying them by the calibrated excitation coefficient for the evaluation beam. Furthermore, the power calculation unit 26 calculates the evaluation beam power by squaring the absolute value of the signal obtained by the synthesis. The power calculation unit 26 stores the calculated evaluation beam power. Also, the power calculation unit 26 may store the calculated evaluation beam power in a predetermined storage area. In this embodiment, it is assumed that the power calculation unit 26 stores the evaluation beam power.

[0075] The second excitation coefficient storage unit 27 stores the same excitation coefficients as those stored in the excitation coefficient storage unit 5. <8000907>

[0076] The threshold calculation unit 28 calculates the upper limit threshold and the lower limit threshold of the evaluation beam power (diagnostic power). More specifically, the threshold calculation unit 28 calculates the upper limit threshold and the lower limit threshold of the evaluation beam power by using the nominal value of the excitation coefficient for the evaluation beam, the reference element power, the excitation error target value, and the element electric field values of each of the antenna elements 2-1 to 2-M. The nominal value of the excitation coefficient for the evaluation beam is stored in the second excitation coefficient storage unit 27. The reference element power is calculated by the power calculation unit 26. The excitation error target value is stored in the excitation error target value storage unit 11. The element electric field values of each of the antenna elements 2-1 to 2-M are stored in the element electric field value storage unit 12.

[0077] The determination unit 29 determines whether the evaluation beam power is within the range of the upper and lower thresholds. As described above, the evaluation beam power is calculated by the power calculation unit 26. The upper and lower thresholds are calculated by the threshold calculation unit 28. The determination unit 29 determines that the excitation error between antenna element systems is smaller than the excitation error target value when the evaluation beam power is within the range of the upper and lower threshold values. In other words, the determination unit 29 can determine whether the excitation error of the signal of each antenna element after calibration is smaller than the excitation error target value.

[0078] In this embodiment, the power calculation unit 26, the threshold calculation unit 28, and the determination unit 29 constitute the diagnostic device 100.

[0079] ***Explanation of operation*** Next, an example of the operation of the array antenna diagnostic system according to Embodiment 2 will be explained using Figure 4. Figure 4 is a flowchart showing an example of the operation of the array antenna diagnostic system according to Embodiment 2.

[0080] First, in step ST2-1, a diagnostic high-frequency signal is transmitted from antenna element 2-1, which is a reference antenna element within the array antenna 20. Specifically, the nominal value of the excitation coefficient for reference element evaluation, stored in the excitation coefficient storage unit 5, is set in the transmission DBF signal processing unit 22. Then, the transmitter 21-1 converts the diagnostic signal or a communication signal for separate communication input to the transmission DBF signal processing unit 22 from the input terminal 23 into a high-frequency signal. Then, antenna element 2-1, which is a reference antenna element, radiates the high-frequency signal into space. As a result, a high-frequency signal is transmitted toward the diagnostic antenna device 24.

[0081] In step ST2-2, the transmitted high-frequency signal is received by the diagnostic antenna 8. The receiver 25 then amplifies the received high-frequency signal and frequency-converts the amplified high-frequency signal to the intermediate frequency band. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal and acquires the converted digital signal as the received signal.

[0082] Here, the high-frequency signal transmitted from the transmitting DBF signal processing unit 22 to the transmitter 22-1 corresponding to antenna element 2-1 is represented as s. Also, the pass characteristics between each antenna element 2-m of the diagnostic antenna 8 and the array antenna 20, i.e., the element electric field value, is E. m This is how it is expressed. Also, the pass-through characteristic value of transmitter 21-m is A m This is how it is expressed. Note that the element's electric field value E m This is stored in the element electric field value storage unit 12. At this time, the high-frequency signal y1 transmitted by antenna element 2-1 and received by diagnostic antenna 8 can be expressed as y1 = A1E1s. In step ST2-2, the receiver 25 amplifies the high-frequency signal y1 and frequency-converts the amplified high-frequency signal xm to the intermediate frequency band. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal. The complex digital signal Y1 output by the receiver 25 can be expressed as Y1 = BA1E1s + N1, where N1 is the thermal noise component. Also, B is the pass-through characteristic of the receiver 25.

[0083] In step ST2-3, the power calculation unit 26 calculates the reference element power P1. As mentioned above, the reference element power P1 is the received power when the signal transmitted from the reference antenna element 2-1 is received by the diagnostic antenna 8. The power calculation unit 26 stores the calculated reference element power P1.

[0084] The power calculation unit 26 calculates the reference element power P1 using the complex digital signal Y1 = BA1E1s + N1 output by the receiver 25. The reference element power P1 is the square of the absolute value of the complex digital signal Y1. Specifically, the power calculation unit 26 calculates the reference element power P1 according to equation 10.

[0085]

number

[0086] In step ST2-4, the array antenna 20 transmits a high-frequency signal for diagnosis. Specifically, the calibrated excitation coefficient for the evaluation beam, stored in the excitation coefficient storage unit 5, is set in the transmitting DBF signal processing unit 22. Then, each of the transmitters 21-m converts the diagnostic signal or communication signal for separate communication input to the transmitting DBF signal processing unit 22 from the input terminal 23 into a high-frequency signal. Furthermore, each of the antennas 2-m radiates a high-frequency signal into space as an evaluation beam. As a result, a high-frequency signal is transmitted toward the diagnostic antenna device 24. The excitation coefficient storage unit 5 stores the nominal value W of the excitation coefficient for forming the evaluation beam. m The following is stored. Furthermore, the excitation coefficient storage unit 5 stores the calibration value C m Calibrated excitation coefficient W multiplied by ' m C m ' is stored. Calibration value C m ' is obtained by separate measurement. Each of the antenna elements 2-m transmits a high-frequency signal y, which is received by the diagnostic antenna 8. m is y m =W m C m 'A m E m It is expressed as s. The receiver 25 receives M high-frequency signals y, which is the number of antenna elements. m The combined value is entered.

[0087] In step ST2-5, the diagnostic high-frequency signal that has been transmitted is received by the diagnostic antenna 8. The receiver 25 then amplifies the received high-frequency signal and frequency-converts the amplified high-frequency signal to the intermediate frequency band. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal and acquires the converted digital signal as the received signal. The complex digital signal Y output by receiver 25 is given by Y = ΣBW m C m 'A m E m This is expressed as s + N, where N is the thermal noise component.

[0088] In step ST2-6, the power calculation unit 26 calculates the evaluation beam power P d . As described above, the evaluation beam power P d is the received power when the high-frequency signals transmitted from a plurality of antenna element systems m including the reference element system are received by the diagnostic antenna device 24. The power calculation unit 26 stores the calculated evaluation beam power P d .

[0089] The power calculation unit 26 calculates the evaluation beam power P m C m ’A m E m s+N using the complex digital signal Y = ΣBW d . The evaluation beam power P d is the square of the absolute value of the complex digital signal Y. Specifically, the power calculation unit 26 calculates the evaluation beam power P d according to Equation 11.

[0090]

Equation

[0091] Next, in step ST2-7, the threshold calculation unit 28 calculates the upper and lower threshold values of the evaluation beam power P m using the evaluation beam excitation coefficient nominal value W m , the reference element power P1, the element electric field value E d , and the excitation error target value. The evaluation beam excitation coefficient nominal value W m is stored in the second excitation coefficient storage unit 27 as described above. Also, the reference element power P1 is calculated in step ST2-3. The element electric field value E m is stored in the element electric field value storage unit 12. The excitation error target is stored in the excitation error target value storage unit 11.

[0092] Here, similar to the first embodiment, the calibration value C m ’ is the ideal calibration value C mThis is a value with an error relative to Δ. The amplitude error is Δ m And the phase error is δ m Therefore, the calibration value C m 'and the ideal calibration value C m is C m '=C m (1+Δ m )exp(jδ m ) has the following relationship. Also, when the thermal noise component is sufficiently small, equation 11 is the same form as equation 2, except that the pass-through characteristic value B of the receiver 25 is multiplied. Therefore, if the high-frequency signal component for diagnosis or communication among the signal components of the evaluation beam is sufficiently larger than the thermal noise component, the approximate value of the evaluation beam power is expressed as shown in Equation 3, similar to the case of Embodiment 1. As a result, in Embodiment 2 as well, the upper and lower threshold values ​​can be calculated in the same way as in Embodiment 1. That is, the threshold calculation unit 28 calculates, for example, the amplitude error Δ within the range of the assumed maximum amplitude error and phase error. m and phase error δ m The parameters are set randomly, and equation 3 is calculated many times as a trial. Then, the threshold calculation unit 28 evaluates the beam power P from the results of the trial calculations. d The maximum and minimum values ​​are obtained. Specifically, the threshold calculation unit 28 evaluates the beam power P using the maximum value. d Select the upper threshold value and evaluate the minimum value of beam power P. d Select this as the lower threshold. Furthermore, the threshold calculation unit 28 statistically evaluates equation 3 and evaluates the beam power P d The maximum and minimum values ​​may be obtained. Excitation coefficient nominal value W for forming the evaluation beam m However, as in the case of Embodiment 1, it is assumed that it is set to satisfy Equation 4. Excitation coefficient nominal value W m This corresponds to the excitation coefficient at which the high-frequency signals transmitted by each of the antenna elements 2-m are combined in phase at the diagnostic antenna 8 when there is no excitation error. In this case, similar to Embodiment 1, the threshold calculation unit 28 calculates the evaluation beam power P d The upper and lower threshold values ​​can be determined by equations 4 to 9.

[0093] Based on the above, in step ST2-7, the threshold calculation unit 28 calculates the nominal value W of the excitation coefficient for the evaluation beam that satisfies equation 8. m And, the reference element power P1 and the element electric field value E m Using the target excitation error value of the array antenna 20, the beam power P is evaluated according to equations 4 to 9. d Upper threshold P max and lower threshold P min The following is calculated. Note that the target value of the excitation error is the variance σ of the amplitude error. Δ 2 and the variance of the phase error σ δ 2 , or the sum of the two σ Δ 2 +σ δ 2 That is the case.

[0094] In step ST2-8, the determination unit 29 evaluates the beam power P d and upper threshold P max and lower threshold P min The two are compared and evaluated. That is, the determination unit 29 evaluates the beam power P d The upper threshold P max and lower threshold P min Determine if it is within the range. P min ≤P d ≤P max If this is the case, the determination unit 29 determines that the excitation error of each signal of the calibrated antenna element 2-m is smaller than the excitation error target value. On the other hand, P d <P min or P d >P max If so, the determination unit 29 determines that the excitation error of each signal of the calibrated antenna element 2-m is greater than the target excitation error value.

[0095] ***Explanation of the effects of the embodiment*** This embodiment also makes it possible to easily determine whether the excitation error after calibration is smaller than the target value.

[0096] Specifically, in the array antenna diagnostic system according to Embodiment 2, the reference element power of the DBF antenna is calculated based on a diagnostic signal transmitted from the reference element of the array antenna and received by the diagnostic antenna. Furthermore, a calibrated excitation coefficient for the evaluation beam, which is stored in advance, is set to form the evaluation beam. In addition, the evaluation beam power of the DBF antenna is calculated based on the diagnostic signal transmitted from the array antenna by the evaluation beam and received by the diagnostic antenna. Furthermore, the received power threshold of the evaluation beam is calculated using the reference element power, the pre-stored excitation coefficient for the evaluation beam, the element electric field value which is the pass-through characteristic between each antenna element and the diagnostic antenna, which is stored in advance, and the pre-stored excitation error target value. Then, it is evaluated whether the evaluation beam power is within the range defined by the received power threshold. As a result, the same effect as in Embodiment 1 can be obtained even when the array antenna to be diagnosed is a transmitting DBF antenna.

[0097] Embodiment 3. In this embodiment, similar to Embodiment 1, an example in which the array antenna is a receiving DBF antenna is described. In this embodiment, an example is described in which the excitation error after calibration is determined with higher precision using the element pattern of the antenna elements and the antenna directivity error. This embodiment will primarily describe the differences from Embodiment 1. Matters not described below are the same as in Embodiment 1.

[0098] ***Explanation of the structure*** Figure 5 shows an example of the configuration of the array antenna diagnostic system according to Embodiment 3. The array antenna diagnostic system according to Embodiment 3 consists of an array antenna 30 and a diagnostic antenna device 7.

[0099] In Figure 5, the diagnostic antenna device 7 is the same as the one described in Embodiment 1, so its description is omitted.

[0100] In the array antenna 30 to be diagnosed, an element pattern information storage unit 31 and an antenna directivity error storage unit 32 are added compared to the array antenna 1 described in Embodiment 1. Also, a threshold calculation unit 33 is provided instead of the threshold calculation unit 13. Other components of the array antenna 30 are denoted by the same reference numerals as in Figure 1. A detailed description of these components is omitted.

[0101] In Embodiment 1, the diagnostic antenna 8 could be installed at any position as long as the array antenna 1 could receive the radio waves radiated from the diagnostic antenna 8. However, in Embodiment 3, the diagnostic antenna 8 is installed opposite the array antenna 30 and at a position sufficiently far from the array antenna 30, which can be considered the so-called far field of the array antenna 30.

[0102] The element pattern information storage unit 31 stores element pattern information. Element pattern information refers to information about the shape of each element pattern of antenna elements 2-1 to 2-M. Examples of element pattern information include the peak direction, beamwidth, and various parameters that determine the phase distribution of each element pattern of antenna elements 2-1 to 2-M.

[0103] The antenna directivity error storage unit 32 stores an assumed value for the antenna directivity error of the array antenna 30. Antenna directivity error is the error from the nominal value of the direction of the diagnostic antenna 8 as seen from the array antenna 30. Antenna directivity error is an error in the direction of direction due to installation errors of the array antenna 30, and occurs due to errors in the installation positions of the array antenna 30 and the diagnostic antenna 8, etc. The antenna direction error storage unit 32 stores statistical values ​​of the magnitude of the antenna direction error expected during operation as an assumed value of the antenna direction error. Specifically, the antenna direction error storage unit 32 stores the standard deviation or variance of the magnitude of the antenna direction error expected during operation.

[0104] The threshold calculation unit 33 calculates the upper and lower threshold values ​​for the evaluation beam power (diagnostic power). More specifically, the threshold calculation unit 33 calculates the upper and lower threshold values ​​for the evaluation beam power using the nominal value of the excitation coefficient for the evaluation beam, the reference element power, the target excitation error value, the element electric field value of each of the antenna elements 2-1 to 2-M, as well as element pattern shape information and assumed values ​​of the antenna directivity error. The nominal value of the excitation coefficient for the evaluation beam is stored in the excitation coefficient storage unit 5. The reference element power is calculated by the power calculation unit 10. The excitation error target value is stored in the excitation error target value storage unit 11. The element electric field value of each antenna element 2-1 to 2-M is stored in the element electric field value storage unit 12. In addition, element pattern shape information is stored in the element pattern information storage unit 31. The assumed value of the antenna directivity error is stored in the antenna directivity error storage unit 32.

[0105] In this embodiment, the power calculation unit 10, the threshold calculation unit 33, and the determination unit 14 constitute the diagnostic device 100.

[0106] ***Explanation of operation*** Next, an example of the operation of the array antenna diagnostic system according to Embodiment 3 will be explained using Figure 6. Figure 6 is a flowchart showing an example of the operation of the array antenna diagnostic system according to Embodiment 3.

[0107] In Embodiment 1, we considered the ideal case where there is no antenna directivity error, that is, where there are no installation errors between the array antenna 1 and the diagnostic antenna 8. However, for example, if the array antenna is mounted on a satellite and the diagnostic antenna is installed on the ground, antenna directivity errors will occur due to the attitude errors of the satellite. As a result, the actual transmission characteristics between each of the antenna elements 2-1 to 2-M and the diagnostic antenna 8 will differ from the theoretical, calculated, or measured values ​​of the element electric field values ​​stored in the element electric field value storage unit 12. Therefore, in Embodiment 3, the threshold calculation unit 33 calculates the upper and lower threshold limits, taking into account the expected effect of antenna directivity errors.

[0108] Steps ST3-1, ST3-2, and ST3-3 perform the same operations as steps ST1-1, ST1-2, and ST1-3 in Embodiment 1, respectively. Therefore, their explanation is omitted.

[0109] In step ST3-4, the threshold calculation unit 33 calculates the nominal value W of the excitation coefficient for the evaluation beam. m The reference element power P1, the excitation error target value, and the element field values ​​E of each antenna element 2-1 to 2-M. m Then, using the element pattern shape information and the assumed value of the antenna directivity error, the upper and lower threshold values ​​of the evaluation beam power are calculated. Nominal value W for excitation coefficient for evaluation beam m This is stored in the excitation coefficient storage unit 5. Also, the reference element power P1 is calculated in step ST1-3. Element electric field value E m The element electric field value is stored in the element electric field value storage unit 12. The excitation error target is stored in the excitation error target value storage unit 11. Element pattern shape information is stored in the element pattern information storage unit 31. The assumed value of the antenna directivity error is stored in the antenna directivity error storage unit 32.

[0110] Here, the direction of the diagnostic antenna 8 as seen from the array antenna 30 when there is no antenna directivity error is (θ c , φ c Let ). Also, let (Δθ, Δφ) be the antenna directivity error between each of the antenna elements 2-1 to 2-M that transmit and receive high-frequency signals for diagnosis in steps ST3-1 and ST3-2 and the diagnostic antenna 8. At this time, the evaluated beam power P d The approximate value of takes the same form as Equation 7 and is expressed as shown in Equation 12 below.

[0111]

number

[0112] However, E m ' is (θ c+Δθ, φ c Equation 12 is the field field value of each element of antenna element 2-m in the +Δφ direction. Equation 12 is the amplitude error Δ m , phase error δ m It also changes depending on the magnitude of the antenna directivity error (Δθ, Δφ). Therefore, the evaluation beam power P generated by the expected maximum amplitude error, phase error, and antenna directivity error. d Evaluate the maximum and minimum values ​​of the variation in beam power P. d These can be used as the upper and lower threshold limits. Therefore, the threshold calculation unit 33 calculates the amplitude error Δ within the range of the expected maximum amplitude error, phase error, and antenna directivity error. m , phase error δ m The antenna directivity errors (Δθ, Δφ) are set randomly, and equation 12 is performed as a trial calculation many times. Then, the threshold calculation unit 33 evaluates the beam power P from the results of the trial calculation. d The maximum and minimum values ​​are obtained. The threshold calculation unit 33 evaluates the beam power P using the maximum value. d Select the upper threshold value and evaluate the minimum value of beam power P. d Select this as the lower threshold. Furthermore, the threshold calculation unit 33 statistically evaluates equation 12 and evaluates the beam power P d The maximum and minimum values ​​may also be obtained. In this case as well, the threshold calculation unit 33 evaluates the beam power P using the maximum value. d Select the upper threshold value and evaluate the minimum value of beam power P. d Select this as the lower threshold.

[0113] Generally, in the (θ, φ) coordinate system of an array antenna, the element pattern shows that near the beam center, the amplitude decreases monotonically as it moves away from the peak direction. On the other hand, the phase changes linearly with respect to (θ, φ). Therefore, the element pattern of each antenna element 2-m near the beam center is expressed by Equation 13.

[0114]

number

[0115] However, Em0 The peak amplitudes of each antenna element 2-m are shown. Also, (θ m , φ m ) indicates the beam peak direction of each antenna element 2-m. m The parameter that defines the beam width of each antenna element 2-m is shown. θm The coefficients in the θ direction of the phase distribution of each antenna element 2-m are shown. φm This shows the coefficients in the φ direction of the phase distribution of each antenna element 2-m. m The values ​​shown represent the phase values ​​in the beam peak direction for each antenna element 2-m. (θ, φ) = (θ c +Δθ, φ c The elemental electric field value E of each antenna element 2-m in the +Δφ direction m When (Δθ, Δφ) is sufficiently small, it can be approximated as shown in Equation 14.

[0116]

number

[0117] Typically, the beam width is approximately equal for all antenna elements in an array antenna. That is, b m It can be considered as ~b. Furthermore, when each error component is sufficiently small, their second-order components can be considered to be sufficiently smaller than their first-order components. For this reason, from equations 12 to 14, the approximate value of the evaluated beam power is given by the following equation 15.

[0118]

number

[0119] However, d θm =θ m -θ1, d φm =φ m-φ1. If the array antenna 30 is an array-fed reflector type antenna, the beam peak directions are usually different for each element. An array-fed reflector type antenna is an antenna that forms a beam by passing the radio waves radiated from each antenna element through a separately provided reflector. In this case, the antenna is designed so that the beams of each antenna element are evenly distributed across the service area, with each beam being roughly at equal intervals within the service area. That is, d θm ~d θ d φm ~d φ It can be considered as such. Also, the inclination of the phase pattern of the element pattern near the beam center of each antenna element 2-m is usually approximately equal for all antenna elements. For this reason, a θm ~a θ a φm ~a θ This can be considered as follows. In this case, the evaluation beam power can be approximated as shown in Equation 16.

[0120]

number

[0121] Equation 16 shows that the excitation coefficient is W. m E m (θ c , φ c ) can be seen as a constant multiple of the square of the amplitude F of the composite electric field of an array antenna having an omnidirectional antenna element pattern having the amplitude error given by Equation 17 and the phase error given by Equation 18.

[0122]

number

[0123]

number

[0124] Equation 16 is the amplitude error Δ from Equation 3. mand phase error δ m These are simply replaced with equations 17 and 18, respectively. Therefore, the same argument as in the case of embodiment 1 holds true in embodiment 3. That is, in this embodiment, the threshold calculation unit 33 calculates the evaluation beam power P d Upper threshold P max The value is determined as shown in Equation 19. Furthermore, the threshold calculation unit 33 determines the evaluation beam power P d Lower threshold P min Determine this as shown in Equation 20.

[0125]

number

[0126]

number

[0127]

number

[0128]

number

[0129]

number

[0130]

number

[0131]

number

[0132]

number

[0133] However, σ Δ 2 =E[Δ m 2 ], σ δ 2 =E[δ m 2 ], σ θ 2 =E[Δθ 2 ], σ φ 2 =E[Δφ 2 ] Based on the above, in step ST3-4, the threshold calculation unit 33 calculates the nominal value W of the excitation coefficient for the evaluation beam that satisfies equation 22. m The reference element power P1 and the element electric field value E in the direction of the diagnostic antenna 8 as seen from the array antenna 30 when there is no antenna directivity error. m (θ c , φ c Using the target excitation error value of the array antenna 30, element pattern shape information, and assumed value of the antenna directivity error, the evaluation beam power P d Upper threshold P max and lower threshold P min Calculate. The target value for excitation error is the variance σ of the amplitude error. Δ 2 and the variance of the phase error σ δ 2 , or the sum of the two σ Δ 2 +σ δ 2 That is the case. Furthermore, the element pattern shape information includes parameter b which defines the beam width, and d which indicates the spacing between each of the antenna elements 2-m in the beam peak direction. θ and d φ , a coefficient that indicates the slope of the phase distribution of each element pattern of antenna element 2-m. θ and a φ That is the case. Furthermore, the assumed value of the antenna directivity error is the variance σ of the assumed antenna directivity error in the θ direction. θ 2 and the variance σ of the antenna directivity error in the φ direction Φ 2 That is the case.

[0134] In the above explanation, we used the example of an array antenna 30 being an array-fed reflector type antenna. However, the above explanation is also applicable when the array antenna 30 is a so-called direct-radiation type antenna that forms a beam directly from the radio waves radiated from each antenna element. In a direct-radiating array antenna, the beam peak direction is usually approximately equal across all antenna elements, d θm =d φm = 0. That is, in a direct-radiating array antenna, d in equation 25 θ =d φ By setting = 0, the beam power P can be evaluated according to equations 19 to 26, similar to the case of an array-fed reflector antenna. d Upper threshold P max and lower threshold P min It is possible to calculate this.

[0135] In step ST3-5, the determination unit 14 evaluates the beam power P d and upper threshold P max and lower threshold P min The two are compared and evaluated. That is, the determination unit 14 evaluates the beam power P d The upper threshold P max and lower threshold P min Determine if it is within the range. P min ≤P d ≤P max If this is the case, the determination unit 14 determines that the excitation error of each signal of the calibrated antenna element 2-m is smaller than the excitation error target value. On the other hand, P d <P min or P d >P max If so, the determination unit 14 determines that the excitation error of each signal of the calibrated antenna element 2-m is greater than the target excitation error value.

[0136] ***Explanation of the effects of the embodiment*** According to this embodiment, by using the element pattern of the antenna element and the antenna directivity error, it is possible to determine with higher precision whether or not the excitation error after calibration is smaller than the target value.

[0137] More specifically, in the array antenna diagnostic system according to Embodiment 3, the reference element power and evaluation beam power of the DBF antenna are calculated based on a pre-stored reference element evaluation excitation coefficient and a calibrated evaluation beam excitation coefficient, using a diagnostic signal transmitted from a diagnostic antenna installed opposite the array antenna at a position where the radio waves received by the array antenna can be considered as the so-called far field, and the diagnostic signal transmitted from the diagnostic antenna. Furthermore, the received power threshold of the evaluation beam is calculated using a pre-stored uncalibrated evaluation beam excitation coefficient, a pre-stored element electric field value which is the pass-through characteristic between each antenna element and the diagnostic antenna, a pre-stored excitation error target value, a pre-stored information on the shape of the element pattern, and a pre-stored assumed value of the antenna directivity error. By evaluating whether the evaluation beam power is within the range defined by the received power threshold, the same effect as in Embodiment 1 can be obtained even when there is an antenna directivity error.

[0138] Embodiment 4. In this embodiment, similar to Embodiment 1, an example is described in which the array antenna is a receiving DBF antenna. In this embodiment, an example is described in which a diagnostic signal generated within the array antenna is received, rather than receiving a diagnostic signal from an external antenna. This embodiment will primarily describe the differences from Embodiment 1. Matters not described below are the same as in Embodiment 1.

[0139] ***Explanation of the structure*** Figure 7 shows an example configuration of the array antenna diagnostic system according to Embodiment 4. The array antenna diagnostic system according to Embodiment 4 consists only of an array antenna 40. The array antenna 40 is the DBF antenna to be diagnosed.

[0140] In the array antenna 40, compared to the array antenna 1 described in Embodiment 1, diagnostic signal input circuits 41-1 to 41-M are added between the antenna elements 2-1 to 2-M and the receivers 3-1 to 3-M. Furthermore, a diagnostic signal generation circuit 42, a distribution circuit 43, a diagnostic signal extraction unit 44, a diagnostic excitation coefficient storage unit 45, and a pass-through characteristic value storage unit 47 are added. Furthermore, a power calculation unit 46 is provided instead of the power calculation unit 10. Also, a threshold calculation unit 48 is provided instead of the threshold calculation unit 13. Also, a determination unit 49 is provided instead of the determination unit 14. Diagnostic signal input circuits 41-1 to 41-M are sometimes collectively referred to as diagnostic signal input circuit 41-m. In the array antenna 40, the same components as in Figure 1 are denoted by the same reference numerals. Descriptions of the components identical to those in Figure 1 are omitted.

[0141] In Embodiment 1, the configuration involved transmitting a diagnostic signal from an external diagnostic antenna 8 to the array antenna 1. In Embodiment 4, the array antenna 40 includes a mechanism for generating a diagnostic signal. The diagnostic signal is then input to each antenna element system via the distribution circuit 43 and the diagnostic signal input circuits 41-1 to 41-M.

[0142] The diagnostic signal input circuits 41-1 to 41-M input the diagnostic high-frequency signals generated by the diagnostic signal generation circuit 42 to each antenna element system. The diagnostic signal input circuits 41-1 to 41-M are composed of, for example, combining circuits and directional couplers. Each of the diagnostic signal input circuits 41-m is installed in the middle of the signal line between the antenna element 2-m and the receiver 3-m. Each of the diagnostic signal input circuits 41-m inputs a high-frequency diagnostic signal generated by the diagnostic signal generation circuit 42 to the signal line.

[0143] In this embodiment, the antenna element system m consists of the antenna element 2-m, the receiver 3-m, the diagnostic signal input circuit 41-m, and the connecting wires that link them together.

[0144] The diagnostic signal generation circuit 42 generates known high-frequency signals for diagnosing the array antenna 40. The diagnostic signal generation circuit 42 is a signal source that generates, for example, a continuous wave or various modulated waves. The diagnostic signal generation circuit 42 is composed of, for example, a circuit combining an oscillator, a synthesizer circuit, a modulation circuit, a frequency mixer, and an amplifier. The diagnostic high-frequency signal generated by the diagnostic signal generation circuit 42 is input to the distribution circuit 43. If the array antenna 40 is also providing a separate service such as communication, the diagnostic high-frequency signal used is one that can be separated from the communication signal of the array antenna 40 by some means. As the diagnostic high-frequency signal, for example, a signal in a frequency band different from the frequency band used by the array antenna 40 for communication, or a spread spectrum signal, may be used. The diagnostic signal generation circuit 42 corresponds to the signal generation unit.

[0145] The distribution circuit 43 distributes the high-frequency diagnostic signals output from the diagnostic signal generation circuit 42 to the diagnostic signal input circuits 41-1 to 41-M.

[0146] The diagnostic signal extraction unit 44 extracts the diagnostic signals that have passed through each of the antenna element systems m from each output signal of the receiver 3-m. If the diagnostic high-frequency signal is a high-frequency signal having a frequency band different from the frequency band used by the array antenna 40 for communication, the diagnostic signal extraction unit 44 extracts the diagnostic high-frequency signal in the following manner, for example. The diagnostic signal extraction unit 44 performs discrete Fourier transform, digital filtering, etc., on the signals output by receivers 3-1 to 3-M. The diagnostic signal extraction unit 44 then separates only the signals in the frequency band corresponding to the diagnostic high-frequency signal and extracts the diagnostic high-frequency signal. Furthermore, if the diagnostic high-frequency signal is a spread-spectrum signal, the diagnostic signal extraction unit 44 performs despreading processing on the signals output by the signal receivers 3-1 to 3-M using a predetermined spreading code to extract the diagnostic high-frequency signal.

[0147] The diagnostic excitation coefficient storage unit 45 stores an excitation coefficient to be multiplied by the output signal of the receiver 3-m for the purpose of diagnosing the array antenna 40. The diagnostic excitation coefficient storage unit 45 stores the excitation coefficient for evaluating the reference element and the nominal value of the evaluation excitation coefficient as excitation coefficients necessary for diagnosing the array antenna 40. The excitation coefficient for reference element evaluation is an excitation coefficient used to calculate the power of the reference element, and it assigns a weight of 1 to the reference element and 0 to other antenna elements. The nominal value of the excitation coefficient for evaluation is the nominal value of the excitation coefficient used to calculate the upper and lower threshold values ​​of the evaluation power. Furthermore, the diagnostic excitation coefficient storage unit 45 also stores the calibrated excitation coefficients for evaluation. The calibrated excitation coefficient for evaluation is obtained by multiplying the nominal value of the excitation coefficient for the evaluation beam by a calibration value that is stored separately to correct for errors in the transmission characteristics of each antenna element system m.

[0148] The power calculation unit 46 calculates the reference element power and the evaluation power. In this embodiment, the evaluation power corresponds to the diagnostic power. The power calculation unit 46 multiplies the signals of each antenna element system m output by the diagnostic signal extraction unit 44 by the reference element evaluation excitation coefficient stored in the diagnostic excitation coefficient storage unit 45, and then synthesizes the signals of each antenna element system m after multiplication. Furthermore, the power calculation unit 46 calculates the reference element power by squaring the absolute value of the signal obtained by synthesis, that is, the signal of the reference element system output by the diagnostic signal extraction unit 44. Furthermore, the power calculation unit 46 multiplies the signals of each antenna element system m output by the diagnostic signal extraction unit 44 by the calibrated evaluation excitation coefficient stored in the diagnostic excitation coefficient storage unit 45. In addition, the power calculation unit 46 synthesizes the signals of each antenna element system m after multiplying by the calibrated evaluation excitation coefficient. Finally, the power calculation unit 46 calculates the evaluation power by squaring the absolute value of the signal obtained by the synthesis.

[0149] In this embodiment, the antenna element 2-1, which is the reference element, does not receive the diagnostic signal from the diagnostic signal generation circuit 42. Therefore, the reference element power calculated by the power calculation unit 46 is not, strictly speaking, the received power when the reference element system, including the antenna element 2-1, actually receives the diagnostic signal. However, as will be described later, the pass-through characteristic value between the diagnostic signal generation circuit 42 and the input terminal of the receiver 3-1 is reflected in the calculation of the reference element power by the power calculation unit 46. As a result, the power calculation unit 46 can calculate the same received power as the reference element power when the reference element system, including the antenna element 2-1, actually receives the diagnostic signal.

[0150] Similarly, each of the antenna elements 2-m does not receive a diagnostic signal from the diagnostic signal generation circuit 42. Therefore, the evaluation power calculated by the power calculation unit 46 is not, strictly speaking, the received power when each of the antenna element systems m actually receives a diagnostic signal. However, as will be described later, the pass-through characteristic value between the input terminals of the diagnostic signal generation circuit 42 and each of the receivers 3-m is reflected in the calculation of the evaluation power by the power calculation unit 46. As a result, the power calculation unit 46 can calculate the same received power as the received power when each of the antenna element systems m actually receives a diagnostic signal as the evaluation power.

[0151] The pass-through characteristic value storage unit 47 stores the theoretical, calculated, or measured values ​​of the amplitude and phase values ​​of the pass-through characteristic between the diagnostic signal generation circuit 42 and the respective input terminals of the receiver 3-m.

[0152] The threshold calculation unit 48 calculates the upper and lower threshold values ​​for the evaluation power (diagnostic power). More specifically, the threshold calculation unit 48 calculates the upper and lower threshold values ​​of the evaluation power using the nominal value of the evaluation excitation coefficient, the reference element power, the target excitation error value, and the pass-through characteristic value between the input terminals of the diagnostic signal generation circuit 42 and the receiver 3-m. As mentioned above, the nominal value of the evaluation excitation coefficient is stored in the diagnostic excitation coefficient storage unit 45. The reference element power is calculated by the power calculation unit 46. The excitation error target value is stored in the excitation error target value storage unit 11. The pass-through characteristic value is stored in the pass-through characteristic value storage unit 47.

[0153] The determination unit 49 determines whether the evaluation power is within the range of the upper and lower thresholds. As described above, the evaluation power is calculated by the power calculation unit 46. The upper and lower thresholds are calculated by the threshold calculation unit 48. The determination unit 49 determines that the excitation error between antenna element systems is smaller than the excitation error target value when the evaluation power is within the range of the upper and lower threshold values. In other words, the determination unit 49 can determine whether the excitation error of the signal of each antenna element after calibration is smaller than the excitation error target value. The determination unit 49 outputs a determination result, that is, a determination result of whether or not the excitation error is smaller than the excitation error target value.

[0154] In this embodiment, the power calculation unit 46, the threshold calculation unit 48, and the determination unit 49 constitute the diagnostic device 100.

[0155] ***Explanation of operation*** Next, an example of the operation of the array antenna diagnostic system according to Embodiment 4 will be explained using Figure 8. Figure 8 is a flowchart showing an example of the operation of the array antenna diagnostic system according to Embodiment 4.

[0156] First, in step ST4-1, a diagnostic signal (a high-frequency diagnostic signal) is transmitted from the diagnostic signal generation circuit 42 to each of the antenna element systems m. Specifically, the diagnostic signal generation circuit 42 generates a diagnostic signal. Then, the diagnostic signal generation circuit 42 transmits the diagnostic signal to the receiver 3-m via the distribution circuit 43 and the diagnostic signal input circuit 41-m, respectively.

[0157] In step ST4-2, the transmitted high-frequency signal is received by each of the receivers 3-1 to 3-M. Each of the receivers 3-1 to 3-M then amplifies the received high-frequency signal and frequency-converts the amplified high-frequency signal to the intermediate frequency band. Furthermore, each of the receivers 3-1 to 3-M converts the frequency-converted analog signal into a digital signal and acquires the converted digital signal as the received signal.

[0158] Here, the high-frequency signal for diagnosis transmitted by the diagnostic signal generation circuit 42 is denoted as s1. Furthermore, the pass-through characteristic value between the diagnostic signal generation circuit 42 and the input terminal of each receiver 3-m is T. m This is how it is expressed. Note that the pass-through characteristic value T m This is stored in the pass-through characteristic value storage unit 47. Furthermore, if the array antenna 40 is also providing a separate service such as communication, the received signal will have a communication signal superimposed on it in addition to the diagnostic high-frequency signal transmitted in step ST4-1. Let s2 be the communication signal. m is z m =T m It can be expressed as s1 + s2. In step ST4-2, this high-frequency signal z m Receiver 3-m amplifies the signal and then frequency-converts the amplified high-frequency signal zm to an intermediate frequency band. Furthermore, receiver 3-m converts the frequency-converted analog signal into a digital signal. The complex digital signal Z output by each receiver 3-m m is, Z m =A m T m s1+A m s2+N m It can be expressed as follows: However, N m This is a thermal noise component. Also, A m This is the pass-through characteristic value of receiver 3-m.

[0159] In step ST4-3, the diagnostic signal extraction unit 44 extracts the component corresponding to the diagnostic signal that has passed through each antenna element system m from the digital signal output by each receiver 3-m. That is, the diagnostic signal extraction unit 44 extracts the complex digital signal Z mOf these, only the terms dependent on s1 are extracted. Here, the processing gain during extraction is K, and the output signal Z of the diagnostic signal extraction unit 44. m ', including residual noise components, Z m '=K(A m T m s1+N m ) is expressed as.

[0160] In step ST4-4, the power calculation unit 46 calculates the reference element power P1 and the evaluation beam power P d Calculate.

[0161] The power calculation unit 46 calculates the reference element power P1 using the output signal Z1'=K(A1T1s1+N1) from the diagnostic signal extraction unit 44 based on the signal from the receiver 3-1. The reference element power P1 is the square of the absolute value of the output signal Z1' of the diagnostic signal extraction unit 44. Specifically, the power calculation unit 46 calculates the reference element power P1 according to equation 27.

[0162]

number

[0163] Next, the evaluation power P d Let's consider this. The evaluation signal is the output result Z of the diagnostic signal extraction unit 44. m Multiply ' by an appropriate excitation coefficient, and the output signal Z after multiplication m The signal obtained by synthesizing ' is used. Pass-through characteristic value A of receiver 3-m m This varies from receiver to receiver. Therefore, typically, the pass-through characteristic value A m The DBF signal processing is performed after calibration to ensure that the influence on the communication signal is equal across all receivers 3-m. For evaluation signals, the same process is used as for communication signals, including the output signal Z. m Calibration is performed on ', and the output signal Z after calibration is generated. m Synthesize '. The diagnostic excitation coefficient storage unit 45 stores the nominal value W of the evaluation excitation coefficient. m In addition, a calibration value C obtained separately through measurement, etc. mCalibrated excitation coefficient W multiplied by ' m C m ' is remembered. Power P for evaluation d This is the output signal Z of the diagnostic signal extraction unit 44 based on the signals from each receiver 3-m. m Calibrated evaluation excitation coefficient W m C m It is obtained by multiplying by ', synthesizing the multiplied signal, and squaring the absolute value of the synthesized signal. Specifically, the power calculation unit 46 calculates the evaluation power P according to equation 28. d Calculate.

[0164]

number

[0165] Next, in step ST4-5, the threshold calculation unit 48 calculates the nominal value W of the excitation coefficient for evaluation. m The reference element power P1 and the pass-through characteristic value T m Using the excitation error target value, the evaluation power P d Calculate the upper and lower threshold values. Nominal value W for the excitation coefficient used for evaluation m As mentioned above, this is stored in the diagnostic excitation coefficient storage unit 45. The reference element power P1 is calculated in step ST4-4. Pass-through characteristic value T m The pass-through characteristic value is stored in the pass-through characteristic value storage unit 47. The excitation error target is stored in the excitation error target value storage unit 11.

[0166] Calibration value C m ' is the ideal calibration value C due to the influence of thermal noise. m This value has an error relative to Δ. Here, the amplitude error is Δ m And the phase error is δ m This shall be the case. Also, similar to Embodiment 1, the calibration value C m 'and the ideal calibration value C m is C m '=C m (1+Δ m )exp(jδ m Assume that they have the following relationship. Equations 27 and 28 are |K| 2 Except for the fact that a constant is multiplied, it is in the same form as equations 1 and 2 which represent the reference element power and evaluation beam power in Embodiment 1. Therefore, if the diagnostic signal component of the evaluation signal is sufficiently larger than the thermal noise component, the evaluation power P is used, as in Embodiment 1. d The approximate value of can be expressed by a similar equation to Equation 3, which is given by Equation 29.

[0167]

number

[0168] As can be seen from Equation 29, the evaluation power P d The amplitude error is Δ m , phase error δ m It changes depending on the magnitude. Therefore, the evaluation power P generated by the expected maximum amplitude error and phase error is d The maximum and minimum values ​​of the fluctuations are used to evaluate power P. d These can be used as the upper and lower threshold limits. Therefore, the threshold calculation unit 48 calculates the amplitude error Δ within the range of the expected maximum amplitude error and phase error, for example. m and phase error δ m The parameters are set randomly, and equation 29 is performed as a trial calculation many times. Then, the threshold calculation unit 48 calculates the evaluation power P from the results of the trial calculation. d The maximum and minimum values ​​are obtained. The threshold calculation unit 48 uses the maximum value as the evaluation power P. d Select the upper threshold value and use the minimum value as the evaluation power P. d Select this as the lower threshold. Furthermore, the threshold calculation unit 48 statistically evaluates equation 29 using the same method as in Embodiment 1, and evaluates the power P d The maximum and minimum values ​​of the evaluation power P may be obtained. That is, the threshold calculation unit 48 calculates the evaluation power P d The upper and lower thresholds are defined in E in equations 4 to 9. m to T m It can be determined by the formula in which the following is substituted:

[0169] Therefore, in step ST4-5, the threshold calculation unit 48 calculates Equation 4 (where E m to T m Nominal value W of the excitation coefficient for evaluation that satisfies (replace with) m The reference element power P1 and the pass-through characteristic value T. m Using the excitation error target value, equations 4 to 9 (where E m to T m (replace with) the evaluation power P d Upper threshold P max and lower threshold P min The following is calculated. Note that the target value of the excitation error is the variance σ of the amplitude error. Δ 2 and the variance of the phase error σ δ 2 , or the sum of the two σ Δ 2 +σ δ 2 That is the case.

[0170] In step ST4-6, the determination unit 49 determines the evaluation power P d and upper threshold P max and lower threshold P min The two are compared and evaluated. That is, the determination unit 49 determines the evaluation power P d The upper threshold P max and lower threshold P min Determine if it is within the range. P min ≤P d ≤P max If this is the case, the determination unit 49 determines that the excitation error of each signal of the calibrated antenna element 2-m is smaller than the excitation error target value. On the other hand, P d <P min or P d >P max If so, the determination unit 49 determines that the excitation error of each signal of the calibrated antenna element 2-m is greater than the target excitation error value.

[0171] ***Explanation of the effects of the embodiment*** According to this embodiment, it is possible to easily determine whether the excitation error after calibration is smaller than the target value, even without receiving a diagnostic signal from an external antenna.

[0172] Specifically, in the array antenna diagnostic system according to Embodiment 4, a diagnostic signal transmitted from the diagnostic signal generation circuit is input to the DBF antenna via the diagnostic signal input circuit. The diagnostic signal extraction unit then extracts the diagnostic signal from the received signal. Using the extracted signal, the reference element power and evaluation power of the DBF antenna are calculated based on a pre-stored reference element evaluation excitation coefficient and a calibrated evaluation excitation coefficient. The received power threshold is calculated using the reference element power, a pre-stored pre-calibrated evaluation excitation coefficient, a pre-stored pass-through characteristic value between the diagnostic signal generation circuit and each receiver, and a pre-stored predetermined excitation error target value. The evaluation power is then evaluated to determine whether it falls within the range defined by the received power threshold. As a result, the same effects as in Embodiment 1 can be obtained even when the array antenna itself is equipped with a diagnostic signal generation circuit.

[0173] Embodiment 5. In this embodiment, similar to Embodiment 2, an example is described in which the array antenna is a transmitting DBF antenna. In this embodiment, an example is described in which the diagnostic signal is transmitted to a receiver within the array antenna, rather than to an external antenna. This embodiment will primarily explain the differences from Embodiments 1, 2, and 4. Matters not described below are the same as in Embodiments 1, 2, and 4.

[0174] ***Explanation of the structure*** Figure 9 shows an example of the configuration of an array antenna diagnostic system according to Embodiment 5. The array antenna diagnostic system according to Embodiment 5 consists only of an array antenna 50. The array antenna 50 is the DBF antenna to be diagnosed.

[0175] The array antenna 50 is a transmitting DBF antenna, and compared to the array antenna 20 described in Embodiment 2, a diagnostic signal input section 51 is added between the transmitters 21-1 to 21-M and the transmitting DBF signal processing unit 22. In addition, a second distribution circuit 52-1 to 52-M is added between the antenna elements 2-1 to 2-M and the transmitters 21-1 to 21-M. The second distribution circuit 52-1 to 52-M may be collectively referred to as the second distribution circuit 52-m. Furthermore, a diagnostic excitation coefficient storage unit 53, a combining circuit 54, a receiver 25, a diagnostic signal extraction unit 55, and a pass-through characteristic value storage unit 57 have been added. Furthermore, a power calculation unit 56, a threshold calculation unit 58, and a determination unit 59 are provided. Other components of the array antenna 50 are denoted by the same reference numerals as in Figure 3. A detailed description of these components is omitted.

[0176] In Embodiment 2, the array antenna 20 was diagnosed based on the received signal received by an external diagnostic antenna device 24. In Embodiment 5, the array antenna 50 itself is equipped with a function to receive a diagnostic signal. Then, the array antenna 50 is diagnosed based on the received signal.

[0177] The diagnostic signal input unit 51 generates a known digital signal for diagnosing the array antenna 50. The diagnostic signal input unit 51 also multiplies the generated digital signal by a diagnostic excitation coefficient stored in the diagnostic excitation coefficient storage unit 53. The diagnostic signal input unit 51 then inputs the signal after the excitation coefficient has been multiplied to the antenna element system m. In addition, the diagnostic signal input unit 51 may add the signal after the excitation coefficient has been multiplied to the digital signal output by the transmitting DBF signal processing unit 22 for the antenna element system m. In this case, the signal after the digital signal output by the transmitting DBF signal processing unit 22 has been added is input to the antenna element system m. If the array antenna 50 does not provide communication or other services, the diagnostic signal may be a signal with any frequency band. On the other hand, if the array antenna 50 does provide communication or other services, the diagnostic signal may be a signal with a frequency band different from the frequency band used by the array antenna 50 for communication. Furthermore, even when the array antenna 50 is providing other services such as communication, the diagnostic signal may be a spread spectrum signal in order to enable separation and extraction from the communication signal.

[0178] The second distribution circuits 52-1 to 52-M each distribute the high-frequency signals output by the transmitters 21-1 to 21-M. Then, each of the second distribution circuits 52-1 to 52-M outputs a portion of the signals obtained by the distribution to the combining circuit 54. Each of the second distribution circuits 52-1 to 52-M is composed of, for example, a distribution circuit or a directional coupler. The second distribution circuit 52-m is installed in the middle of the signal line between the antenna element 2-m and the transmitter 2-m. The second distribution circuit 52-m distributes the high-frequency signal output from the transmitter 21-m, outputting some of the signal to the antenna element 2-m and the other signal to the combining circuit 54.

[0179] In this embodiment, the antenna element system m consists of the antenna element 2-m, the second distribution circuit 52-m, the transmitter 21-m, and the connecting wires that link them together.

[0180] The diagnostic excitation coefficient storage unit 53 stores the diagnostic excitation coefficients. The diagnostic excitation coefficients are used to generate evaluation signals for diagnosing the array antenna 50. A diagnostic excitation coefficient is provided for each antenna element system m. The diagnostic excitation coefficients are set in the diagnostic digital signal generated by the diagnostic signal input unit 51. The diagnostic excitation coefficient storage unit 53 stores the excitation coefficient for evaluating the reference element and the nominal value of the excitation coefficient for the evaluation beam as diagnostic excitation coefficients. The excitation coefficient for reference element evaluation is the nominal value of the excitation coefficient used to calculate the power of the reference element. It is an excitation coefficient that assigns a weight of 1 to the reference element and 0 to other antenna elements. The nominal value of the excitation coefficient for evaluation is the nominal value of the excitation coefficient used to calculate the upper and lower threshold values ​​of the evaluation power. Furthermore, the diagnostic excitation coefficient storage unit 53 also stores the calibrated excitation coefficients for evaluation. The calibrated excitation coefficient for evaluation is obtained by multiplying the nominal value of the evaluation excitation coefficient by a calibration value that is stored separately to correct for errors in the transmission characteristics of each antenna element system m.

[0181] The combining circuit 54 combines the high-frequency signals output from the second distribution circuits 52-1 to 52-M. The combining circuit 54 then outputs the combined signal to the receiver 25.

[0182] The diagnostic signal extraction unit 55 extracts evaluation signals from the output digital signals output by the receiver 25, after they have passed through each antenna element system m. For example, if the array antenna 50 does not provide communication or other services, and the diagnostic signal is a signal with an arbitrary frequency band, the diagnostic signal extraction unit 55 outputs the output digital signal of the receiver 25 as is as the evaluation signal. On the other hand, if the array antenna 50 provides services such as communication, and the diagnostic signal is a signal with a frequency band different from the frequency band used by the array antenna 50 for communication, the diagnostic signal extraction unit 55 will perform the following operations, for example. The diagnostic signal extraction unit 55 performs discrete Fourier transform, digital filtering, etc., on the output digital signal of the receiver 25. The diagnostic signal extraction unit 55 then separates only the signal in the frequency band corresponding to the diagnostic signal and extracts the evaluation signal. The diagnostic signal extraction unit 55 then outputs the extracted evaluation signal. Furthermore, if the diagnostic signal is a spread-spectrum signal, the diagnostic signal extraction unit 55 performs despreading processing using a predetermined spreading code. The diagnostic signal extraction unit 55 then extracts an evaluation signal and outputs the extracted evaluation signal.

[0183] The power calculation unit 56 calculates the reference element power and the evaluation power. In this embodiment, the evaluation power corresponds to the diagnostic power. More specifically, the power calculation unit 56 calculates the reference element power by squaring the absolute value of the signal based on the signal from the reference element system, which is generated and input in the diagnostic signal input unit 51 using the reference element evaluation excitation coefficient stored in the diagnostic excitation coefficient storage unit 53 and output from the diagnostic signal extraction unit 55. Furthermore, the power calculation unit 56 calculates the evaluation power by squaring the absolute value of the signal obtained by combining m signals from each antenna element system m, which are generated and input in the diagnostic signal input unit 51 using the calibrated evaluation excitation coefficient stored in the diagnostic excitation coefficient storage unit 53 and output from the diagnostic signal extraction unit 55.

[0184] In this embodiment, the reference element, antenna element 2-1, does not transmit a diagnostic signal. Therefore, the reference element power calculated by the power calculation unit 56 is not, strictly speaking, the received power when a diagnostic signal actually transmitted from the reference element system including antenna element 2-1 is received. However, as will be described later, the pass-through characteristic value between the input terminal of the second distribution circuit 52-1 and the receiver 25 is reflected in the calculation of the reference element power by the power calculation unit 56. As a result, the power calculation unit 56 can calculate the same received power as the reference element power when a diagnostic signal actually transmitted from the reference element system including antenna element 2-1 is received.

[0185] Similarly, each of the antenna elements 2-m does not transmit a diagnostic signal. Therefore, the evaluation power calculated by the power calculation unit 56 is not, strictly speaking, the received power when the diagnostic signals actually transmitted from each of the antenna element systems m are received. However, as will be described later, the pass-through characteristic value between each input terminal of the second distribution circuit 52-m and the receiver 25 is reflected in the calculation of the evaluation power by the power calculation unit 56. As a result, the power calculation unit 56 can calculate the received power when the diagnostic signals actually transmitted from each of the antenna element systems m are received as the evaluation power.

[0186] The pass-through characteristic value storage unit 57 stores the theoretical, calculated, or measured values ​​of the amplitude and phase values ​​of the pass-through characteristic between each input terminal of the second distribution circuit 52-m and the receiver 25.

[0187] The threshold calculation unit 58 calculates the upper and lower threshold values ​​for the evaluation power (diagnostic power). More specifically, the threshold calculation unit 58 calculates the upper and lower threshold values ​​of the evaluation power using the nominal value of the evaluation excitation coefficient, the reference element power, the target excitation error value, and the pass-through characteristic value between each input terminal of the second distribution circuit 52-m and the receiver 25. As mentioned above, the nominal value of the evaluation excitation coefficient is stored in the diagnostic excitation coefficient storage unit 53. The reference element power is calculated by the power calculation unit 56. The excitation error target value is stored in the excitation error target value storage unit 11. The pass-through characteristic value is stored in the pass-through characteristic value storage unit 57.

[0188] The determination unit 59 determines whether the evaluation power is within the range of the upper and lower thresholds. As described above, the evaluation power is calculated by the power calculation unit 56. The upper and lower thresholds are calculated by the threshold calculation unit 58. The determination unit 59 determines that the excitation error between antenna element systems is smaller than the excitation error target value when the evaluation power is within the range of the upper and lower threshold values. In other words, the determination unit 59 can determine whether the excitation error of the signal of each antenna element after calibration is smaller than the excitation error target value. The determination unit 59 outputs a determination result, that is, a determination result of whether or not the excitation error is smaller than the excitation error target value.

[0189] In this embodiment, the power calculation unit 56, the threshold calculation unit 58, and the determination unit 59 constitute the diagnostic device 100.

[0190] ***Explanation of operation*** Next, the operation of the array antenna diagnostic system according to Embodiment 5 will be explained using Figure 10. Figure 10 is a flowchart showing the operation of the array antenna diagnostic system according to Embodiment 5.

[0191] First, in step ST5-1, the diagnostic signal input unit 51 generates a diagnostic digital signal. Then, the diagnostic signal input unit 51 multiplies the diagnostic digital signal by the excitation coefficient for reference element evaluation. The excitation coefficient for reference element evaluation is stored in the diagnostic excitation coefficient storage unit 53. Furthermore, the diagnostic signal input unit 51 adds the multiplied signal to the signal of the reference element system and inputs the added signal to the reference element system. In this embodiment as well, the reference element system is an antenna element system that includes antenna element 2-1.

[0192] The diagnostic signal input to the reference element system in step ST5-1 is converted into a high-frequency signal by the transmitter 21-1, similar to the signals transmitted by each antenna element system. The transmitter 21-1 outputs the diagnostic signal, which has been converted into a high-frequency signal, to the second distribution circuit 52-1. The second distribution circuit 52-1 outputs a diagnostic signal to the combining circuit 54. The combining circuit 54 acquires a diagnostic signal. The combining circuit 54 combines the acquired diagnostic signal with a signal transmitted by another antenna element system. The combining circuit 54 outputs the combined signal to the receiver 25.

[0193] In step ST5-2, the receiver 25 receives the signal output from the combining circuit 54 and performs frequency conversion on the received signal. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal. The receiver 25 acquires the converted digital signal as the received signal.

[0194] Here, the diagnostic signal input by the diagnostic signal input unit 51 is denoted as s. Also, the pass-through characteristic value of the transmitter 21-m is A. m This is expressed as follows: The pass-through characteristic value between the input terminal of the second distribution circuit 52-m and the receiver 25 is T m This is how it is expressed. Note that the pass-through characteristic value T m This is stored in the pass-through characteristic value storage unit 57. Also, if the array antenna 50 is separately providing a communication or other service, the high-frequency signal for the communication transmitted through each antenna element system is stored in S m This is how it is expressed. Furthermore, the high-frequency signal v1 received by receiver 25 is given by v1 = T1A1s + ΣT m S m This is how it is expressed.

[0195] In step ST5-2, the receiver 25 amplifies the high-frequency signal v1. The receiver 25 then frequency-converts the amplified high-frequency signal v1 into an intermediate frequency band signal. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal. The complex digital signal V1 output by receiver 25 is given by V1 = BT1A1s + BΣT m S m This can be expressed as +N1, where B is the pass-through characteristic value of receiver 25, and N1 is the thermal noise component.

[0196] In step ST5-3, the diagnostic signal extraction unit 55 extracts the component corresponding to the diagnostic signal from the digital signal output by the receiver 25 in step ST5-3. That is, the diagnostic signal extraction unit 55 extracts only the term that depends on the diagnostic signal s from the complex digital signal V1. Here, the processing gain during extraction is denoted as K, and the output V1' of the diagnostic signal extraction unit 55, including residual thermal noise components, is expressed as V1' = K(BT1A1s + N1).

[0197] In step ST5-4, the power calculation unit 56 calculates the reference element power P1.

[0198] The power calculation unit 56 calculates the reference element power P1 using the output signal V1'=K(BT1A1s+N1)) from the diagnostic signal extraction unit 55. The reference element power P1 is the square of the absolute value of the output signal V1' of the diagnostic signal extraction unit 55. Specifically, the power calculation unit 56 calculates the reference element power P1 according to equation 30.

[0199]

number

[0200] In step ST5-5, the diagnostic signal input unit 51 generates a diagnostic digital signal. The diagnostic signal input unit 51 then multiplies the diagnostic digital signal by a calibrated evaluation excitation coefficient. The calibrated evaluation excitation coefficient is stored in the diagnostic excitation coefficient storage unit 53. Furthermore, the diagnostic signal input unit 51 adds the multiplied signal to the signal of each antenna element system and inputs the added signal to each antenna element system.

[0201] In step ST5-5, the diagnostic signals input to each antenna element system are converted into high-frequency signals in each of the transmitters 21-m. Each of the transmitters 21-m outputs a diagnostic signal, which has been converted into a high-frequency signal, to a second distribution circuit 52-m. Each of the second distribution circuits 52-m outputs a diagnostic signal to the combining circuit 54. The combining circuit 54 acquires diagnostic signals from each of the second distribution circuits 52-m and combines the acquired diagnostic signals. The combining circuit 54 outputs the combined signal to the receiver 25.

[0202] In steps ST5-6, the receiver 25 receives the signal output from the combining circuit 54 and performs frequency conversion on the received signal. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal. The receiver 25 acquires the converted digital signal as the received signal.

[0203] As described above, the diagnostic signal input by the diagnostic signal input unit 51 is represented as s. Also, the nominal value of the evaluation excitation coefficient stored in the diagnostic excitation coefficient storage unit 53 is W. m This expresses the calibration value obtained by a separate measurement as C m This is expressed as '. If the array antenna 50 is separately providing a communication or other service, the high-frequency signal for the communication transmitted through each antenna element system is S m This is how it is expressed. Furthermore, the high-frequency signal v received by receiver 25 is given by v = ΣT m A m W m C m 's+ΣT m S m This is how it is expressed. Furthermore, the corresponding complex digital signal V is expressed as V = Bv + N, where N is the thermal noise component.

[0204] In step ST5-7, the diagnostic signal extraction unit 55 extracts the component corresponding to the diagnostic signal from the digital signal output by the receiver 25 in step ST5-6. That is, the diagnostic signal extraction unit 55 extracts only the term that depends on the diagnostic signal s from the complex digital signal V. Here, the output signal V' of the diagnostic signal extraction unit 55 is given by V' = KBΣT, including residual thermal noise components. m A m W m C m It is represented as 's+KN.

[0205] In step ST5-8, the power calculation unit 56 calculates the evaluation power P d Calculate.

[0206] The power calculation unit 56 uses the output signal V' of the diagnostic signal extraction unit 55 to calculate the evaluation power P d Calculate the evaluation power P.d This is the square of the absolute value of the output signal V' of the diagnostic signal extraction unit 55. Specifically, the power calculation unit 56 calculates the evaluation power P according to equation 31. d Calculate.

[0207]

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[0208] Next, in step ST5-9, the threshold calculation unit 58 calculates the nominal value W of the excitation coefficient for evaluation. m The reference element power P1 and the pass-through characteristic value T m Using the excitation error target value, the evaluation power P d Calculate the upper and lower threshold values. Nominal value W for the excitation coefficient used for evaluation m As mentioned above, this is stored in the diagnostic excitation coefficient storage unit 53. The reference element power P1 is calculated in step ST5-4. Pass-through characteristic value T m The pass-through characteristic value is stored in the pass-through characteristic value storage unit 57. The excitation error target is stored in the excitation error target value storage unit 11.

[0209] When the thermal noise component is sufficiently small, Equation 31 is identical in form to Equation 28, which represents the evaluation power in Embodiment 4, except that it is multiplied by the pass-through characteristic value B of the receiver 25. Therefore, if the diagnostic signal component among the evaluation signal components is sufficiently larger than the thermal noise component, the approximate value of the evaluation power is expressed as shown in Equation 29, similar to the case of Embodiment 4. Accordingly, the threshold calculation unit 58 can calculate the upper and lower threshold values ​​in the same manner as in the case of Embodiment 4. That is, the threshold calculation unit 58 calculates the amplitude error Δ within the range of the assumed maximum amplitude error and phase error, for example. m and phase error δ m The parameters are set randomly, and equation 29 is performed as a trial calculation many times. Then, the threshold calculation unit 58 calculates the evaluation power P from the results of the trial calculation. d The maximum and minimum values ​​are obtained. The threshold calculation unit 58 uses the maximum value as the evaluation power P. d Select the upper threshold value and use the minimum value as the evaluation power P.d Select this as the lower threshold. Furthermore, the threshold calculation unit 58 statistically evaluates equation 29 and determines the evaluation power P d The maximum and minimum values ​​of may be obtained. Similar to the case of Embodiment 4, the threshold calculation unit 58 calculates Equations 4 to 9 (however, E m to T m (replaced by) the evaluation power P d The upper and lower threshold values ​​may be calculated.

[0210] Therefore, in step ST5-9, the threshold calculation unit 58 calculates Equation 4 (where E m to T m The nominal value W of the evaluation excitation coefficient that satisfies (replace with) m The reference element power P1 and the pass-through characteristic value T. m Using the target excitation error value of the array antenna 50, equations 4 to 9 (where E m to T m (Replace with) Evaluate beam power P d Upper threshold P max and lower threshold P min The following is calculated. Note that the target value of the excitation error is the variance σ of the amplitude error. Δ 2 and the variance of the phase error σ δ 2 , or the sum of the two σ Δ 2 +σ δ 2 That is the case.

[0211] In step ST5-10, the determination unit 59 determines the evaluation power P d and upper threshold P max and lower threshold P min The two are compared and evaluated. That is, the determination unit 59 determines the evaluation power P d The upper threshold P max and lower threshold P min Determine if it is within the range. P min ≤P d ≤P maxIf this is the case, the determination unit 59 determines that the excitation error of each signal of the calibrated antenna element 2-m is smaller than the excitation error target value. On the other hand, P d <P min or P d >P max If so, the determination unit 59 determines that the excitation error of each signal of the calibrated antenna element 2-m is greater than the target excitation error value.

[0212] ***Explanation of the effects of the embodiment*** According to this embodiment, it is possible to easily determine whether the excitation error after calibration is smaller than the target value without transmitting a diagnostic signal to an external antenna.

[0213] Specifically, in the array antenna diagnostic system according to Embodiment 5, a diagnostic signal generated in the diagnostic signal input unit based on pre-stored reference element evaluation excitation coefficients is input to the DBF antenna. The diagnostic signal is then extracted via a second distribution circuit and a diagnostic signal extraction unit. The reference element power of the DBF antenna is calculated using the extracted signal. Similarly, a diagnostic signal generated in the diagnostic signal input unit based on pre-stored calibrated evaluation excitation coefficients is input to the DBF antenna. The diagnostic signal is extracted, and the evaluation power of the DBF antenna is calculated using the extracted diagnostic signal. The received power threshold is calculated using the reference element power, pre-stored evaluation excitation coefficients, pre-stored pass-through characteristic values ​​between each second distribution circuit and the receiver, and pre-stored excitation error target values. Then, it is evaluated whether the evaluation power of the DBF antenna is within the range defined by the received power threshold. As a result, even when the array antenna to be diagnosed is a transmitting DBF antenna and the array antenna itself is equipped with a diagnostic signal input unit and a diagnostic signal extraction unit, the same effects as in Embodiment 1 can be obtained.

[0214] Embodiment 6. In this embodiment, similar to Embodiment 1, an example is described in which the array antenna is a receiving DBF antenna. In this embodiment, the calculation of the reference element power and the evaluation beam power is performed by the array antenna, and the calculation of the upper and lower thresholds of the evaluation beam power and the comparison of the evaluation beam power with the upper and lower thresholds are performed by elements other than the array antenna. This embodiment will primarily describe the differences from Embodiment 1. Matters not described below are the same as in Embodiment 1.

[0215] Figure 11 shows an example of the configuration of an array antenna diagnostic system according to Embodiment 6. The array antenna diagnostic system according to Embodiment 6 consists of an array antenna 60, a diagnostic antenna device 7, and an external device 61. The array antenna 60 is the DBF antenna to be diagnosed. In this embodiment, the array antenna 60 is mounted on a platform with limited computing power, such as an artificial satellite. A portion of the diagnostic calculations is performed within the array antenna 60, while the remaining calculations are performed by an external device 61 outside the array antenna 60. Note that in Figure 11, the same reference numerals are used for components identical to those in Figure 1. The explanation of components identical to those in Figure 1 is omitted.

[0216] Compared to the array antenna 1 described in Embodiment 1, the array antenna 60 has an additional received power information transmission circuit 62 and a received power information transmission antenna 63. On the other hand, the array antenna 60 does not have an excitation error target value storage unit 11, an element electric field value storage unit 12, a threshold calculation unit 13, and a determination unit 14. In the array antenna 60, the same components as in Figure 1 are denoted by the same reference numerals. Descriptions of the components identical to those in Figure 1 are omitted.

[0217] The external device 61 performs diagnostic processing on the array antenna based on the received power information sent from the array antenna 60. The external device 61 includes a received power information receiving antenna 64, a receiver 25, a received power information acquisition unit 65, an excitation error target value storage unit 11, an element electric field value storage unit 12, a second excitation coefficient storage unit 27, a threshold calculation unit 66, and a determination unit 67.

[0218] In the following explanation, we will use the example where the array antenna 60 is an array antenna mounted on an artificial satellite, and the diagnostic antenna device 7 and external device 61 are installed on the ground.

[0219] In the array antenna 60, the received power information transmission circuit 62 transmits received power information. The received power information transmission notifies the reference element power and evaluation beam power calculated by the power calculation unit 10. The received power information transmission circuit 62 encodes received power information that indicates the reference element power and the evaluation beam power. The received power information transmission circuit 62 also modulates the encoded signal and converts the modulated signal obtained by the modulation into a high-frequency signal. The received power information transmission circuit 62 transmits the high-frequency signal obtained by the frequency conversion as the received power information transmission signal. The received power information transmission circuit 62 is composed of, for example, an encoding circuit, a modulation circuit, an oscillator, a synthesizer circuit, a frequency mixer, an amplifier, and the like. The received power information transmission circuit 62 corresponds to the circuit that generates the telemetry signal of the artificial satellite.

[0220] The antenna 63 for transmitting received power information radiates the received power information transmission signal into space. The antenna 63 for transmitting received power information corresponds to the antenna that transmits telemetry signals from an artificial satellite.

[0221] In the external device 61, the received power information receiving antenna 64 receives the received power information transmission signal. The received power information receiving antenna 64 corresponds to an antenna that receives telemetry signals from an artificial satellite, and is an antenna for the ground station of the artificial satellite. The antenna 64 for receiving received power information outputs a received power information transmission signal to the receiver 25. The receiver 25 amplifies the received power information transmission signal and then frequency-converts the amplified received power information transmission signal to the intermediate frequency band. Furthermore, the receiver 25 converts the frequency-converted analog signal into a digital signal. The receiver 25 outputs the digital signal to the received power information acquisition unit 65.

[0222] The received power information acquisition unit 65 acquires received power information from the digital signal output by the receiver 25. As mentioned above, the received power information includes the reference element power and the evaluation beam power.

[0223] The threshold calculation unit 66 calculates the upper and lower threshold values ​​for the evaluation beam power. More specifically, the threshold calculation unit 66 calculates the upper and lower threshold values ​​of the evaluation beam power using the nominal value of the excitation coefficient for the evaluation beam, the reference element power, the target excitation error value, and the element electric field values ​​of each of the antenna elements 2-1 to 2-M. The nominal value of the excitation coefficient for the evaluation beam is stored in the second excitation coefficient storage unit 27. The reference element power is shown in the received power information. The excitation error target value is stored in the excitation error target value storage unit 11. The element electric field value of each antenna element 2-1 to 2-M is stored in the element electric field value storage unit 12.

[0224] The determination unit 67 determines whether the evaluation beam power is within the range of the upper and lower thresholds. The evaluation beam power is shown in the received power information. The upper and lower thresholds are calculated by the threshold calculation unit 66. The determination unit 67 determines that the excitation error between antenna element systems is smaller than the excitation error target value when the evaluation beam power is within the range of the upper and lower threshold values. In other words, the determination unit 67 can determine whether the excitation error of the signal of each antenna element after calibration is smaller than the excitation error target value.

[0225] In this embodiment, the power calculation unit 10 of the array antenna 60 and the threshold calculation unit 66 and determination unit 67 of the external device 61 constitute the diagnostic device 100.

[0226] ***Explanation of operation*** Next, an example of the operation of the array antenna diagnostic system according to Embodiment 6 will be described using Figure 12. Figure 12 is a flowchart showing an example of the operation of the array antenna diagnostic system according to Embodiment 6.

[0227] First, steps ST6-1, ST6-2, and ST6-3 perform the same operations as steps ST1-1, ST1-2, and ST1-3 in Embodiment 1, respectively. Therefore, their descriptions will be omitted.

[0228] In step 6-4, the received power information transmission circuit 62 generates a received power information transmission signal for transmitting the received power information. The received power information includes the reference element power P1 and the evaluation beam power P calculated by the power calculation unit 10 in step ST6-3. d This is shown. Then, the received power information transmission antenna 63 radiates the received power information transmission signal into space.

[0229] In step 6-5, the received power information transmission signal sent in step 6-4 is received by the received power information acquisition unit 65 and the receiver 25. The received power information acquisition unit 65 also obtains the reference element power P1 and the evaluation beam power P from the received signal. d Obtain it.

[0230] Next, in step ST6-6, the threshold calculation unit 66 calculates the nominal value W of the excitation coefficient for the evaluation beam. m and reference element power P1 and element electric field value E m Using the excitation error target value, evaluate the beam power P d The upper and lower threshold values ​​are calculated. Note that the method for calculating the upper and lower threshold values ​​is the same as in Embodiment 1, so the explanation of the calculation method is omitted.

[0231] In step ST6-7, the determination unit 67 evaluates the beam power P d and upper threshold P max and lower threshold P min The two are compared and evaluated. That is, the determination unit 67 evaluates the beam power P d The upper threshold P maxand lower threshold P min Determine if it is within the range. P min ≤P d ≤P max If this is the case, the determination unit 67 determines that the excitation error of each signal of the calibrated antenna element 2-m is smaller than the target excitation error value. On the other hand, P d <P min or P d >P max If so, the determination unit 67 determines that the excitation error of each signal of the calibrated antenna element 2-m is greater than the target excitation error value.

[0232] ***Explanation of the effects of the embodiment*** According to this embodiment, even when the array antenna is mounted on an artificial satellite, it is possible to easily determine whether the excitation error after calibration is smaller than the target value.

[0233] Specifically, in the array antenna diagnostic system according to Embodiment 6, the reference element power and evaluation beam power of the DBF antenna are calculated based on a diagnostic signal transmitted from the diagnostic antenna, using a pre-stored excitation coefficient for reference element evaluation and a calibrated excitation coefficient for the evaluation beam. Furthermore, received power information notifying the calculated reference element power and evaluation beam power is transmitted and received via space. In addition, the received power threshold of the evaluation beam is calculated using the reference element power, a pre-stored pre-calibrated excitation coefficient for the evaluation beam, a pre-stored element electric field value which is the pass-through characteristic between each antenna element and the diagnostic antenna, and a pre-stored excitation error target value. Then, it is evaluated whether the evaluation beam power is within the range defined by the received power threshold. As a result, even in a configuration where most of the components that perform calculation processing in the diagnosis are provided separately from the array antenna being diagnosed, the same effects as in Embodiment 1 can be obtained.

[0234] The above description concerns an array antenna diagnostic system in which the threshold calculation unit calculates the received power threshold using the reference element power, element electric field value, and excitation error target value. Since the array antenna 60 to be diagnosed is mounted on an artificial satellite and the diagnostic antenna device 7 is installed on the ground, the diagnostic antenna 8 is installed in a position that can be considered to be in the so-called far field of the array antenna 60. Therefore, similar to the array antenna diagnostic system of Embodiment 3, the external device 61 may be configured to include an element pattern information storage unit 31 and an antenna directivity error storage unit 32, and to include a threshold calculation unit 33 instead of a threshold calculation unit 66. In such a configuration, the external device 61 can calculate the received power threshold of the evaluation beam using the pre-stored excitation coefficient for the evaluation beam before calibration, the pre-stored element electric field value which is the pass-through characteristic between each antenna element and the diagnostic antenna, the pre-stored excitation error target value, the pre-stored information on the shape of the element pattern, and the pre-stored assumed value of the antenna directivity error. This makes it possible to obtain the same effects as in Embodiment 1, even when there is an antenna directivity error, in a configuration where most of the components that perform calculation processing in the diagnosis are provided separately from the array antenna being diagnosed.

[0235] ***summary*** The above embodiments 1 to 6 mainly described the following features.

[0236] In an array antenna diagnostic system that determines whether the difference in pass characteristics between antenna element systems of an array antenna having a digital beamforming function and equipped with a receiver or transmitter for each of multiple antenna elements is less than or equal to a predetermined magnitude, A diagnostic antenna that transmits or receives high-frequency signals for diagnostic purposes, An excitation coefficient storage unit stores a reference element evaluation excitation coefficient for evaluating the signal of an antenna element that serves as a diagnostic reference among the aforementioned antenna elements, an evaluation beam excitation coefficient for forming an evaluation beam, and an evaluation beam excitation coefficient calibrated by separately stored calibration values. A power calculation unit that calculates the reference element power, which is the power of the received signal based on the reference element evaluation excitation coefficient stored in the excitation coefficient storage unit, and the evaluation beam power, which is the power of the received signal based on the calibrated evaluation beam excitation coefficient stored in the excitation coefficient storage unit. An excitation error target value storage unit stores the excitation error target value, which is the target value of the difference in transmission characteristics between antenna element systems. An element electric field value storage unit stores the element electric field value, which is the pass-through characteristic between each antenna element and the diagnostic antenna. A threshold calculation unit calculates a received power threshold that indicates the upper and lower limits of the evaluation beam power, using the excitation coefficient for the evaluation beam, the reference element power, the element electric field value stored in the element electric field value storage unit, and the excitation error target value stored in the excitation error target value storage unit. A determination unit that evaluates whether the evaluation beam power calculated by the power calculation unit is within the range defined by the received power threshold calculated by the threshold calculation unit, An array antenna diagnostic system equipped with this system.

[0237] The excitation error target value is the standard deviation of the amplitude difference and phase difference of the pass-through characteristic difference between the antenna element systems, M is the number of antenna elements, and W is the excitation coefficient for the evaluation beam and the element electric field value for the mth antenna element. m and E m E1 is the element electric field value of the reference antenna element, and σ is the standard deviation of the amplitude difference and phase difference of the pass-through characteristic difference between the antenna element systems, which is the target excitation error value. Δ and σ δ When the power of the reference element is P1, The excitation coefficient for the evaluation beam has the relationship expressed in equation 32, The power calculation unit calculates the upper limit value P, which is the received power threshold, based on equations 33 to 37. max and lower limit P min A diagnostic system for calculating array antennas.

[0238]

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[0240]

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[0244] When the aperture diameter of the array antenna is D and the wavelength of the high-frequency signal for diagnosis is λ, the distance R between the array antenna and the diagnostic antenna is R > 2 × D. 2 It is located at a position that satisfies the condition / λ, The element field value stored in the element field value storage unit is a far-field element pattern that shows the radiation directivity in the direction of the diagnostic antenna as seen from each antenna element. Furthermore, the system includes an element pattern information storage unit that stores information regarding the shape of the far-field element pattern, It includes an antenna direction error storage unit that stores an estimated value of the antenna direction error, which is the error from the design value of the direction of the diagnostic antenna as seen from the array antenna. The threshold calculation unit further calculates the received power threshold using the information regarding the shape of the far-field element pattern stored in the element pattern information storage unit and the assumed value of the antenna directivity error stored in the antenna directivity error storage unit. Array antenna diagnostic system.

[0245] The aforementioned excitation error target value is the standard deviation of the amplitude difference and phase difference of the pass-through characteristic difference between the antenna element systems. The information relating to the shape of the far-field element pattern includes parameters that define the beam width, parameters indicating the spacing of the beam peaks in the θ and φ directions of the far-field element patterns of adjacent antenna elements, and coefficients indicating the slope of the phase distribution in the θ and φ directions. The assumed value of the antenna directivity error is the standard deviation of the antenna directivity error in the θ direction and the φ direction, M is the number of antenna elements, and W is the excitation coefficient for the evaluation beam and the element electric field value for the m-th antenna element, respectively. m and E m E1 is the element electric field value of the reference antenna element, and σ is the standard deviation of the amplitude difference and phase difference of the pass-through characteristic difference between the antenna element systems, which is the target excitation error value. Δ and σ δ P1 is the power of the reference element, b is the parameter that defines the beam width, and d is the parameter that indicates the spacing in the beam peak direction in the θ and φ directions. θ and d φ a is a coefficient that indicates the slope of the phase distribution in the θ direction and the φ direction. θ and a φ When that is the case, The excitation coefficient for the evaluation beam has a relationship expressed in equation 38, The power calculation unit calculates the upper limit value P, which is the received power threshold, based on equations 39 to 45. max and lower limit P min A diagnostic system for calculating array antennas.

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[0254] The array antenna is a receiving antenna in which each antenna element is equipped with a receiver, and further, The excitation coefficient storage unit and the power calculation unit, A received power information transmission circuit generates a signal for transmitting information regarding the reference element power and evaluation beam power calculated by the power calculation unit, The system includes a received power information transmitting antenna that transmits signals generated by the received power information transmitting circuit, moreover, A received power information receiving antenna that receives signals transmitted from the received power information transmitting antenna, A received power information acquisition unit acquires information regarding the reference element power and evaluation beam power from the signal received by the received power information receiving antenna, A second excitation coefficient storage unit that stores the same excitation coefficient as the aforementioned excitation coefficient storage unit, An external device comprising the excitation error target value storage unit, the element electric field value storage unit, the threshold calculation unit, and the determination unit, An array antenna diagnostic system equipped with this system.

[0255] The array antenna is a receiving antenna in which each antenna element is equipped with a receiver, and further, The excitation coefficient storage unit and the power calculation unit, A received power information transmission circuit generates a signal for transmitting information regarding the reference element power and evaluation beam power calculated by the power calculation unit, The system includes a received power information transmitting antenna that transmits signals generated by the received power information transmitting circuit, moreover, A received power information receiving antenna that receives signals transmitted from the received power information transmitting antenna, A received power information acquisition unit acquires information regarding the reference element power and evaluation beam power from the signal received by the received power information receiving antenna, A second excitation coefficient storage unit that stores the same excitation coefficient as the aforementioned excitation coefficient storage unit, An external device comprising the excitation error target value storage unit, the element electric field value storage unit, the element pattern information storage unit, the antenna directivity error storage unit, the threshold calculation unit, and the determination unit, An array antenna diagnostic system equipped with this system.

[0256] In an array antenna diagnostic system that determines whether the difference in pass characteristics between antenna element systems of an array antenna having a digital beamforming function and equipped with a receiver for each of multiple antenna elements is less than or equal to a predetermined magnitude, A diagnostic signal generation circuit that generates high-frequency signals for diagnosis, A diagnostic signal distribution circuit that distributes the high-frequency signals generated by the aforementioned diagnostic signal generation circuit, The high-frequency signals distributed by the diagnostic signal distribution circuit are input to a diagnostic signal input circuit provided on the signal line connecting each of the antenna elements and the receiver, A diagnostic signal extraction unit extracts a diagnostic signal from the signals received by each of the aforementioned receivers, An excitation coefficient storage unit stores a reference element evaluation excitation coefficient for evaluating the signal of an antenna element that serves as a diagnostic reference among the aforementioned antenna elements, an evaluation excitation coefficient for generating an evaluation signal, and an evaluation excitation coefficient calibrated by separately stored calibration values. A power calculation unit calculates the following: reference element power, which is the power of a signal based on the diagnostic signal extracted by the diagnostic signal extraction unit and the reference element evaluation excitation coefficient stored in the excitation coefficient storage unit; and evaluation power, which is the power of a signal based on the diagnostic signal extracted by the diagnostic signal extraction unit and the calibrated evaluation excitation coefficient stored in the excitation coefficient storage unit. An excitation error target value storage unit stores the excitation error target value, which is the target value of the difference in transmission characteristics between antenna element systems. The diagnostic signal generation circuit and the pass-through characteristic value storage unit store the pass-through characteristic values ​​between each receiver, A threshold calculation unit calculates a received power threshold that indicates the upper and lower limits of the evaluation power, using the evaluation excitation coefficient stored in the excitation coefficient storage unit, the reference element power calculated by the power calculation unit, the pass-through characteristic value stored in the pass-through characteristic value storage unit, and the excitation error target value stored in the excitation error target value storage unit. A determination unit that evaluates whether the evaluation power calculated by the power calculation unit is within the range defined by the received power threshold calculated by the threshold calculation unit, An array antenna diagnostic system equipped with this system.

[0257] In an array antenna diagnostic system that determines whether the difference in transmission characteristics between antenna element systems of an array antenna having a transmitter for each of multiple antenna elements and a digital beamforming function is less than or equal to a predetermined magnitude, An excitation coefficient storage unit stores a reference element evaluation excitation coefficient for evaluating the signal of an antenna element that serves as a diagnostic reference among the aforementioned antenna elements, an evaluation excitation coefficient for generating an evaluation signal, and an evaluation excitation coefficient calibrated by separately stored calibration values. A diagnostic signal input unit generates a digital signal for diagnosis based on each excitation coefficient stored in the excitation coefficient storage unit and inputs it to each transmitter. A distribution circuit is provided on the signal line connecting each of the aforementioned antenna elements to the transmitter, which splits the high-frequency signal propagating through the signal line into two, and outputs one of the split signals to each antenna element. A combining circuit that combines the other signal from among the signals distributed by each of the aforementioned distribution circuits, A diagnostic signal receiver that receives the high-frequency signal synthesized by the aforementioned synthesis circuit, A diagnostic signal extraction unit extracts a diagnostic signal from the signal received by the diagnostic signal receiver, A power calculation unit calculates the following: a reference element power, which is the power of the signal extracted by the diagnostic signal extraction unit, generated in the diagnostic signal input unit based on the excitation coefficient of the reference element evaluation excitation coefficient or the calibrated evaluation excitation coefficient stored in the excitation coefficient storage unit; and an evaluation power, which is the power of the signal extracted by the diagnostic signal extraction unit, generated in the diagnostic signal input unit based on the excitation coefficient of the calibrated evaluation excitation coefficient stored in the excitation coefficient storage unit; An excitation error target value storage unit stores the excitation error target value, which is the target value of the difference in transmission characteristics between antenna element systems. A pass-through characteristic value storage unit that stores the pass-through characteristic value between each of the distribution circuits and the receiver, A threshold calculation unit calculates a received power threshold that indicates the upper and lower limits of the evaluation power, using the evaluation excitation coefficient stored in the excitation coefficient storage unit, the reference element power calculated by the power calculation unit, the pass-through characteristic value stored in the pass-through characteristic value storage unit, and the excitation error target value stored in the excitation error target value storage unit. A determination unit that evaluates whether the evaluation power calculated by the power calculation unit is within the range defined by the received power threshold calculated by the threshold calculation unit, An array antenna diagnostic system equipped with this system.

[0258] The excitation error target value is the standard deviation of the amplitude difference and phase difference of the pass-through characteristic difference between the antenna element systems, Let M be the number of antenna elements, and W be the evaluation excitation coefficient for the mth antenna element. m, the pass-through characteristic value between the diagnostic signal generation circuit and the receiver connected to the mth antenna element, or the pass-through characteristic value between the distribution circuit connected to the mth antenna element and the diagnostic signal receiver is T m T1 is the pass-through characteristic value between the diagnostic signal generation circuit and the receiver connected to the reference antenna element, or the pass-through characteristic value between the distribution circuit connected to the reference antenna element and the diagnostic signal receiver, and σ is the standard deviation of the amplitude difference and phase difference of the pass-through characteristic difference between the antenna element systems, which is the excitation error target value. Δ and σ δ When the power of the reference element is P1, The aforementioned evaluation excitation coefficient has a relationship expressed in Equation 46, The power calculation unit calculates the upper limit value P, which is the received power threshold, based on equations 47 to 51. max and lower limit P min A diagnostic system for calculating array antennas.

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[0265] An array antenna calibration system having one of the array antenna diagnostic systems described above, which determines whether or not to calibrate the array antenna based on the evaluation result of the determination unit.

[0266] Although embodiments 1 to 6 have been described above, two or more of these embodiments may be combined and implemented. Alternatively, one of these embodiments may be partially implemented. Alternatively, two or more of these embodiments may be partially combined and implemented. Furthermore, the configurations and procedures described in these embodiments may be modified as needed.

[0267] ***Hardware Configuration Description*** Here, we will explain the hardware configuration of the diagnostic device 100.

[0268] Figure 13 shows an example of the configuration of the diagnostic device 100 according to this embodiment. The diagnostic device 100 according to this embodiment is implemented by a computer. The operating procedure of the diagnostic device 100 corresponds to the diagnostic method.

[0269] The diagnostic device 100 includes, as hardware, a processor 901, a main memory 902, an auxiliary memory 903, and a communication device 904. Furthermore, the power calculation unit 10, threshold calculation unit 13, and determination unit 14, which are functional components of the diagnostic device 100, are implemented, for example, by a program. In the following explanation, we will use the power calculation unit 10, threshold calculation unit 13, and determination unit 14 described in Embodiment 1 as examples. The following explanation also applies to the power calculation unit 26, threshold calculation unit 28, and determination unit 29 described in Embodiment 2. Similarly, the following explanation also applies to the threshold calculation unit 33 described in Embodiment 3. Similarly, the following explanation also applies to the power calculation unit 46, threshold calculation unit 48, and determination unit 49 described in Embodiment 4. Similarly, the following explanation also applies to the power calculation unit 56, threshold calculation unit 58, and determination unit 59 described in Embodiment 5. Similarly, the following explanation also applies to the threshold calculation unit 66 and determination unit 67 described in Embodiment 6.

[0270] The auxiliary storage device 903 stores programs that implement the functions of the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14. These programs are loaded from the auxiliary storage device 903 into the main memory device 902. Then, the processor 901 executes these programs to perform the operations of the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14. Figure 13 schematically shows the state in which the processor 901 is executing a program that implements the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14. The input / output devices 905 include a mouse, keyboard, recording medium reader, recording medium writer, display, etc.

[0271] The processor 901 shown in Figure 13 is an integrated circuit (IC) that performs processing. It is a circuit. Processor 901 includes components such as a CPU (Central Processing Unit) and a DSP (Digital Signal Processor). The main memory 902 shown in Figure 13 is RAM (Random Access Memory). The auxiliary storage device 903 shown in Figure 13 includes ROM (Read Only Memory), flash memory, HDD (Hard Disk Drive), etc. The communication device 904 shown in Figure 13 is an electronic circuit that performs data communication processing. The communication device 904 is, for example, a communication chip or a NIC (Network Interface Card).

[0272] Furthermore, the auxiliary storage device 903 also stores the OS (Operating System). Then, at least a portion of the OS is executed by processor 901. The processor 901 executes a program that implements the functions of the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14 while executing at least a part of the OS. Processor 901 executes the OS, handling task management, memory management, file management, communication control, and other functions. Furthermore, at least one of the information, data, signal values, and variable values ​​indicating the processing results of the power calculation unit 10, threshold calculation unit 13, and determination unit 14 is stored in at least one of the main memory 902, auxiliary memory 903, registers in the processor 901, and cache memory. Furthermore, the programs that implement the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14 may be stored on a portable recording medium such as a magnetic disk, flexible disk, optical disk, compact disk, Blu-ray® disc, or DVD. The portable recording medium containing the programs that implement the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14 may also be distributed.

[0273] Furthermore, at least one of the "units" in the power calculation unit 10, threshold calculation unit 13, and determination unit 14 may be read as "circuit," "process," "procedure," "process," or "circuitry." Furthermore, the diagnostic device 100 may be implemented by a processing circuit. Examples of processing circuits include logic ICs, GAs (Gate Arrays), ASICs (Application Specific Integrated Circuits), and FPGAs (Field-Programmable Gate Arrays). In this case, the power calculation unit 10, the threshold calculation unit 13, and the determination unit 14 are each implemented as part of a processing circuit. In this specification, the higher-level concept encompassing both the processor and the processing circuit is referred to as "processing circuitry." In other words, a processor and a processing circuit are specific examples of "processing circuits," respectively.

[0274] Finally, the various aspects of this disclosure are summarized below as an appendix. (Note 1) A power calculation unit calculates either the received power when a signal is received by a reference element system, which is an antenna element system selected from a plurality of antenna element systems, each containing an antenna element, or the received power when a signal transmitted from the reference element system is received, as the reference element power, and calculates either the received power when a signal is received by the plurality of antenna element systems including the reference element system or the received power when a signal transmitted from the plurality of antenna element systems including the reference element system is received, as the diagnostic power. A threshold calculation unit calculates an upper and lower threshold for the diagnostic power using the reference element power and an excitation error target value, which is a target value for the excitation error between antenna element systems. A diagnostic device having a determination unit that determines whether the diagnostic power is within the range of the upper limit threshold and the lower limit threshold. (Note 2) The determination unit, The diagnostic device according to Appendix 1, which determines that the excitation error between antenna element systems is smaller than the excitation error target value when the diagnostic power is within the range of the upper limit threshold and the lower limit threshold. (Note 3) The aforementioned multiple antenna element systems are included in an array antenna. The power calculation unit, The received power when a signal transmitted from an external antenna, which is an antenna outside the aforementioned array antenna, is received by the reference element system is calculated as the reference element power. The diagnostic device according to Appendix 1, which calculates the received power when a signal transmitted from the external antenna is received by the plurality of antenna element systems as the diagnostic power. (Note 4) The aforementioned multiple antenna element systems are included in an array antenna. The power calculation unit, The received power when the signal transmitted from the aforementioned reference element system is received by an external antenna, which is an antenna outside the array antenna, is calculated as the reference element power. The diagnostic device according to Appendix 1, which calculates the received power when the signals transmitted from the plurality of antenna element systems are received by the external antenna as the diagnostic power. (Note 5) The threshold calculation unit, A diagnostic device according to Appendix 3 or 4 that calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value between the external antenna and each of the multiple antenna elements included in the multiple antenna element system, and the nominal value of the excitation coefficient of the multiple antenna element system. (Note 6) The threshold calculation unit, A diagnostic device according to Appendix 5 that calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value, the nominal value of the excitation coefficient, the element pattern of each of the plurality of antenna elements, and the directional error of each of the plurality of antenna elements to the external antenna. (Note 7) The aforementioned plurality of antenna element systems are included in an array antenna having a signal generation unit that generates signals and transmits the generated signals. The power calculation unit, The received power when the signal transmitted from the signal generation unit is received by the reference element system is calculated as the reference element power. The diagnostic device according to Appendix 1, which calculates the received power when the signal transmitted from the signal generation unit is received by the plurality of antenna element systems as the diagnostic power. (Note 8) The threshold calculation unit, The diagnostic device according to Appendix 7, which calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value between the signal generation unit and each of the plurality of antenna element systems, and the nominal value of the excitation coefficient of the plurality of antenna element systems. (Note 9) The aforementioned plurality of antenna element systems are included in an array antenna having a receiver that receives signals. The power calculation unit, The received power when the signal transmitted from the reference element system is received by the receiver is calculated as the reference element power. The diagnostic device according to Appendix 1, which calculates the received power when the signals transmitted from the plurality of antenna element systems are received by the receiver as the diagnostic power. (Note 10) The threshold calculation unit, The diagnostic device according to Appendix 9, which calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value between the receiver and each of the plurality of antenna element systems, and the nominal value of the excitation coefficient of the plurality of antenna element systems. (Note 11) The power calculation unit is included in the array antenna which includes the plurality of antenna element systems. The threshold calculation unit and the determination unit are included in the diagnostic device described in Appendix 1, which is an external device outside the array antenna. (Note 12) The aforementioned array antenna is mounted on an artificial satellite, The aforementioned external device is a diagnostic device as described in Appendix 11, which is installed on the ground. (Note 13) The threshold calculation unit, The diagnostic device according to Appendix 1, which uses, as the excitation error target value, the standard deviation of the amplitude error and phase error of the signals between antenna element systems, the variance of the amplitude error and phase error of the signals between antenna element systems, or the variance of the integrated error obtained by combining the amplitude error and phase error of the signals between antenna element systems. (Note 14) The computer calculates either the received power when a signal is received by a reference element system, which is an antenna element system selected from a plurality of antenna element systems, each containing an antenna element, or the received power when a signal transmitted from the reference element system is received, as the reference element power. It then calculates either the received power when a signal is received by the plurality of antenna element systems including the reference element system, or the received power when a signal transmitted from the plurality of antenna element systems including the reference element system is received, as the diagnostic power. The computer calculates the upper and lower threshold values ​​for the diagnostic power using the reference element power and the excitation error target value, which is the target value of the excitation error between the antenna element systems. A diagnostic method in which the computer determines whether the diagnostic power is within the range of the upper limit threshold and the lower limit threshold. [Explanation of Symbols]

[0275] 1 Array antenna, 2-1 Antenna element, 2-2 Antenna element, 2-M Antenna element, 3-1 Receiver, 3-2 Receiver, 3-M Receiver, 4 Received DBF signal processing unit, 5 Excitation coefficient storage unit, 6 Output terminal, 7 Diagnostic antenna device, 8 Diagnostic antenna, 9 Diagnostic signal generation circuit, 10 Power calculation unit, 11 Excitation error target value storage unit, 12 Element electric field value storage unit, 13 Threshold calculation unit, 14 Judgment unit, 20 Array antenna, 21-1 Transmitter, 21-2 Transmitter, 21-M Transmitter, 22 Transmitting DBF signal processing unit, 23 Input terminal, 24 Diagnostic antenna device, 25 Receiver, 6 Power calculation unit, 27 Second excitation coefficient storage unit, 28 Threshold calculation unit, 29 Judgment unit, 30 Array antenna, 31 Element pattern information storage unit, 32 Antenna directivity error storage unit, 33 Threshold calculation unit, 40 Array antenna, 41-1 Diagnostic signal input circuit, 41-2 Diagnostic signal input circuit, 41-M Diagnostic signal input circuit, 42 Diagnostic signal generation circuit, 43 Distribution circuit, 44 Diagnostic signal extraction unit, 45 Diagnostic excitation coefficient storage unit, 46 Power calculation unit, 47 Pass-through characteristic value storage unit, 48 Threshold calculation unit, 49 Judgment unit, 50 Array antenna, 51 Diagnostic signal input unit, 52-1~52-M Second distribution circuit, 53 Diagnostic excitation coefficient storage unit, 54 Synthesis circuit, 55 Diagnostic signal extraction unit, 56 Power calculation unit, 57 Pass-through characteristic value storage unit, 58 Threshold calculation unit, 59 Judgment unit, 60 Array antenna, 61 External device, 62 Received power information transmission circuit, 63 Received power information transmission antenna, 64 Received power information receiving antenna, 65 Received power information acquisition unit, 66 Threshold calculation unit, 67 determination unit, 901 processor, 902 main memory, 903 auxiliary memory, 904 communication device.

Claims

1. A power calculation unit calculates either the received power when a signal is received by a reference element system, which is an antenna element system selected from a plurality of antenna element systems, each containing an antenna element, or the received power when a signal transmitted from the reference element system is received, as the reference element power, and calculates either the received power when a signal is received by the plurality of antenna element systems including the reference element system or the received power when a signal transmitted from the plurality of antenna element systems including the reference element system is received, as the diagnostic power. A threshold calculation unit calculates an upper and lower threshold for the diagnostic power using the reference element power and an excitation error target value, which is a target value for the excitation error between antenna element systems. A diagnostic device having a determination unit that determines whether the diagnostic power is within the range of the upper limit threshold and the lower limit threshold.

2. The determination unit, The diagnostic device according to claim 1, which determines that the excitation error between antenna element systems is smaller than the excitation error target value when the diagnostic power is within the range of the upper threshold and the lower threshold.

3. The aforementioned multiple antenna element systems are included in an array antenna. The power calculation unit, The received power when a signal transmitted from an external antenna, which is an antenna outside the aforementioned array antenna, is received by the reference element system is calculated as the reference element power. The diagnostic device according to claim 1, wherein the received power when a signal transmitted from the external antenna is received by the plurality of antenna element systems is calculated as the diagnostic power.

4. The aforementioned multiple antenna element systems are included in an array antenna. The power calculation unit, The received power when the signal transmitted from the aforementioned reference element system is received by an external antenna, which is an antenna outside the array antenna, is calculated as the reference element power. The diagnostic device according to claim 1, wherein the received power when the signals transmitted from the plurality of antenna element systems are received by the external antenna is calculated as the diagnostic power.

5. The threshold calculation unit, The diagnostic device according to claim 3 or 4, which calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value between the external antenna and each of the plurality of antenna elements included in the plurality of antenna element systems, and the nominal value of the excitation coefficient of the plurality of antenna element systems.

6. The threshold calculation unit, The diagnostic device according to claim 5, which calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value, the nominal value of the excitation coefficient, the element pattern of each of the plurality of antenna elements, and the directional error of each of the plurality of antenna elements to the external antenna.

7. The aforementioned plurality of antenna element systems are included in an array antenna having a signal generation unit that generates signals and transmits the generated signals. The power calculation unit, The received power when the signal transmitted from the signal generation unit is received by the reference element system is calculated as the reference element power. The diagnostic device according to claim 1, wherein the received power when the signal transmitted from the signal generation unit is received by the plurality of antenna element systems is calculated as the diagnostic power.

8. The threshold calculation unit, The diagnostic device according to claim 7, which calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value between the signal generation unit and each of the plurality of antenna element systems, and the nominal value of the excitation coefficient of the plurality of antenna element systems.

9. The aforementioned plurality of antenna element systems are included in an array antenna having a receiver that receives signals. The power calculation unit, The received power when the signal transmitted from the reference element system is received by the receiver is calculated as the reference element power. The diagnostic device according to claim 1, wherein the received power when the signals transmitted from the plurality of antenna element systems are received by the receiver is calculated as the diagnostic power.

10. The threshold calculation unit, The diagnostic device according to claim 9, which calculates the upper limit threshold and the lower limit threshold using the reference element power, the excitation error target value, the pass-through characteristic value between the receiver and each of the plurality of antenna element systems, and the nominal value of the excitation coefficient of the plurality of antenna element systems.

11. The power calculation unit is included in the array antenna which includes the plurality of antenna element systems. The diagnostic device according to claim 1, wherein the threshold calculation unit and the determination unit are included in an external device outside the array antenna.

12. The aforementioned array antenna is mounted on an artificial satellite, The diagnostic device according to claim 11, wherein the external device is installed on the ground.

13. The threshold calculation unit, The diagnostic device according to claim 1, wherein the excitation error target value is one of the following: the standard deviation of the amplitude error and phase error of the signals between antenna element systems, the variance of the amplitude error and phase error of the signals between antenna element systems, or the variance of the integrated error obtained by combining the amplitude error and phase error of the signals between antenna element systems.

14. The computer calculates either the received power when a signal is received by a reference element system, which is an antenna element system selected from a plurality of antenna element systems, each containing an antenna element, or the received power when a signal transmitted from the reference element system is received, as the reference element power. It then calculates either the received power when a signal is received by the plurality of antenna element systems including the reference element system, or the received power when a signal transmitted from the plurality of antenna element systems including the reference element system is received, as the diagnostic power. The computer calculates the upper and lower threshold values ​​for the diagnostic power using the reference element power and the excitation error target value, which is the target value of the excitation error between the antenna element systems. A diagnostic method in which the computer determines whether the diagnostic power is within the range of the upper limit threshold and the lower limit threshold.

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