Electric wave type sensor

Abstract

To provide an electric wave type sensor capable of determining movement of an object appropriately even if the speed of the object changes.SOLUTION: An electric wave type sensor 10 comprises: a transmission antenna 11 for transmitting electric waves and a reception antenna 12 for receiving the electric waves reflected by an object; a phase detection section 14 for outputting an I signal, and a Q signal different from the I signal by 90 degrees in terms of a phase on the basis of signals from the transmission antenna 11 and the reception antenna 12; an arithmetic processing section 162 for acquiring multiple voltage values of the I signal and multiple voltage values of the Q signal at a predetermined time interval from the phase detection section 14 and performing arithmetic processing on the basis of the multiple acquired voltage values; and a determination section 163 for determining movement of the object on the basis of a result of the arithmetic processing of the arithmetic processing section 162.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a radio wave sensor, and more particularly to a radio wave sensor that detects approaching or moving away from a measurement object. [Background technology]

[0002] Conventionally, a quadrature detection circuit is used to output two IQ signals with a phase difference of 90 degrees, and the direction of movement of a moving object is detected by processing the IQ signals. The two IQ signals are output so that a phase difference of 90 degrees is obtained between the outputs.

[0003] For example, cited documents 1 and 2 disclose a technique in which either the I signal or the Q signal is shifted by approximately 90 degrees relative to the other to superimpose them, and then a moving average of the product is calculated. In cited documents 1 and 2, whether an object is approaching or moving away from a sensor is determined depending on the sign of the moving average. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5996385 [Patent Document 2] Japanese Patent Application Publication No. 2023-140427 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there are cases where detection of objects over a wide range of velocities is required. The actual Doppler frequency also has a wide bandwidth, corresponding to the wide range of velocities of the objects relative to the sensor. Therefore, when the range of velocities of the objects is wide, even if a specific frequency is determined and either the I signal or the Q signal is shifted by 90 degrees as in the case of the cited documents 1 and 2, the I signal and the Q signal may not be properly overlapped, and movement relative to the sensor may not be properly identified.

[0006] In order to solve the above-mentioned problems, an object of the present disclosure is to provide a radio wave sensor that can appropriately determine the movement of an object even when the speed of the object changes. [Means for solving the problem]

[0007] In order to achieve the above objective, the radio wave sensor disclosed herein employs a method in which the voltage values ​​of two signals with different phases output from a phase detection circuit are acquired at predetermined time intervals, and arithmetic processing is performed based on the acquired multiple voltage values.

[0008] Specifically, the radio wave sensor of the present disclosure includes: an antenna that transmits radio waves and receives the radio waves reflected by an object; a phase detection circuit that outputs a first signal and a second signal that is 90 degrees out of phase with the first signal based on a signal from the antenna; a calculation processing unit that acquires a plurality of voltage values ​​of the first signal and a plurality of voltage values ​​of the second signal from the phase detection circuit at predetermined time intervals and performs calculation processing based on the acquired plurality of voltage values; a determination unit that determines movement of an object based on a result of the arithmetic processing by the arithmetic processing unit; Equipped with.

[0009] This allows the movement of the object relative to the radio wave sensor to be appropriately determined based on the voltage value of the signal that fluctuates in response to the actual movement of the object. In particular, the present disclosure provides a method for identifying approach and departure that does not invert over a wider frequency range.

[0010] The arithmetic processing unit subtracts a product of a voltage value of the second signal at a first time point and a voltage value of the first signal at a second time point, the voltage value being different from the first time point, from the product of a voltage value of the first signal at the first time point and a voltage value of the second signal at the second time point, the second time point being different from the first time point; The determination unit may determine the moving direction of the object based on a result of the subtraction performed by the calculation processing unit.

[0011] This makes it possible to appropriately determine the moving direction (approach or departure) of the object relative to the radio wave sensor using the subtraction result.

[0012] The arithmetic processing unit executes the subtraction a plurality of times, The determination unit may determine the moving direction of the object based on results of the subtraction performed multiple times by the calculation processing unit.

[0013] This makes it possible to appropriately determine whether an object is approaching or leaving the radio wave sensor.

[0014] Furthermore, the determination unit may determine that the object is moving in a direction toward or away from the antenna when the number of times the result of the subtraction exceeds a predetermined threshold exceeds a predetermined number of times.

[0015] This makes it possible to appropriately determine whether an object is approaching or leaving the radio wave sensor.

[0016] Furthermore, the calculation processing unit adds a product of a voltage value of the first signal at the first time point and a voltage value of the second signal at the second time point and a product of a voltage value of the second signal at the first time point and a voltage value of the first signal at the second time point, The determination unit may not determine that an object is present when the result of the addition is greater than the result of the subtraction.

[0017] According to this, by combining the results of the calculation processes, it is possible to appropriately determine whether an object is approaching or leaving the radio wave sensor.

[0018] The signal processing device may further include a spike removal unit that replaces a voltage value exceeding a predetermined threshold with 0 when the voltage value of the first signal at the first time point, the voltage value of the second signal at the first time point, the voltage value of the first signal at the second time point, and the voltage value of the second signal at the second time point each exceed a predetermined threshold.

[0019] This makes it possible to properly determine whether an object is approaching or leaving the radio wave sensor while effectively removing spikes.

[0020] The first signal and the second signal may be Doppler IQ signals.

[0021] The above disclosures can be combined as much as possible. [Effects of the Invention]

[0022] According to the present disclosure, it is possible to appropriately determine the movement of an object even when the speed of the object changes. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram illustrating a configuration of a microwave Doppler detection device according to a first embodiment of the present disclosure. [Figure 2] 1A and 1B are diagrams illustrating detection of an object by a related radio wave sensor. [Figure 3] 10A and 10B are diagrams illustrating the relationship between an I signal and a Q signal when an object approaches or moves away from a radio wave sensor. [Figure 4] 1A and 1B are diagrams illustrating detection of an object by a related radio wave sensor. [Figure 5] 3A to 3C are diagrams illustrating an overview of signal processing of the radio wave sensor according to the first embodiment of the present disclosure. [Figure 6] 1 is a diagram illustrating a configuration of a signal processing circuit according to a first embodiment of the present disclosure. [Figure 7] 3A to 3C are diagrams illustrating a method for determining whether an object is approaching or leaving in signal processing according to the first embodiment of the present disclosure. [Figure 8] 4A to 4C are diagrams illustrating the effect of signal processing according to the first embodiment of the present disclosure. [Figure 9] FIG. 10 is a diagram illustrating the configuration of a signal processing circuit according to a second embodiment of the present disclosure. [Figure 10]FIG. 10 is a diagram illustrating the configuration of a signal processing circuit according to a third embodiment of the present disclosure. [Figure 11] FIG. 10 is a diagram illustrating the configuration of a signal processing circuit according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0025] (First embodiment) A microwave Doppler detection device 100 according to an embodiment of the present disclosure will be described with reference to FIGS.

[0026] [Outline of microwave Doppler detection device] FIG. 1 is a diagram illustrating the configuration of a microwave Doppler detection device 100. As shown in FIG. The microwave Doppler detection device 100 is a device that transmits microwaves, detects reflected waves from a measurement object such as a moving object, determines the position and movement of the measurement object, and outputs the results of the determination. The microwave Doppler detection device 100 is connected to an external device, and the external device functions based on a signal (determination result) from the microwave Doppler detection device 100. The microwave Doppler detection device 100 may also function as a non-contact switch.

[0027] Specifically, the radio wave sensor 10 of the present disclosure includes: a transmitting antenna 11 for transmitting radio waves, and a receiving antenna 12 for receiving the radio waves reflected by an object; a phase detector 14 that outputs an I signal and a Q signal that is 90 degrees out of phase with the I signal based on signals from a transmitting antenna 11 and a receiving antenna 12; a calculation processing unit 162 that acquires a plurality of voltage values ​​of the I signal and a plurality of voltage values ​​of the Q signal from the phase detection unit 14 at predetermined time intervals and performs calculation processing based on the acquired plurality of voltage values; a determination unit 163 that determines the movement of the object based on the result of the calculation processing by the calculation processing unit 162; Equipped with.

[0028] The microwave Doppler detection device 100 includes a radio wave sensor 10. The radio wave sensor 10 includes a transmitting antenna 11, a receiving antenna 12, an oscillator 13, a phase detector 14, an AD converter (A / D converter (Analog Digital Converter)) 15, and a signal processing circuit 16. The transmitting antenna 11 and the receiving antenna 12 function as "antennas."

[0029] The radio wave sensor 10 is a Doppler sensor, and can detect the movement of an object based on the presence or absence of a Doppler signal based on the speed of the moving object relative to the radio wave sensor 10. The radio wave sensor 10 may be configured to be capable of detecting various user movements (for example, finger movements). The radio wave sensor 10 may also be configured to be capable of detecting movements other than those of a person's body.

[0030] The transmitting antenna 11 transmits microwaves to the outside. Specifically, a signal oscillated by an oscillator is transmitted from the transmitting antenna 11 as a transmission wave. The transmission wave from the transmitting antenna 11 is reflected by an object. The receiving antenna 12 receives the reflected wave reflected by the object.

[0031] The oscillator 13 outputs a portion of the oscillating signal to the phase detector 14 as a receiving-side local signal. The receiving-side local signal is split into two signals so that a phase difference of 90 degrees is obtained between the outputs. A signal related to the reflected wave received by the receiving antenna 12 is also input to the phase detector 14. Here, the phase difference between the transmitted wave and the received wave is a Doppler frequency corresponding to the moving speed of the target object. The phase detector 14 performs phase detection on the signal related to the reflected wave with respect to the receiving-side local signal, and outputs two Doppler I and Q signals that are 90 degrees out of phase with each other. In this embodiment, the phase detector 14 is a phase detection circuit for outputting two Doppler I and Q signals that are 90 degrees out of phase with each other. However, the phase detector 14 does not necessarily have to be a circuit; it is sufficient that the phase detector 14 is configured to output I and Q signals that are 90 degrees out of phase with each other. The I and Q signals are examples of a "first signal" or a "second signal." In the present disclosure, a phase difference of 90 degrees includes not only a case where the phase difference is exactly 90 degrees, but also a case where the phase difference is approximately 90 degrees.

[0032] [Outline of signal processing for radio wave sensors] Next, an overview of signal processing in the radio wave sensor 10 will be described with reference to FIG. 5. FIG. 5 is a diagram for explaining the overview of signal processing in the radio wave sensor 10. The radio wave sensor 10 includes, as signal processing components, a Doppler sensor circuit unit 101, a pair of high-pass filters 17A and 17B, a pair of amplifiers 18A and 18B, a pair of AD converters 15A and 15B, and a signal processing circuit 16. The Doppler sensor circuit unit 101 includes the above-mentioned transmitting antenna 11, receiving antenna 12, oscillator 13, and phase detector 14. As described above, the phase detector 14 outputs two Doppler I and Q signals that are 90 degrees out of phase with each other. Specifically, the Doppler I signal is input to the high-pass filter 17A, and the Doppler Q signal is input to the high-pass filter 17B. As such, in this embodiment, two high-pass filters 17, two amplifiers 18, and two AD converters 15 are provided corresponding to the Doppler I and Q signals.

[0033] The pair of high-pass filters 17A and 17B attenuate low frequencies corresponding to small movements. In this embodiment, the cutoff frequency of the pair of high-pass filters 17A and 17B is set to the Doppler center frequency, and the pair of high-pass filters 17A and 17B function to cut off low frequencies equal to or lower than the Doppler center frequency. In this embodiment, the low cutoff frequency of the pair of high-pass filters 17A and 17B is set to, for example, about 50 Hz. The pair of high-pass filters 17A and 17B output the filtered Doppler I and Q signals to the pair of amplifiers 18A and 18B.

[0034] The pair of amplifiers 18A and 18B amplify the Doppler I and Q signals from which the low frequency range has been removed by the pair of high-pass filters 17A and 17B, and output the amplified Doppler I and Q signals to the pair of AD converters 15A and 15B.

[0035] The pair of AD converters 15A and 15B samples the amplified Doppler I and Q signals at a sampling time of, for example, 1 / 8 period of the Doppler center frequency or less, and outputs the sampled Doppler I and Q signals to the signal processing circuit 16.

[0036] [Related radio wave sensors and their issues] Here, the detection of an object by the related radio wave sensor 20 and the problems involved will be described with reference to FIGS. 2 is a diagram illustrating the detection of an object by the radio wave sensor 20. The radio wave sensor 20 basically has the same configuration as the radio wave sensor 10, but differs mainly in its processing. Specifically, the radio wave sensor 20 has a transmitting antenna 11, a receiving antenna 12, an oscillator 13, and a phase detector 14.

[0037] Here, the correspondence relationship between the Doppler frequency from an object and the moving speed of the object when the object is moving will be explained. The Doppler frequency fd when the object is moving is expressed by the following equation.

number

[0038] where: fd: Doppler frequency (Hz) v: object's moving speed (m / s) f0: Transmitted wave frequency (Hz) c: Speed ​​of light 3×10^8(m / s) θ: the angle between the direction of movement of the object and the direction of observation For example, if the transmission frequency f0 is 24.15 GHz, the Doppler frequency fd of an object with a speed v of 2 m / s will be 322 Hz, and the Doppler frequency fd of an object with a speed v of 3 m / s will be 483 Hz.

[0039] In this way, since there is a predetermined relationship between the moving speed v (Doppler speed: vcosθ) of the object and the Doppler frequency fd, the radio wave sensor 20 executes processing according to the moving speed of the object (moving body).

[0040] Fig. 4(A) shows the relationship between the Doppler I and Q signals when an object moves in a predetermined manner to be detected. Specifically, Fig. 4(A) shows the relationship between the Doppler I and Q signals when an object approaches the radio wave sensor 20. The Q signal has a phase delay of 90 degrees with respect to the I signal.

[0041] As shown in FIG. 4(B), in the radio wave sensor 20, the waveform of either the I signal or the Q signal is shifted in time by 1 / 4 period of the set Doppler center frequency.

[0042] Next, as shown in Fig. 4(C), the radio wave sensor 20 calculates the product of the I signal and the Q signal after shifting one of them in time. Then, as shown in Fig. 4(D), the radio wave sensor 20 calculates the average value of the data from a certain time before the current time based on the data after the integration.

[0043] 3, the phase difference between the I signal and the Q signal differs by 180 degrees when an object approaches or moves away from the radio wave sensor 20. Therefore, the plus or minus sign of the calculated average value is reversed when an object approaches or moves away from the radio wave sensor 20. Based on this, the radio wave sensor 20 determines whether an object is approaching or moving away.

[0044] However, in the radio wave sensor 20, the Doppler center frequency is set in advance so that the I signal and Q signal overlap by temporally shifting the waveform of the I signal or Q signal at a specific point in time by 1 / 4 period. In other words, a specific frequency is determined and shifted by 90 degrees so that the I signal and Q signal overlap.

[0045] However, there are cases where detection of objects over a wide speed range is required. The actual Doppler frequency has a wide bandwidth corresponding to the wide speed range of the object relative to the radio wave sensor 20. Therefore, when the speed range of the object is wide, even if a specific frequency is determined and either the I signal or the Q signal is shifted by 90 degrees, as in the processing in the radio wave sensor 20, the I signal and the Q signal cannot be superimposed, and it is not possible to properly determine whether the object is approaching or leaving the radio wave sensor 20. Furthermore, if the phase difference between the I signal and the Q signal shifts by 180 degrees as the speed of the object changes, the calculation result of approach or leaving may be reversed, resulting in an erroneous detection of the actual moving direction of the object.

[0046] [Configuration and processing of signal processing circuit] Next, the processing and effects of the signal processing circuit 16 according to the first embodiment will be described with reference to Fig. 6 to Fig. 8. Fig. 6 is a diagram illustrating the configuration of the signal processing circuit 16. Fig. 7 is a diagram illustrating a method for determining whether an object is approaching or leaving in signal processing according to the first embodiment. Fig. 8 is a diagram illustrating the effects of signal processing according to the first embodiment.

[0047] To address the above-described problems, the signal processing circuit 16 in this embodiment performs arithmetic processing (described later) based on the voltage values ​​of the I and Q signals at time t1 and the voltage values ​​of the I and Q signals at time t2, which is different from time t1, to determine whether an object is approaching or moving away from the radio wave sensor 10. Time t1 is an example of a "first time point," and time t2 is an example of a "second time point."

[0048] in particular, The calculation processing unit 162 subtracts the product of the voltage value B of the Q signal at time t1 and the voltage value C of the I signal at time t2 from the product of the voltage value A of the I signal at time t1 and the voltage value D of the Q signal at time t2, which is different from time t1; The determination unit 163 determines the moving direction of the object based on the result of the subtraction performed by the calculation processing unit 162.

[0049] 6, the signal processing circuit 16 includes a pair of signal removal units 161A and 161B, an arithmetic processing unit 162, and a determination unit 163. In this embodiment, two signal removal units 161 are provided corresponding to the Doppler I and Q signals.

[0050] The outputs from the pair of AD converters 15A and 15B are input to a pair of signal removal units 161A and 161B. The pair of signal removal units 161A and 161B remove signals that exceed a positive upper threshold and signals that fall below a negative lower threshold. The upper threshold or lower threshold is set to a value that saturates the amplifier 18 or AD converter 15, or a value that is smaller than the maximum value of the AD converter 15 but is sufficiently larger than the value of the detection signal from the object to be measured.

[0051] Specifically, if there is a signal that exceeds the upper threshold and a signal that is below the lower threshold, the output data of that portion is replaced with 0. In this way, the signal removal unit 161 functions to remove the influence of large noise, such as a single noise that saturates AD conversion, before performing the arithmetic processing described below. The outputs from the pair of signal removal units 161A and 161B are input to the arithmetic processing unit 162.

[0052] The arithmetic processing unit 162 performs arithmetic processing based on the voltage values ​​of the I and Q signals at time t1 and the voltage values ​​of the I and Q signals at time t2, which is different from time t1. First, the arithmetic processing unit 162 samples the I and Q signals from the pair of signal removal units 161A and 161B at predetermined intervals.

[0053] 7, the arithmetic processing unit 162 designates the voltage value of the I signal at time t1 as A and the voltage value of the Q signal as B. Similarly, the arithmetic processing unit 162 designates the voltage value of the I signal at time t2 after time t1 as C and the voltage value of the Q signal as D. Note that A, B, C, and D include positive and negative signs.

[0054] Then, the calculation processing unit 162 subtracts the product of B and C from the product of A and D (subtraction process) and outputs the subtraction result P (=AD-BC) to the determination unit 163. This corresponds to extracting the imaginary part (numerator) of the division of a complex number where the voltage value of the I signal is the real part and the voltage value of the Q signal is the imaginary part for each time, as shown in the following formula.

number

[0055] The determination unit 163 determines whether the object is approaching or leaving the radio wave sensor 10 based on the subtraction result P. Specifically, the sign of the subtraction result P is reversed depending on whether the signal is rotating clockwise or counterclockwise on the IQ plane. A clockwise rotation of the signal corresponds to either the object's approach to or departure from the radio wave sensor 10, and a counterclockwise rotation of the signal corresponds to the other of the object's approach to or departure from the radio wave sensor 10. Therefore, the determination unit 163 can determine whether the object is approaching or leaving the radio wave sensor 10 based on the subtraction result P. Whether the clockwise or counterclockwise rotation of the signal corresponds to the object's approach or departure depends on the settings.

[0056] Furthermore, the higher the rotation speed (frequency), the larger the absolute value of the subtraction result P. This absolute value corresponds to the moving speed (velocity) of the object relative to the radio wave sensor 10. Therefore, the determination unit 163 can also calculate the moving speed (vcosθ) of the object relative to the radio wave sensor 10 from the absolute value of the subtraction result P.

[0057] 8, in the related prior art described above, when the actual frequency exceeds twice the reference frequency (Doppler center frequency), the approach / leave determination result is reversed. In other words, there is a possibility that the actual moving direction of the target object relative to the radio wave sensor 10 may be erroneously detected.

[0058] In contrast to this, in this embodiment, by using the subtraction result P as described above to determine approach or departure, even if the actual frequency exceeds twice the reference frequency, it is possible to appropriately determine whether the object is approaching or leaving the radio wave sensor 10. In other words, according to this embodiment, it is possible to obtain a method for identifying approach or departure that does not invert over a wider frequency range.

[0059] In principle, the sampling intervals of the I and Q signals are arbitrary, and the approach or departure of an object may be determined based on the I and Q signals for times t1 and t2 that are adjacent to each other at a predetermined interval. Alternatively, the approach or departure of an object may be determined based on the I and Q signals for two non-adjacent times among the time points that are spaced apart at a predetermined interval.

[0060] Furthermore, the sampling interval for the I and Q signals may be set to twice the frequency to be restored, taking into account the Nyquist frequency. For example, if sampling is performed at intervals of 1 msec, frequencies up to 500 Hz, half the frequency of 1 kHz corresponding to the sampling interval, can be accurately extracted.

[0061] (Second embodiment) Next, a signal processing circuit 26 according to a second embodiment of the present disclosure and its processing will be described with reference to Fig. 9. Fig. 9 is a diagram illustrating the configuration of the signal processing circuit 26 according to the second embodiment. The signal processing circuit 26 performs counting processing.

[0062] The signal processing circuit 26 includes a signal removal unit 161 and an arithmetic processing unit 162, similar to the signal processing circuit 16 according to the first embodiment. The signal processing circuit 26 also includes a determination unit 263 instead of the determination unit 163. The determination unit 263 includes a counter 263A.

[0063] in particular, The calculation processing unit 162 executes the subtraction multiple times, The determination unit 163 determines the moving direction of the object based on the results of the subtraction performed multiple times by the calculation processing unit 162. Also, The determination unit 163 determines that the object is moving in a direction approaching or moving away from the radio wave sensor 10 when the number of times the result of the subtraction exceeds the predetermined threshold value exceeds a predetermined number of times.

[0064] The arithmetic processing unit 162 calculates the subtraction result P multiple times and sends it to the determination unit 263 each time it calculates the subtraction result P. For example, the arithmetic processing unit 162 calculates the subtraction result P from the voltage values ​​of the I and Q signals at time t1 and the voltage values ​​of the I and Q signals at time t2, and then calculates the subtraction result P again from the voltage values ​​of the I and Q signals at time t2 and the voltage values ​​of the I and Q signals at time t3. The number of times that the arithmetic processing unit 162 performs the subtraction process is arbitrary, as long as it is two or more.

[0065] Each time the subtraction result P is sent from the calculation processing unit 162, the determination unit 263 determines whether the target is approaching or leaving the radio wave sensor 10. Specifically, the determination unit 263 determines whether the absolute value of the subtraction result P exceeds a predetermined threshold. The predetermined threshold may be stored in a memory provided in the signal processing circuit 26. For example, the predetermined threshold may be set to about twice the expected noise.

[0066] The counter 263A counts the number of times that the absolute value of the subtraction result P exceeds a predetermined threshold for each sign of the subtraction result P (counting process). When the count for each sign of the subtraction result P by the counter 263A exceeds a predetermined number of times, the determination unit 263 determines that the object is approaching or moving away depending on the sign. The predetermined number of times may be stored in a memory provided in the signal processing circuit 26.

[0067] This makes it possible to appropriately determine whether an object is approaching or leaving the radio wave sensor 10 while taking into consideration the presence of noise.

[0068] (Third embodiment) Next, a signal processing circuit 36 ​​according to a third embodiment of the present disclosure and its processing will be described with reference to Fig. 10. Fig. 10 is a diagram illustrating the configuration of the signal processing circuit 36 ​​according to the third embodiment. The signal processing circuit 36 ​​performs addition processing.

[0069] The signal processing circuit 36 ​​includes a signal removal unit 161 similar to the signal processing circuit 16 according to the first embodiment. The signal processing circuit 36 ​​also includes an arithmetic processing unit 362 instead of the arithmetic processing unit 162, and a determination unit 363 instead of the determination unit 163.

[0070] in particular, The calculation processing unit 162 adds the product of the voltage value A of the I signal at time t1 and the voltage value D of the Q signal at time t2 to the product of the voltage value B of the Q signal at time t1 and the voltage value C of the I signal at time t2, If the result of the addition is greater than the result of the subtraction, the determination unit 163 does not determine that an object exists.

[0071] The calculation processing unit 362 adds the product of the voltage value A of the I signal at time t1 and the voltage value D of the Q signal at time t2 to the product of the voltage value B of the Q signal at time t1 and the voltage value C of the I signal at time t2 (addition process), and outputs the addition result S (= AD + BC) to the judgment unit 363.

[0072] The determination unit 363 compares the absolute value of the subtraction result P calculated from the voltage values ​​of the I and Q signals at times t1 and t2 with the absolute value of the addition result S. If the absolute value of the addition result S is greater than the absolute value of the subtraction result P, the determination unit 363 does not determine that an object is present. That is, in this case, the determination unit 363 determines that an object is not present.

[0073] According to this, by combining the results of the calculation processes, it is possible to appropriately determine whether an object is approaching or leaving the radio wave sensor 10.

[0074] (Fourth embodiment) Next, a signal processing circuit 46 according to a fourth embodiment of the present disclosure and its processing will be described with reference to Fig. 11. Fig. 11 is a diagram illustrating the configuration of the signal processing circuit 46 according to the fourth embodiment. The signal processing circuit 46 performs spike removal processing.

[0075] The signal processing circuit 46 includes a signal removal unit 161, an arithmetic processing unit 162, and a determination unit 163, similar to the signal processing circuit according to the first embodiment. Furthermore, the signal processing circuit 46 includes a spike determination and removal unit 465 after the signal removal unit 161. The spike determination and removal unit 465 functions as a "spike removal unit."

[0076] in particular, The device further includes a spike determination and removal unit 465 that replaces voltage values ​​exceeding a predetermined threshold with 0 when the voltage value A of the I signal at time t1, the voltage value B of the Q signal at time t1, the voltage value C of the I signal at time t2, and the voltage value D of the Q signal at time t2 each exceed a predetermined threshold.

[0077] The spike determination and removal unit 465 determines whether or not the voltage value A of the I signal at time t1, the voltage value B of the Q signal at time t1, the voltage value C of the I signal at time t2, and the voltage value D of the Q signal at time t2 exceed a predetermined threshold, and replaces any value that exceeds the predetermined threshold with 0 (spike removal process). In this case, the predetermined threshold may be set as a different threshold for each of A, B, C, and D, or may be set as a common threshold.

[0078] Thereafter, the calculation processing unit 162 calculates the subtraction result P based on A, B, C, and D that have passed the spike removal process, and sends it to the determination unit 163. The determination unit 163 determines whether the object is approaching or leaving the radio wave sensor 10 based on the subtraction result P.

[0079] According to this spike determination and removal, spikes remaining after the large signal removal by the signal removal unit 161 are effectively removed, and it is possible to appropriately determine whether an object is approaching or leaving the radio wave sensor 10.

[0080] (Other Examples) The configurations of the first to fourth embodiments described above can be combined as appropriate.

[0081] The device of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. The program of the present disclosure is a program for causing a computer to realize each function of the device according to the present disclosure, and a program for causing a computer to execute each procedure of the method executed by the device according to the present disclosure. [Explanation of symbols]

[0082] 10, 20: Radio wave sensor 11: Transmitting antenna 12: Receiving antenna 13: Oscillator 14: Phase detector 15, 15A, 15B: AD converter 16, 26, 36: Signal processing circuit 161A, 161B: Signal removal section 162, 362: Processing unit 163, 263, 363: Judgment section 263A: Counter 465: Spike detection and removal section 17A, 17B: High-pass filter 18A, 18B: Amplifier 100: Microwave Doppler detector 101: Doppler sensor circuit section

Claims

1. an antenna that transmits radio waves and receives the radio waves reflected by an object; a phase detection circuit that outputs a first signal and a second signal that is out of phase with the first signal by 90 degrees based on a signal from the antenna; a calculation processing unit that acquires a plurality of voltage values ​​of the first signal and a plurality of voltage values ​​of the second signal from the phase detection circuit at predetermined time intervals and performs calculation processing based on the acquired plurality of voltage values; a determination unit that determines movement of an object based on a result of the arithmetic processing by the arithmetic processing unit; Equipped with Radio wave sensor.

2. the calculation processing unit subtracts a product of a voltage value of the second signal at a first time point and a voltage value of the first signal at a second time point different from a product of a voltage value of the first signal at the first time point and a voltage value of the second signal at the second time point different from the first time point; the determination unit determines the moving direction of the object based on the result of the subtraction performed by the calculation processing unit. The radio wave sensor according to claim 1 .

3. the calculation processing unit executes the subtraction a plurality of times, the determination unit determines the moving direction of the object based on the results of the subtraction performed multiple times by the calculation processing unit. The radio wave sensor according to claim 2.

4. The determination unit determines that the object is moving in a direction approaching or moving away from the antenna when the number of times the result of the subtraction exceeds a predetermined threshold exceeds a predetermined number. The radio wave sensor according to claim 3.

5. the calculation processing unit adds a product of a voltage value of the first signal at the first time point and a voltage value of the second signal at the second time point and a product of a voltage value of the second signal at the first time point and a voltage value of the first signal at the second time point; the determination unit does not determine that an object is present when the result of the addition is greater than the result of the subtraction. The radio wave sensor according to claim 2.

6. a spike removal unit that, when a voltage value of the first signal at the first time point, a voltage value of the second signal at the first time point, a voltage value of the first signal at the second time point, and a voltage value of the second signal at the second time point each exceed a predetermined threshold, replaces the voltage value that exceeds the predetermined threshold with 0. The radio wave sensor according to claim 2.

7. the first signal and the second signal are Doppler IQ signals; The radio wave sensor according to any one of claims 1 to 6.

Images