A method for calibrating the transmission channel of active array ground wave radar

Abstract

The invention discloses a method for calibrating a transmitting channel of an active array ground wave radar. N The waveguide port of each array element couples and samples the transmitted signal, sends the sampled signal to the receiver for processing, and then uploads the IQ signal to the terminal software. The terminal software receives the IQ signal until it covers a working cycle of the ground wave radar. The IQ data within a working cycle are respectively calculated by inverse tangent to obtain N The phase value related to the transmission signal is obtained by grouping; taking any array element in the array as the benchmark, the phase values ​​of the remaining array elements are respectively matched with the phase value of the benchmark array element, and the difference is summed to obtain the average value. After accumulating multiple ground wave radar working cycles, the average value is taken as the phase deviation value between the remaining array elements and the benchmark array element; the terminal software generates the phase control word of each array element signal according to the phase deviation value between the benchmark array element and the remaining array elements and sends it to the transmission signal generation module, thereby completing the array transmission channel calibration.

Description

Technical Field

[0001] The invention belongs to the technical field of ground wave radar, and in particular relates to a method for calibrating a transmitting channel of an active array ground wave radar. Background Art

[0002] my country has a vast ocean with a coastline stretching for thousands of kilometers. Marine environmental monitoring and detection of distant low-altitude targets are of great significance to my country's economic development and national defense security. The operating frequency band of high-frequency ground wave radar is 3 to 30 MHZ. The vertically polarized electromagnetic waves it emits are diffracted along the coastal plane, with low propagation attenuation and unaffected by the curvature of the earth. It can achieve over-the-horizon detection of targets and long-distance marine environmental monitoring. For ground wave radars with active phased array systems, the consistency of the array transmission channel directly affects the accuracy of the transmission synthetic beam pointing; the traditional transmission channel calibration method is that all array elements in the array transmit signals at the same time, and the signals are connected to the logic analyzer at the waveguide port of each array element after passing through the attenuator, thereby determining the phase relationship of the signals transmitted by each array element, and storing these phase relationships offline in the radar. Although the traditional array channel calibration method can complete the transmission channel calibration of active array ground wave radars, it still has the following shortcomings:

[0003] 1. Depends on equipment such as logic analyzers and attenuators;

[0004] 2. Building a calibration platform is relatively complicated, and the complexity increases with the number of array elements;

[0005] 3. It is impossible to perform array transmission channel calibration online in real time;

[0006] 4. It is only applicable to on-site calibration. Once the ground wave radar is set up on site, this method is difficult to implement. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide an active array ground wave radar transmission channel calibration method in view of the shortcomings of the background technology, which can complete the active array ground wave radar transmission channel calibration more conveniently, eliminate the dependence on test equipment, and can perform array transmission channel calibration online in real time, thus solving the problem that array channel calibration is difficult to implement after the ground wave radar is set up on site.

[0008] The present invention adopts the following technical solutions to solve the above technical problems:

[0009] A method for calibrating an active array ground wave radar transmission channel comprises the following steps:

[0010] Step 1: Set the same working parameters for N array elements in the array and make them work in the transmitting state, and sample the transmitting signals through the receiver at the waveguide ports of the N array elements;

[0011] Step 2: The receivers of the N array elements respectively perform ADC, orthogonal, filtering, extraction and other processing on the sampled signals of the array elements in step 1, and then upload the IQ signals to the terminal software;

[0012] Step 3: The terminal software receives the IQ signals uploaded by N array element receivers in the array until one working cycle of the ground wave radar is covered; the data DATA received by each array element N As shown in the following formula, N represents the array element number, and k represents the number of IQ data uploaded by each array element in one working cycle:

[0013]

[0014] Step 4, calculating the phase values ​​of N array elements related to the transmitted signal within a ground wave radar working cycle;

[0015] Step 5, finding the average phase deviation of the N array element transmission signals within a ground wave radar working cycle;

[0016] Step 6, accumulating multiple ground wave radar working cycles, that is, performing the above steps 1-5 multiple times, and averaging the phase deviation average value in step 5 to calculate the phase deviation average value of the N array element transmission signals in multiple ground wave radar working cycles;

[0017] Step 7: Using the average phase deviation of the N array elements obtained in step 6 as the phase compensation value of the N array element transmit signals, thereby completing the calibration of the active array ground wave radar transmit channel.

[0018] Furthermore, in step 4, the calculation method is to perform arc tangent operation on the IQ data of N array elements within one working cycle to obtain N groups of phase values ​​θ related to the transmitted signal. N , as shown below, where N represents the array element number and k represents the number of IQ data uploaded by each array element in a working cycle:

[0019]

[0020]

[0021] Furthermore, in step 5, the calculation method is to take any array element as the reference, and the phase value θ of the reference array element base As shown in the following formula, base is the number of the base array element, and k represents the number of IQ data uploaded by each array element in a working cycle:

[0022]

[0023] Then the phase values ​​θ of the remaining array elements are M The phase value θ of the reference array element is baseThe phase difference between the remaining array elements and the reference array element is obtained by one-to-one difference. M , as shown below, where M represents the numbers of the remaining array elements except the reference array element:

[0024]

[0025]

[0026] Then the phase difference δ between the remaining array elements and the reference array element is calculated. M Calculate the average value β within a ground wave radar working cycle M , as shown below, where M represents the numbers of the remaining array elements except the reference array element;

[0027]

[0028] Furthermore, in step 6, the average phase deviation η between the remaining array elements and the reference array element transmitting signals in multiple ground wave radar working cycles is calculated. M , as shown below, where p represents the number of accumulated working cycles and M represents the numbers of the remaining array elements except the reference array element:

[0029]

[0030] Furthermore, in step 7, the average phase deviation of the N array elements obtained in step 6 is used as the phase compensation value of the N array element transmit signals. The implementation method is that the terminal software generates a phase control word for each array element signal according to the phase deviation value between the reference array element and the remaining array elements and sends it to the transmit signal generation module. Each array element transmit signal generation module adjusts the phase of the transmit signal according to the received phase control word, thereby completing the calibration of the active array ground wave radar transmit channel.

[0031] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0032] The array calibration method adopted by the present invention can be completed in the active array ground wave radar, and does not need to build an additional test platform, thereby improving the convenience of work implementation and getting rid of the dependence on test equipment such as logic analyzers and attenuators; more importantly, the difficulty of array transmission channel calibration work after the active array ground wave radar is set up on site is greatly reduced, and online real-time array transmission channel calibration can be performed, thereby improving the adaptability of the active array ground wave radar to the on-site environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of the implementation method of this embodiment. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0035] In the description of the present invention, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second" and the like do not indicate the importance of the components, and therefore cannot be understood as limiting the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution, and do not limit the scope of protection of the present invention.

[0036] The present invention provides a method for calibrating an active array ground wave radar transmission channel, which is characterized by comprising the following steps:

[0037] Step 1: Set the same working parameters for N array elements in the array and make them work in the transmitting state, and sample the transmitting signals through the receiver at the waveguide ports of the N array elements;

[0038] Step 2: The receivers of the N array elements respectively perform ADC, orthogonal, filtering, extraction and other processing on the sampled signals of the array elements in step 1, and then upload the IQ signals to the terminal software;

[0039] Step 3: The terminal software receives the IQ signals uploaded by N array element receivers in the array until one working cycle of the ground wave radar is covered; the data DATA received by each array element N As shown in the following formula, N represents the array element number, and k represents the number of IQ data uploaded by each array element in one working cycle:

[0040]

[0041] Step 4, calculating the phase values ​​of N array elements related to the transmitted signal within a ground wave radar working cycle;

[0042] The calculation method is to perform arc tangent operation on the IQ data of N array elements in one working cycle to obtain N groups of phase values ​​θ related to the transmitted signal. N , as shown below, where N represents the array element number and k represents the number of IQ data uploaded by each array element in a working cycle:

[0043]

[0044]

[0045] Step 5, finding the average phase deviation of the N array element transmission signals within a ground wave radar working cycle;

[0046] The calculation method is to take any array element as the reference, and the phase value θ of the reference array elementbase As shown in the following formula, base is the number of the base array element, and k represents the number of IQ data uploaded by each array element in a working cycle:

[0047]

[0048] Then the phase values ​​θ of the remaining array elements are M The phase value θ of the reference array element is base The phase difference between the remaining array elements and the reference array element is obtained by one-to-one difference. M , as shown below, where M represents the numbers of the remaining array elements except the reference array element:

[0049]

[0050]

[0051] Then the phase difference δ between the remaining array elements and the reference array element is calculated. M Calculate the average value β within a ground wave radar working cycle M , as shown below, where M represents the numbers of the remaining array elements except the reference array element;

[0052]

[0053] Step 6, accumulating multiple ground wave radar working cycles, that is, performing the above steps 1-5 multiple times, and averaging the phase deviation average value in step 5 to calculate the phase deviation average value of the N array element transmission signals in multiple ground wave radar working cycles;

[0054] Calculate the average phase deviation η of the transmitted signals of the remaining array elements and the reference array element during multiple ground wave radar working cycles M , as shown below, where p represents the number of accumulated working cycles and M represents the numbers of the remaining array elements except the reference array element:

[0055]

[0056] Step 7, using the average value of the phase deviations of the N array elements obtained in step 6 as the phase compensation value of the N array element transmit signals, thereby completing the calibration of the active array ground wave radar transmit channel;

[0057] The average phase deviation of the N array elements obtained in step 6 is used as the phase compensation value of the N array element transmit signals. The implementation method is that the terminal software generates a phase control word for each array element signal according to the phase deviation value between the reference array element and the remaining array elements and sends it to the transmit signal generation module. Each array element transmit signal generation module adjusts the phase of the transmit signal according to the received phase control word, thereby completing the calibration of the active array ground wave radar transmit channel.

[0058] The specific embodiments are as follows:

[0059] The present invention is described in detail by taking an active array ground wave radar including eight array elements as an example. Figure 1 As shown, the specific steps include:

[0060] Step 1, set the working parameters of the eight array elements of the active array ground wave radar as follows: working cycle is 652.8ms, pulse period is 3.2ms, pulse width is 1.58ms, number of pulses is 192, transmission signal frequency is 8.500003MHz and initial phase is 0; control the eight array elements to be in the transmitting state, and couple and sample the transmission signals at the waveguide ports of the eight array elements.

[0061] Step 2: The receivers of the eight array elements perform ADC, orthogonalization, filtering, and extraction on the transmitted sampling signals of the array elements in step 1 respectively. The ADC rate is 50MSPS, the orthogonal local oscillator signal frequency is 8.5MHz, and the extraction rate is 15000. The processed IQ signals are uploaded to the terminal software through the network port.

[0062] Step 3: The terminal software needs to receive the IQ signals uploaded by eight array elements for one working cycle. In this example, the working cycle is 652.8 ms, and the array element IQ signal upload data rate is 3333 Hz. Therefore, the number of points that the terminal software needs to receive the IQ signal uploaded by each array element in one working cycle is 2176.

[0063] Step 4: Perform an arctangent operation on the eight groups of IQ signals with a length of 2176 corresponding to the eight array elements received in step 3 to obtain eight groups of phase values ​​with a length of 2176 corresponding to the eight array elements.

[0064] Step 5: Taking any array element as a reference, that is, taking any phase value of the eight groups of phase values ​​with a length of 2176 corresponding to the eight array elements in step 4 as a reference, the seven groups of phase values ​​corresponding to the remaining seven array elements are respectively subtracted from the one group of phase values ​​of the reference array element in a one-to-one correspondence to obtain seven groups of phase difference values ​​with a length of 2176 corresponding to the phase relationship between the remaining seven array elements and the reference array element; and summing and averaging the seven groups of phase difference values ​​with a length of 2176 to obtain the average phase deviation between the remaining seven array elements and the reference array element within one working cycle.

[0065] Step 6: Accumulate 10 working cycles to obtain the average phase deviations between the remaining seven array elements and the reference array element within 10 working cycles obtained in step 5; average the average phase deviations between each array element and the reference array element within 10 working cycles to obtain the average phase deviations between the remaining seven array elements and the reference array element within 10 working cycles.

[0066] Step 7: Taking the average phase deviation between the remaining seven array elements and the reference array element obtained in step 6, and the initial phase of the reference array element transmitting signal as 0, the terminal software converts the first 8 phase values ​​into a phase control word recognizable by the array element transmitting signal generation module and sends it to each array element through the network port. The array element completes the adjustment of the transmitting signal according to the phase control word, thereby completing the calibration of the active array ground wave radar transmitting channel.

[0067] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0068] The above embodiments are only for explaining the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the present invention. The above embodiments of the present invention are described in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present invention.

Claims

1. A method for calibrating an active array ground wave radar transmission channel, characterized in that: The following steps are involved: Step 1: Set the same working parameters for N array elements in the array and make them work in the transmitting state, and sample the transmitting signals through the receiver at the waveguide ports of the N array elements; Step 2: The receivers of the N array elements respectively perform ADC, orthogonalization, filtering, and extraction on the sampled signals of the array elements in step 1, and then upload the IQ signals to the terminal software; Step 3: The terminal software receives the IQ signals uploaded by N array element receivers in the array until one working cycle of the ground wave radar is covered; the data DATA received by each array element N As shown in the following formula, N represents the array element number, and k represents the number of IQ data uploaded by each array element in one working cycle: The working cycle is 652.8ms, and the data rate of each array element IQ signal upload is 3333Hz. The number of points that the terminal software needs to receive the IQ signal uploaded by each array element in one working cycle will be 2176; Step 4, calculating the phase values ​​of N array elements related to the transmitted signal within a ground wave radar working cycle; Step 5, finding the average phase deviation of the N array element transmission signals within a ground wave radar working cycle; Step 6, accumulating multiple ground wave radar working cycles, that is, performing the above steps 1 to 5 multiple times, and averaging the phase deviation average value in step 5 to calculate the phase deviation average value of the N array element transmission signals in multiple ground wave radar working cycles; Step 7: Using the average phase deviation of the N array elements obtained in step 6 as the phase compensation value of the N array element transmit signals, thereby completing the calibration of the active array ground wave radar transmit channel.

2. The method for calibrating the transmitting channel of an active array ground wave radar according to claim 1, characterized in that: In step 4, the calculation method is to perform arc tangent operation on the IQ data of N array elements in one working cycle to obtain N groups of phase values ​​θ related to the transmitted signal. N , the specific expression is: Wherein, N represents the array element number, and k represents the number of IQ data uploaded by each array element in one working cycle.

3. The method for calibrating the transmitting channel of an active array ground wave radar according to claim 1, characterized in that: In step 5, the calculation method is to take any array element as the reference, and the phase value θ of the reference array element base The expression is: Wherein, base is the number of the base array element, k represents the number of IQ data uploaded by each array element in one working cycle; Then the phase values ​​θ of the remaining array elements are M The phase value θ of the reference array element is base The phase difference between the remaining array elements and the reference array element is obtained by one-to-one difference. M , as shown in the following formula, where M represents the numbers of the remaining array elements except the reference array element; Then the phase difference δ between the remaining array elements and the reference array element is calculated. M Calculate the average value β within a ground wave radar working cycle M , the specific expression is: Wherein, M represents the numbers of the remaining array elements except the reference array element.

4. The method for calibrating the transmitting channel of an active array ground wave radar according to claim 1, characterized in that: In step 6, the average phase deviation η of the signal transmitted by the remaining array elements and the reference array element in multiple ground wave radar working cycles is calculated. M , as shown in the following formula, where p represents the number of accumulated working cycles and M represents the numbers of the remaining array elements except the reference array element:

5. The method for calibrating the transmitting channel of an active array ground wave radar as claimed in claim 1, characterized in that: In step 7, the average phase deviation of the N array elements obtained in step 6 is used as the phase compensation value of the N array element transmit signals. The implementation method is that the terminal software generates a phase control word for each array element signal according to the phase deviation value between the reference array element and the remaining array elements and sends it to the transmit signal generation module. Each array element transmit signal generation module adjusts the phase of the transmit signal according to the received phase control word, thereby completing the calibration of the active array ground wave radar transmit channel.

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