A target detection method, system and device based on phased array non-blind zone transmission

Abstract

The present invention relates to the technical field of phased array radar, and in particular to a target detection method, system and device based on phased array non-blind zone transmission, the steps are as follows: the radar repeatedly executes the first to third transmission modes to obtain a first echo signal corresponding to the first transmission mode, a second echo signal corresponding to the second transmission mode and a third echo signal corresponding to the third transmission mode; based on the first echo signal, the second echo signal and the third echo signal, target detection is performed to determine short-range target information and long-range target information. In the first and second transmission modes, the present invention uses a single array element to transmit a narrow pulse. Since the transmission power is low and the transmitting array element is far away from the receiving array element that receives in rotation, the isolation between the transmitting and receiving array elements is high, so short-range target detection is performed, and the short-range blind zone can theoretically reach 0 meters; in the third mode, the array elements are used to simultaneously transmit wide pulses, and the transmission power is high, which can be used for long-range target detection.

Description

Technical Field

[0001] The present invention relates to the technical field of phased array radars, and in particular to a target detection method, system and device based on phased array blind-area-free transmission. Background Art

[0002] Due to the obstruction of the transmitted pulse signal, the phased array radar cannot receive the echo of close-range targets, resulting in the inability to detect close-range targets. This is the close-range blind spot problem of the phased array radar.

[0003] There are many methods for phased array radar blind spot filling. The most commonly used method is the wide and narrow pulse blind spot filling method, that is, wide and narrow pulses are emitted alternately by frame or pulse. Wide pulses are used for long-distance target detection, but there is a close-range blind spot. Narrow pulses are used for close-range target detection to complete the blind spot filling of wide pulse close-range blind spots. However, at the current hardware level, the minimum narrow pulse is about 1us, and after adding the non-ideality of the radar transceiver switching component, assuming that the radar emits a narrow pulse for 1.3us, the minimum radar detection blind spot is about 200 meters. For some special applications, such as micro-UAV detection radar, the blind spot is too large. Summary of the invention

[0004] The purpose of the present invention is to provide a target detection method, system and device based on phased array blind-spot-free transmission. By switching the transmission and reception of the phased array radar, the transmission mode of the phased array radar is optimized and improved, and long-distance detection can be achieved while detecting short-range blind spots, so as to solve the technical problem of poor blind spot filling effect of the existing wide and narrow pulse blind spot filling method.

[0005] The present invention is implemented by the following technical scheme: based on the target detection method of phased array non-blind zone transmission, the antenna of the phased array radar is divided into a first antenna array and a second antenna array, and a first transmission mode, a second transmission mode and a third transmission mode are configured, wherein in the first transmission mode, any array element in the first antenna array transmits a narrow pulse in each pulse repetition period, and the array elements in the second antenna array receive echoes in rotation in each pulse repetition period until all array elements complete one reception, in the second transmission mode, any array element in the second antenna array transmits a narrow pulse in each pulse repetition period, and the array elements in the first antenna array receive echoes in rotation in each pulse repetition period until all array elements complete one reception, in the third transmission mode, all array elements in the first antenna array and the second antenna array transmit a wide pulse at the same time, and after the wide pulse transmission is completed, all array elements in the first antenna array and the second antenna array are switched to a receiving state to receive echoes, and the method comprises the following steps:

[0006] The radar repeatedly executes the first to third transmission modes to obtain a first echo signal corresponding to the first transmission mode, a second echo signal corresponding to the second transmission mode, and a third echo signal corresponding to the third transmission mode;

[0007] Target detection is performed based on the first echo signal, the second echo signal, and the third echo signal to determine short-range target information and long-range target information.

[0008] According to a preferred embodiment, before performing target detection based on the first echo signal, the second echo signal and the third echo signal, the method further includes:

[0009] The sum signal of the first echo signal and the second echo signal are pulse compressed to obtain a first range-dimensional echo signal, and the sum signal and the difference signal in the third echo signal are pulse compressed to obtain a second range-dimensional echo signal.

[0010] According to a preferred embodiment, the close-range target information is acquired in the following manner:

[0011] Performing coherent processing on the signals obtained by the same transmitting and receiving array elements in the first range-dimensional echo signal, and performing fast Fourier transform on the coherent processing result to obtain a first range Doppler matrix;

[0012] Performing incoherent processing on all first range Doppler matrices, and detecting the incoherent processing results using the CFAR algorithm to obtain the first target range Doppler information;

[0013] The target Doppler frequency is calculated and combined with the maximum time delay of the echo signal received by the narrow pulse to obtain different phase compensation factors;

[0014] Based on the phase compensation factor, phase compensation is performed on the first target range Doppler information according to the receiving timing to obtain a target echo compensation signal;

[0015] According to the position information of the transmitting array elements in the first antenna array and the second antenna array and the position information of the receiving array elements in the first antenna array and the second antenna array, the preset target angle is used Construct different steering vectors, obtain the amplitude by taking the inner product of the different steering vectors and the target echo compensation signal, and output the corresponding Determine close range target information.

[0016] According to a preferred embodiment, the expression of the phase compensation factor is: , ,in, , is the Doppler frequency, , is the wavelength of the transmitted radar signal, is the relative position between the transmitting array element and the target, is the maximum time delay of the echo signal received by the narrow pulse, is the number of elements of the first antenna array, is the number of elements of the second antenna array.

[0017] According to a preferred embodiment, the steering vector is expressed as follows:

[0018]

[0019] In the above formula, A is the steering vector, is the spacing between the transmitting elements in the first antenna array and the second antenna array, The first antenna array The coordinates of the receiving array elements, For the second line array The coordinates of the receiving array elements.

[0020] According to a preferred embodiment, the long-distance target information is obtained as follows:

[0021] Performing coherent processing on the second range dimension echo signal, and performing fast Fourier transform on the coherent processing result to obtain a second range Doppler matrix;

[0022] Performing incoherent processing on the second range Doppler matrix, and detecting the incoherent processing result by using the CFAR algorithm to obtain the second target range Doppler information;

[0023] The second target range Doppler information obtained under the sum signal and the second target range Doppler information obtained under the difference signal are used to perform sum and difference angle measurement to determine the long-distance target information.

[0024] The present invention also provides a target detection system based on phased array transmission without blind spots, which is applied to the method described above.

[0025] According to a preferred embodiment, the system includes a signal processing board, an intermediate frequency signal module, an up-conversion module, a power divider, a plurality of transceiver switching components, a summator, a sum-path down-conversion module and a difference-path down-conversion module;

[0026] Among them, the signal output end of the intermediate frequency signal module is connected to the signal input end of the up-conversion module, the signal output end of the up-conversion module is connected to the signal input end of the power divider, the signal output end of the power divider is connected to the signal input end of each transceiver switching component, each of the transceiver switching components corresponds to the array elements in the first antenna array and the second antenna array one by one and is bidirectionally connected, the signal output end of the transceiver switching component is connected to the signal input end of the summator, the signal output end of the summator is connected to the signal input end of the signal processing board via the summing path down-conversion module and the differential path down-conversion module, and the signal processing board is bidirectionally connected to the intermediate frequency signal module.

[0027] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described above when executing the computer program.

[0028] The technical solutions of a target detection method, system and device based on phased array transmission without blind spots provided by the present invention have at least the following advantages and beneficial effects: (1) In the first transmission mode and the second transmission mode, a single array element is used to transmit a narrow pulse. Since the transmission power is low and the transmitting array element is far away from the receiving array element that receives in rotation, the isolation between the transmitting and receiving array elements is high. Therefore, when the simultaneous transmission and reception mode is used for close-range target detection, the minimum target detection distance, that is, the close-range blind spot can theoretically reach 0 meters; (2) In the third mode, the array elements are used to simultaneously transmit wide pulses, and the transmission power is high, which can be used for long-range target detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic flow chart of a target detection method based on phased array transmission without blind spots provided in Embodiment 1 of the present invention;

[0030] Figure 2 A schematic diagram of receiving and transmitting signals for executing first to third transmission modes provided in Embodiment 1 of the present invention;

[0031] Figure 3 The phased array radar hardware architecture of the target detection system based on phased array non-blind-spot transmission provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Example 1

[0034] Figure 1 A flow chart of a target detection method based on phased array transmission without blind spots provided in Example 1 of the present invention. In one implementation of this embodiment, the specific implementation of phased array transmission without blind spots is as follows:

[0035] The antenna of the phased array radar is divided into the first antenna array and the second antenna array, such as Figure 2 As shown, TX1~TX4 are the first antenna array, and TX5~TX8 are the second antenna array.

[0036] Further, a first transmission mode, a second transmission mode and a third transmission mode are configured.

[0037] In the first transmission mode, any array element in the first antenna array, such as TX1, transmits a narrow pulse in each pulse repetition period, and the pulse repetition period is set to , that is, every time After a period of time, TX1 transmits a narrow pulse; the array elements in the second antenna array receive the echo in turn in each pulse repetition period until all array elements complete a reception. In one implementation of this embodiment, TX1 first transmits a pulse with a width of At the same time, TX5 switches to the receiving state to receive the echo of TX1 and obtains the echo signal RX5. After a certain time, TX1 transmits a pulse with a width of At the same time, TX6 switches to the receiving state to receive the echo of TX1 and obtains the echo signal RX6. After a certain time, TX1 transmits again until TX8 completes the reception and obtains the echo signal RX8.

[0038] In the second transmission mode, any array element in the second antenna array, such as TX8, transmits a narrow pulse in each pulse repetition period. The pulse repetition period is set to , that is, every time time, TX8 transmits a narrow pulse; the array elements in the first antenna array receive the echo in turn in each pulse repetition period until all array elements complete one reception; in one implementation of this embodiment, in the first transmission mode, after TX8 completes the reception, TX8 is switched to the transmission state, and TX8 transmits a pulse with a width of At the same time, TX1 switches to the receiving state to receive the echo of TX8 and obtains the echo signal RX1. After a certain time, TX8 transmits a pulse with a width of At the same time, TX2 switches to the receiving state to receive the echo of TX8 and obtains the echo signal RX2. After a certain time, TX8 transmits again until TX4 completes the reception and obtains the echo signal RX4.

[0039] It should be noted that in the first transmission mode and the second transmission mode, a single array element is used to transmit a narrow pulse. Since the transmission power is low and the transmitting array element is far away from the receiving array element that receives in rotation, the isolation between the transmitting and receiving array elements is high. Therefore, when the simultaneous transmission and reception mode is used for close-range target detection, the minimum target detection distance, that is, the close-range blind area can theoretically reach 0 meters.

[0040] In the third transmission mode, all array elements TX1 to TX8 in the first antenna array and the second antenna array simultaneously transmit a pulse with a width of The wide pulse > After the wide pulse transmission is completed, all array elements TX1~TX8 in the first antenna array and the second antenna array are switched to the receiving state to receive the echo, and the echo signals RX1~RX8 are obtained. The receiving delay of the echo is .

[0041] It should be noted that in the third mode, the array elements simultaneously transmit wide pulses, and the radar transmit power is , compared to the transmission power of a single antenna Increased times, so it can be used for long-distance target detection.

[0042] See also Figure 1 As shown, the target detection method based on phased array transmission without blind spots in this embodiment includes the following steps:

[0043] First, the radar repeatedly executes the above-mentioned first to third transmission modes Q times to obtain the first echo signals RX5~RX8 corresponding to the first transmission mode, the second echo signals RX1~RX4 corresponding to the second transmission mode, and the third echo signals RX1~RX8 corresponding to the third transmission mode.

[0044] Perform pulse compression processing on the sum signal of the first echo signal RX5~RX8 to obtain the first distance dimension echo signal , , and ; Perform pulse compression processing on the sum signal of the second echo signal to obtain the first distance dimension echo signal , , and ; Perform pulse compression processing on the sum path signal and the difference path signal of the third echo signal respectively to obtain the second distance dimension echo signal of the sum path The second distance dimension echo signal of the sum and difference path ,

[0045] Furthermore, target detection is performed based on the first echo signal, the second echo signal, and the third echo signal after the pulse compression processing to determine short-range target information and long-range target information.

[0046] Specifically in one implementation of this embodiment, in target detection, the steps for acquiring close-range target information are as follows:

[0047] The Q repetitive pulse groups are accumulated, that is, the signals obtained by the same transmitting and receiving array elements in the first range dimension echo signal are coherently processed, and the signals obtained by the same transmitting and receiving array elements are taken as a group, which can be expressed as , is the distance dimension vector.

[0048] Perform fast Fourier transform (FFT) on all coherent processing results to obtain The first range Doppler matrix under the same transmitting and receiving array elements can be expressed as , , , ,in The first range Doppler matrix corresponding to TX1 transmission and TX5 reception, The first range Doppler matrix corresponding to TX1 transmission and TX6 reception, The first range Doppler matrix corresponding to TX8 transmission and TX1 reception, and so on.

[0049] For all first range Doppler matrices , , , Perform incoherent processing, that is .

[0050] The range Doppler matrix obtained by incoherent processing The CFAR algorithm is used for detection to obtain the first target range Doppler information, which can be expressed as .

[0051] Calculate the target Doppler frequency, , is the wavelength of the transmitted radar signal, is the relative position of the transmitting array element and the target; combined with the maximum time delay of the echo signal received by the narrow pulse Different phase compensation factors are calculated , ,in, , is the number of elements of the first antenna array, is the number of elements of the second antenna array. In this embodiment, , , is 4.

[0052] Based on the phase compensation factor , according to the receiving timing, the first target range Doppler information Phase compensation is performed to obtain a target echo compensation signal; in this embodiment, the receiving timing is RX5, RX6, RX7, RX8, RX1, RX2, RX3, RX4, so the target echo compensation signal obtained is It can be expressed as follows:

[0053]

[0054] According to the position information of the transmitting array elements in the first antenna array and the second antenna array and the position information of the receiving array elements in the first antenna array and the second antenna array, the preset target angle is used Construct different steering vectors, calculate the inner product of different steering vectors and target echo compensation signals to obtain the amplitude, and output the corresponding Determine close-range target information, including: Can be set to .

[0055] In one implementation of this embodiment, the steering vector is expressed as follows:

[0056]

[0057] In the above formula, A is the steering vector, is the spacing between the transmitting elements in the first antenna array and the second antenna array, The first antenna array The coordinates of the receiving array elements, For the second line array The coordinates of the receiving array elements.

[0058] Specifically in one implementation of this embodiment, in target detection, the steps of acquiring long-distance target information are as follows:

[0059] The second range dimension echo signal is coherently processed, and the coherent processing result is processed by fast Fourier transform FFT to obtain the second range Doppler matrix of the difference path where the transmitting array element transmits simultaneously and the receiving array element receives simultaneously , the second range Doppler matrix of the sum of the paths where the transmitting array elements transmit simultaneously and the receiving array elements receive simultaneously .

[0060] For the second range Doppler matrix , Incoherent processing is performed, and the incoherent processing result is detected using a CFAR algorithm to obtain the second target range Doppler information obtained under the sum signal and the second target range Doppler information obtained under the difference signal.

[0061] Furthermore, the second target range Doppler information obtained under the sum path signal and the second target range Doppler information obtained under the difference path signal are used to perform sum and difference angle measurement to determine the long-distance target information.

[0062] Example 2

[0063] This embodiment provides a target detection system based on phased array transmission without blind spots based on the technical solution provided in Embodiment 1. The system is applied to the method in Embodiment 1.

[0064] Specifically in this embodiment, see Figures 2 to 3 As shown, the system includes a signal processing board, an intermediate frequency signal module, an up-conversion module, a power divider, a plurality of transceiver switching components, a summator, a sum-path down-conversion module and a difference-path down-conversion module.

[0065] Among them, the signal transmitted by the radar is first generated by the intermediate frequency signal module, the signal output end of the intermediate frequency signal module is connected to the signal input end of the up-conversion module, the signal output end of the up-conversion module is connected to the signal input end of the power divider, and the signal output end of the power divider is connected to the signal input end of each transceiver switching component. The signal generated by the intermediate frequency signal module is converted into a radio frequency signal after passing through the up-conversion module. The radio frequency signal is then divided by the power divider to each transceiver switching component, that is, the input end of the T / R component. Each transceiver switching component corresponds to the array elements in the first antenna array and the second antenna array one by one and is bidirectionally connected. Among them, the power amplifier of each transceiver switching component amplifies the radio frequency signal and switches it to the transmitting port through a switch, and then radiates outward through the corresponding array element.

[0066] The signal output end of the transceiver switching component is connected to the signal input end of the summator. The receiving array element transmits the received echo to the summator through the receiving link of the transceiver switching component for synthesis to obtain a sum signal and a difference signal. The signal output end of the summator is connected to the signal input end of the signal processing board through the summation down-conversion module and the difference down-conversion module. The signal processing board is bidirectionally connected to the intermediate frequency signal module. The summation signal and the difference signal are converted into intermediate frequency signals through the down-conversion module and then sampled by the ADC of the signal processing board. After that, the signal is processed by the signal processing board, thereby obtaining the target echo information.

[0067] Example 3

[0068] Based on the technical solution provided in Example 1, this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method in Example 1 is implemented.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A target detection method based on phased array transmission without blind spots, characterized in that: The antenna of the phased array radar is divided into a first antenna array and a second antenna array, and a first transmission mode, a second transmission mode and a third transmission mode are configured, wherein in the first transmission mode, any array element in the first antenna array transmits a narrow pulse in each pulse repetition period, and the array elements in the second antenna array receive echoes in rotation in each pulse repetition period until all array elements complete one reception, in the second transmission mode, any array element in the second antenna array transmits a narrow pulse in each pulse repetition period, and the array elements in the first antenna array receive echoes in rotation in each pulse repetition period until all array elements complete one reception, in the third transmission mode, all array elements in the first antenna array and the second antenna array transmit a wide pulse at the same time, and after the wide pulse transmission is completed, all array elements in the first antenna array and the second antenna array are switched to a receiving state to receive echoes, and the method comprises the following steps: The radar repeatedly executes the first to third transmission modes to obtain a first echo signal corresponding to the first transmission mode, a second echo signal corresponding to the second transmission mode, and a third echo signal corresponding to the third transmission mode; Target detection is performed based on the first echo signal, the second echo signal, and the third echo signal to determine short-range target information and long-range target information.

2. The target detection method based on phased array non-blind-area transmission according to claim 1, characterized in that: Before performing target detection based on the first echo signal, the second echo signal, and the third echo signal, the method further includes: The sum signal of the first echo signal and the second echo signal are pulse compressed to obtain a first range-dimensional echo signal, and the sum signal and the difference signal in the third echo signal are pulse compressed to obtain a second range-dimensional echo signal.

3. The target detection method based on phased array non-blind-area transmission as claimed in claim 2, characterized in that: The method for obtaining the close-range target information is as follows: Performing coherent processing on the signals obtained by the same transmitting and receiving array elements in the first range-dimensional echo signal, and performing fast Fourier transform on the coherent processing result to obtain a first range Doppler matrix; Performing incoherent processing on all first range Doppler matrices, and detecting the incoherent processing results using the CFAR algorithm to obtain the first target range Doppler information; The target Doppler frequency is calculated and combined with the maximum time delay of the echo signal received by the narrow pulse to obtain different phase compensation factors; Based on the phase compensation factor, phase compensation is performed on the first target range Doppler information according to the receiving timing to obtain a target echo compensation signal; According to the position information of the transmitting array elements in the first antenna array and the second antenna array and the position information of the receiving array elements in the first antenna array and the second antenna array, different steering vectors are constructed using the preset target angle, the amplitude is obtained by calculating the inner product of the different steering vectors and the target echo compensation signal, and the close-range target information is determined based on the maximum amplitude output.

4. The target detection method based on phased array non-blind-area transmission as claimed in claim 3, characterized in that: The expression of the phase compensation factor is: , ,in, , is the Doppler frequency, , is the wavelength of the transmitted radar signal, is the relative position between the transmitting array element and the target, is the maximum time delay of the echo signal received by the narrow pulse, is the number of elements of the first antenna array, is the number of elements of the second antenna array.

5. The target detection method based on phased array non-blind-area transmission as claimed in claim 3, characterized in that: The expression of the steering vector is as follows: In the above formula, A is the steering vector, is the spacing between the transmitting elements in the first antenna array and the second antenna array, The first antenna array The coordinates of the receiving array elements, For the second line array The coordinates of the receiving array elements, is the number of elements of the first antenna array, is the number of elements of the second antenna array, represents the steering vector of the transmitting array elements in the first antenna array and the second antenna array, represents the steering vector of the receiving element in the first antenna array, represents the steering vector of the receiving element in the second antenna array.

6. The target detection method based on phased array non-blind-area transmission according to any one of claims 3 to 5, characterized in that: The long-distance target information acquisition method is as follows: Performing coherent processing on the second range dimension echo signal, and performing fast Fourier transform on the coherent processing result to obtain a second range Doppler matrix; Performing incoherent processing on the second range Doppler matrix, and detecting the incoherent processing result by using the CFAR algorithm to obtain the range Doppler information of the second target; The second target range Doppler information obtained under the sum signal and the second target range Doppler information obtained under the difference signal are used to perform sum and difference angle measurement to determine the long-distance target information.

7. A target detection system based on phased array transmission without blind spots, characterized in that: Applicable to the method according to any one of claims 1 to 6.

8. The target detection system based on phased array non-blind-area transmission as claimed in claim 7, characterized in that: The system includes a signal processing board, an intermediate frequency signal module, an up-conversion module, a power divider, a plurality of transceiver switching components, a summator, a sum-path down-conversion module and a difference-path down-conversion module; Among them, the signal output end of the intermediate frequency signal module is connected to the signal input end of the up-conversion module, the signal output end of the up-conversion module is connected to the signal input end of the power divider, the signal output end of the power divider is connected to the signal input end of each transceiver switching component, each of the transceiver switching components corresponds to the array elements in the first antenna array and the second antenna array one by one and is bidirectionally connected, the signal output end of the transceiver switching component is connected to the signal input end of the summator, the signal output end of the summator is connected to the signal input end of the signal processing board via the summing path down-conversion module and the differential path down-conversion module, and the signal processing board is bidirectionally connected to the intermediate frequency signal module.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

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