Hybrid polarization wave control device with stable antenna system time delay

Abstract

The invention discloses a hybrid polarization wave control device with stable antenna system time delay, and belongs to the technical field of communication signal processing. The device comprises an instruction receiving module, a wave control central control module, a wave control code calculation module and a wave control code sending module. The wave control central control module calculates phase increasing factors in the azimuth direction and the distance direction according to the pointing angle; and the wave control code calculation module calculates the phase shift code of each TR assembly from the geometric center of the antenna, so that the phase shift code of the geometric center of the antenna is fixed to be a half corresponding value of the maximum time delay capability of the system. The wave control code calculation module carries out time division multiplexing, calls H polarization and V polarization ground state error data stored in the same RAM in sequence, calculates H and V polarization channel wave control codes and stores the H and V polarization channel wave control codes in different addresses of the same RAM, and in a left-right rotation circle alternating polarization mode, the wave control code sending module directly carries out 90-degree superposition on linear polarization wave control codes according to PRF parity and then sends the linear polarization wave control codes without repeated calculation. And the PRF frequency is improved.

Description

Technical Field

[0001] This invention belongs to the field of communication signal processing technology, and specifically relates to a hybrid polarization wave control device for time-delay stabilization of an antenna system. Background Technology

[0002] Two-dimensional high-resolution radar imaging technology is commonly referred to as Synthetic Aperture Radar (SAR). Beam control is a crucial component of a SAR system; its primary function is to perform beam scanning and control of the SAR antenna using digital phase shifters, based on the SAR operating mode.

[0003] Hybrid polarization SAR can improve the information acquisition capability of imaging radar for various targets by acquiring more dimensions of target scattering characteristics, containing richer ground feature information. Hybrid polarization modes of radar signals include HH polarization, VV polarization, four-polarization mode, simplified circular polarization, and hybrid simplified circular polarization mode. Hybrid polarization antenna systems contain at least two receiving channels, placing higher demands on the timing and accuracy of the beam control device.

[0004] Traditional beam control code calculation methods typically involve calculating the azimuth phase increment factor (ASPD) and range phase increment factor (RSPD) based on different azimuth and range scanning angles. Then, starting from the antenna's origin, the delay code for each delay component and the phase shift code for each TR component are calculated based on these two phase increment factors and the positional arrangement of the TR components. However, this method has inherent drawbacks: when the beam pointing angle changes, the two-dimensional phase increment factor changes accordingly, and the phase distribution of the antenna system also changes, causing the time delay at the antenna's geometric center to vary with different pointing angles. Therefore, the radar echo reception delay will ultimately change due to different pointing angles. During ground data processing, post-processing compensation for these time delay variations based on different pointing angles is required, increasing processing complexity. This is especially true in hybrid polarized antenna systems, where the presence of at least two receiving channels further complicates ground compensation.

[0005] In addition, the existing beam control devices have relatively simple polarization modes, usually only supporting basic modes such as linear polarization. They cannot meet the information acquisition needs of hybrid polarization SAR imaging radar for various targets, and it is difficult to support flexible switching of multiple working modes such as HH polarization, VV polarization, four polarization, single-rotation circular polarization, and alternating left and right rotation circular polarization that is rapidly switched for each PRF. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a hybrid polarization wave control device for antenna system with stable time delay. Using an FPGA as the core processor, it improves the wave control code calculation method to ensure that the time delay at the antenna geometric center does not change with the pointing angle and supports flexible switching of multiple polarization modes.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A time-delay-stabilized hybrid polarization wave control device for an antenna system, comprising:

[0009] The command receiving module is used to receive beam control commands and antenna pulses;

[0010] The beam control central control module, connected to the command receiving module, is used to read and store the error data of H-polarized antenna and V-polarized antenna according to the error matrix sequence number, and to calculate the azimuth phase increment factor and range phase increment factor according to the pointing angle.

[0011] The beam control code calculation module, connected to the beam control central control module, is used to calculate the theoretical phase shift code of each TR component based on the azimuth phase increment factor, range phase increment factor, TR component position coordinates, and the phase shift code corresponding to half of the maximum time delay capability of the antenna hardware system. This ensures that the phase shift code at the antenna geometric center is fixed to the phase shift code corresponding to half of the system's maximum time delay capability. Then, it combines the H-polarized antenna error data and the V-polarized antenna error data to calculate the final beam control code for the H-polarized channel and the final beam control code for the V-polarized channel, respectively.

[0012] The beam control code transmission module, connected to the beam control code calculation module, is used to serially transmit the final beam control code of the H-polarization channel and the final beam control code of the V-polarization channel to the antenna system.

[0013] Furthermore, the beam control command includes a pointing angle and an error matrix number, and the antenna pulse includes a receive pulse, an H-polarized transmit pulse, and a V-polarized transmit pulse.

[0014] Furthermore, the wave control central control module calculates the azimuth phase increment factor and the range phase increment factor based on the azimuth scanning angle and the range scanning angle in the pointing angle, combined with the center frequency wavelength, the azimuth unit spacing and the range unit spacing.

[0015] Furthermore, the wave control code calculation module calculates the theoretical phase-shift code as follows: taking the phase-shift code corresponding to half of the system's maximum time delay capability as a benchmark, adding the product of the difference between the range coordinate index of the TR component and the range center coordinate and the range phase increment factor, and adding the product of the difference between the azimuth coordinate index of the TR component and the azimuth center coordinate and the azimuth phase increment factor.

[0016] Furthermore, the beam control code calculation module calculates the final beam control code by adding the theoretical phase shift code to the H-polarized antenna error data and the V-polarized antenna error data respectively, to obtain the final beam control code for the H-polarized channel and the final beam control code for the V-polarized channel.

[0017] Furthermore, it also includes a ground-state error memory, wherein the low-address region of the ground-state error memory stores H-polarized antenna error data and the high-address region stores V-polarized antenna error data; the wave control code calculation module is time-division multiplexed, first reading the low-address region to calculate the final wave control code of the H-polarized channel, and then reading the high-address region to calculate the final wave control code of the V-polarized channel.

[0018] Furthermore, it also includes a wave control code memory, which is used to store the calculated final wave control code for the H-polarization channel and the final wave control code for the V-polarization channel, wherein the final wave control code for the H-polarization channel and the final wave control code for the V-polarization channel are stored in different address areas of the same memory.

[0019] Furthermore, the wave control code calculation module employs multiple parallel computing units, each corresponding to a wave control unit, and serially calculates the wave control codes of multiple H-polarization channels and multiple V-polarization channels within that wave control unit.

[0020] Furthermore, the wave control device supports HH polarization and HV polarization modes: H polarization transmit pulses are active, V polarization transmit pulses are inactive, and receive pulses are active;

[0021] The wave control device supports VV polarization and VH polarization modes: V polarization transmit pulse is active, H polarization transmit pulse is inactive, and receive pulse is active.

[0022] The wave control device supports four polarization modes: both H-polarized transmit pulses and V-polarized transmit pulses are active, and the receive pulse is active.

[0023] Furthermore, the wave control device supports single-rotation circular polarization mode: both H-polarization and V-polarization transmit pulses are effective, and receive pulses are effective; in left-hand circular polarization, the final wave control code of the H-polarization channel is 90° added to the online polarization wave control code, and in right-hand circular polarization, the final wave control code of the V-polarization channel is 90° added to the online polarization wave control code;

[0024] The wave control device supports alternating left and right circular polarization modes: the wave control code under linear polarization is pre-calculated and stored. The wave control code sending module, based on the parity of the pulse repetition frequency counter, adds 90° to the final wave control code of the H polarization channel before sending it to achieve left circular polarization when the pulse repetition frequency is odd, and adds 90° to the final wave control code of the V polarization channel before sending it to achieve right circular polarization when the pulse repetition frequency is even.

[0025] The beneficial effects of this invention are as follows:

[0026] First, this invention improves the beam control code calculation method by fixing the phase-shifting code at the antenna's geometric center to half the value corresponding to the system's maximum time delay capability, ensuring that the antenna's geometric center aligns with the phase center. Regardless of changes in the beam pointing angle, the antenna system's time delay remains stable, eliminating the need for post-processing compensation based on different pointing angles in the ground processing system, significantly reducing its complexity. This advantage is particularly prominent in hybrid polarization multi-channel receiving systems, avoiding the difficulties of dual-channel or multi-channel time delay compensation.

[0027] Secondly, this invention uses a time-division multiplexing beam control code calculation module to store the H-polarized antenna ground state error data and the V-polarized antenna ground state error data in different address regions of the same RAM. The calculated H-polarized and V-polarized beam control codes are also stored in different address regions of the same RAM. This design allows the H-polarized and V-polarized channels to share the same calculation module and storage resources, reducing RAM resource consumption by 2×N×M compared to independent design schemes. For hybrid polarization beam control devices of large-scale array antennas, this can significantly reduce the occupation of FPGA logic resources and storage resources, which is beneficial for realizing large array and high integration engineering applications.

[0028] Third, for the alternating left and right circular polarization operating mode, this invention proposes a method of superimposing a 90° phase on the direct online polarization wave control code based on the parity of the PRF. In this mode, it is not necessary to repeatedly trigger the wave control code calculation module in each PRF, avoiding the time overhead caused by repeated calculations, which can significantly shorten the pulse repetition time (PRT) limit, increase the PRF frequency, and support radar operating modes with higher timing requirements.

[0029] Fourth, this invention supports multiple polarization modes, including HH polarization, VV polarization, four-polarization, single-rotation circular polarization, and rapid alternation of left and right rotation circular polarization. The flexible and diverse operating modes can meet the needs of hybrid polarization SAR imaging radar for acquiring multi-dimensional target information. Attached Figure Description

[0030] Figure 1 This is a layout diagram of the hybrid polarization array of the present invention;

[0031] Figure 2 This is a structural diagram of a time-delay-stabilized hybrid polarization wave control device for an antenna system according to the present invention;

[0032] Figure 3 This is a schematic diagram of a time-delay-stabilized hybrid polarization wave control device for an antenna system according to the present invention.

[0033] Figure 4 Schematic diagram of HH polarization and HV polarization operating modes;

[0034] Figure 5Schematic diagram of VV polarization and VH polarization operating modes;

[0035] Figure 6 This is a schematic diagram of the four-polarity working mode;

[0036] Figure 7 This is a schematic diagram of pulse switching and wave control code data in alternating left and right rotation modes;

[0037] Figure 8 This is a schematic diagram of the calculation process for the left-right rotating alternating polarization wave control code. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] This invention provides a time-delay-stable hybrid polarization beam control device for an antenna system, employing a three-stage beam control scheme. The spaceborne SAR beam control device sends full-array beam control data to the antenna system, and the antenna system receives the beam control code data and distributes it to the TR (Transmission Transmission) module. The spaceborne hybrid polarization antenna array layout is as follows: Figure 1 As shown, in a spaceborne hybrid polarization antenna array, a dual-polarization radiating patch is jointly excited by one H-polarized TR component channel and one V-polarized TR component channel. If one wave control unit controls L dual-polarized radiating patches, then that one wave control unit needs to control L H-polarized TR component channels and L V-polarized TR component channels.

[0040] Assuming the full-array spaceborne SAR antenna has N beam control elements in the Y-axis (range direction) and M beam control elements in the X-axis (azimuth direction), then the number of channels for the full-array H-polarized TR module is M. N The L,V polarized TR component has M channels. N L, the number of distance-to-TR channels is N L, the number of azimuth TR channels is M.

[0041] like Figure 2 The diagram shown illustrates the internal module division and external interface of the beam control device of this invention. The FPGA chip, as the core component of the beam control device, is well-suited for parallel processing. M-type FPGAs are used to address the characteristics of large beam arrays. The device comprises N parallel computing modules, each of which serially calculates L H-polarized channel TR components and L V-polarized channel TR components within a wave control unit. The device includes the following modules:

[0042] Command receiving module: Used to receive beam control commands (including pointing angle and error matrix sequence number, etc.) sent by the monitoring period and antenna pulses (receive pulse TR_R, H polarization transmit pulse TR_T_H, V polarization transmit pulse TR_T_V).

[0043] The beam control central control module is used to read TRBE_H (H-polarized antenna error data) and TRBE_V (V-polarized antenna error data) from the memory according to the error matrix sequence number, and write them into the FPGA internal RAM for the calculation module to call; at the same time, it calculates the range phase increment factor RSPD and azimuth phase increment factor ASPD corresponding to the pointing angle in the current instruction according to formula (1):

[0044] Assume different beam directions (azimuth scanning angles) Distance scanning angle The corresponding scanning phase increment factors are as follows:

[0045] (1)

[0046] The scanning phase increment factor obtained by the above formula is in degrees, where and These are the azimuth and range unit spacings, respectively. The center frequency wavelength.

[0047] Beam control code calculation module: This module calculates the theoretical phase shift codes of all TR components in the antenna array according to formula (3), and then, combined with the ground state error data, calculates the final beam control codewords TRTP_H and TRTP_V of all TR components in the antenna array according to formula (4), and stores them in the FPGA's internal RAM for use by the beam control code transmission module. Specifically:

[0048] The theoretical phase-shifting code TRSP for each TR component is calculated based on the array arrangement, where the index k is the range coordinate index of the TR component, and the index v is the azimuth coordinate index of the TR component.

[0049] (2)

[0050] Since the theoretical phase-shift code calculated by formula (2) changes with RSPD and ASPD, the phase-shift code calculated by the geometric center of the array is... The latency of the echo signal received by the antenna array varies with different pointing angles. The ground processing system needs to compensate for this latency according to different pointing angles to accurately reflect the echo latency, thus increasing the complexity of ground processing. Furthermore, in hybrid polarized antenna systems, there are often at least two receiving channels, making compensation even more difficult. Therefore, the TRSP calculation formula is modified as follows:

[0051] (3)

[0052] in This represents half of the maximum time delay capability of the antenna system, ensuring the accuracy of full array calculations. None of them will overflow. According to formula (3), the phase-shifted code calculated by the geometric center of the array is... Fixed equals At this point, regardless of how the beam pointing angle changes, the phase-shift code at the geometric center of the antenna array remains fixed, and the antenna delay does not change with the pointing angle.

[0053] The final wave control code of the TR component is shown in formula (4). Compared with the single-polarization antenna system, the theoretical codes of the two polarizations of the hybrid polarization antenna system are consistent. The difference is that the ground state error code TRBE_H of the H polarization antenna is different from the ground state error code TRBE_V of the V polarization antenna. Therefore, the theoretical code calculation module can be time-division multiplexed to save FPGA logic resource consumption.

[0054] (4)

[0055] Wave control code transmission module: serially transmits the final wave control codeword to the antenna system according to the data protocol.

[0056] The main data interactions between the modules of the beam control device of this invention are as follows: Figure 3 As shown, the H-polarized and V-polarized arrays share the same wave control code calculation module. Each wave control code calculation module calls a ground state error RAM (the lower address region stores TRBE_H, and the higher address region stores TRBE_V). The wave control code calculation module first reads the lower address region TRBE_H when calculating TRTP_H, and then reads the higher address region to calculate TRTP_V after the calculation is complete. This reduces N... M RAM resources. Similarly, the calculated TRTP_H and TRTP_V are also stored in one RAM. This design can reduce a total of 2 N With M RAM resources, the storage requirements for hybrid polarization wave control devices for large-array antennas can be greatly reduced.

[0057] In the steps of calculating and transmitting the wave control code, the H-polarized array and the V-polarized array are processed simultaneously. When the system needs to switch between various polarization modes, it mainly does so by using the antenna to receive the pulse TR_R (which simultaneously enables the receiving channels of the TR components of both the H-polarized and V-polarized arrays), the H-polarized transmit pulse TR_T_H, and the V-polarized transmit pulse TR_T_V in coordination.

[0058] In this invention, the hybrid polarization wave control device supports several common operating modes as follows:

[0059] (1) When the system is in HH polarization and HV polarization, the TR_T_H transmit pulse is active, the TR_T_V transmit pulse is inactive, and the receive pulse TR_R is active. At this time, the system can effectively receive HH linear polarization and HV cross-polarization echo signals. The pulse switching is as follows: Figure 4 As shown.

[0060] (2) When the system is in VV polarization or VH polarization, the TR_T_V transmit pulse is active, the TR_T_H transmit pulse is inactive, and the receive pulse TR_R is active. At this time, the system can effectively receive VV linear polarization and VH cross-polarization echo signals. The pulse switching is as follows: Figure 5 As shown.

[0061] (3) When the system is in four-polarization mode, the TR_T_V transmit pulse is active, the TR_T_H transmit pulse is active, and the receive pulse TR_R is active. At this time, the system can effectively receive HH linear polarization, VV linear polarization, VH cross-polarization and HV cross-polarization echo signals. The pulse switching is as follows: Figure 6 As shown.

[0062] (4) When the system is in left-hand circular polarization mode or right-hand circular polarization, the TR_T_V transmit pulse is active, the TR_T_H transmit pulse is active, and the TR_R receive pulse is active. The pulse switching is as follows: Figure 6 As shown. Left-handed circular polarization is based on the online polarization with the TRTP_H codeword plus 90°, and right-handed circular polarization is based on the online polarization with the TRTP_V codeword plus 90°.

[0063] (5) When the system is in alternating left and right circular polarization, the TR_T_V transmit pulse is active, the TR_T_H transmit pulse is active, and the TR_R receive pulse is active. The pulse switching and wave control code data are as follows: Figure 7 As shown. In this working state, each PRF needs to be re-deployed. If the beam control code is recalculated each time, the calculation time plus the beam control code transmission time must be less than the PRT. In this case, the PRT will be quite limited, and the time will be very long.

[0064] Since left-hand circular polarization only increases the phase by 90° compared to linear polarization, the wave control code under linear polarization conditions can be pre-calculated and stored in N. In M RAMs, the wave control code calculation module is not triggered during subsequent PRF alternation operations to avoid repeated calculations. For example... Figure 8 As shown, in the wave control code transmission module, the parity of the PRF counter is determined. For odd-numbered PRFs, 90° is added to the TRTP_H read from RAM before transmission, achieving left-hand circular polarization. For even-numbered PRFs, 90° is added to the TRTP_V read from RAM before transmission, achieving right-hand circular polarization. This eliminates the time consumed by wave control code calculation, significantly shortens the PRT limitation, and increases the PRF frequency.

[0065] If a simple linearly polarized waveguide device uses a VIRTEX5 chip to control a 1000-channel TR array, it consumes approximately 45% of RAM resources. If a conventional dual-polarized waveguide device is used to control a dual-polarized array antenna with 1000 H-polarized and 1000 V-polarized TR channels, it consumes 65% of RAM resources. Using the method described in this invention, RAM resources are increased by only 5%.

[0066] In summary, the present invention proposes a time-delay-stable hybrid polarization wave control device for antenna systems. It achieves time-delay stability by improving the wave control code calculation method, reduces resource consumption through time-division multiplexing and shared storage, and realizes rapid left-right rotational alternation polarization by pre-stored linear polarization codewords plus 90°. It effectively supports multiple operating modes such as HH polarization, VV polarization, four polarizations, single-rotation circular polarization, and left-right rotational alternation polarization, and is suitable for hybrid polarization SAR imaging radar systems.

[0067] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A time-delay-stabilized hybrid polarization wave control device for an antenna system, characterized in that, include: The command receiving module is used to receive beam control commands and antenna pulses; The beam control central control module, connected to the command receiving module, is used to read and store the error data of H-polarized antenna and V-polarized antenna according to the error matrix sequence number, and to calculate the azimuth phase increment factor and range phase increment factor according to the pointing angle. The beam control code calculation module, connected to the beam control central control module, is used to calculate the theoretical phase shift code of each TR component based on the azimuth phase increment factor, range phase increment factor, TR component position coordinates, and the phase shift code corresponding to half of the maximum time delay capability of the antenna hardware system. This ensures that the phase shift code at the antenna geometric center is fixed to the phase shift code corresponding to half of the system's maximum time delay capability. Then, it combines the H-polarized antenna error data and the V-polarized antenna error data to calculate the final beam control code for the H-polarized channel and the final beam control code for the V-polarized channel, respectively. The beam control code transmission module, connected to the beam control code calculation module, is used to serially transmit the final beam control code of the H-polarization channel and the final beam control code of the V-polarization channel to the antenna system.

2. The time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The beam control command includes the pointing angle and the error matrix number, and the antenna pulse includes the receive pulse, the H-polarized transmit pulse, and the V-polarized transmit pulse.

3. The time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The wave control central control module calculates the azimuth phase increment factor and the range phase increment factor based on the azimuth scanning angle and the range scanning angle in the pointing angle, combined with the center frequency wavelength, the azimuth unit spacing and the range unit spacing.

4. The time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The waveform control code calculation module calculates the theoretical phase-shift code as follows: taking the phase-shift code corresponding to half of the system's maximum time delay capability as a benchmark, adding the product of the difference between the range coordinate index of the TR component and the range center coordinate and the range phase increment factor, and adding the product of the difference between the azimuth coordinate index of the TR component and the azimuth center coordinate and the azimuth phase increment factor.

5. The time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The beam control code calculation module calculates the final beam control code by adding the theoretical phase shift code to the H-polarized antenna error data and the V-polarized antenna error data respectively, to obtain the final beam control code for the H-polarized channel and the final beam control code for the V-polarized channel.

6. The time-delay stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, It also includes a ground-state error memory, in which the low-address region stores H-polarized antenna error data and the high-address region stores V-polarized antenna error data; the wave control code calculation module is time-division multiplexed, first reading the low-address region to calculate the final wave control code of the H-polarized channel, and then reading the high-address region to calculate the final wave control code of the V-polarized channel.

7. The time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, It also includes a wave control code memory, which is used to store the calculated final wave control code for the H-polarization channel and the final wave control code for the V-polarization channel, wherein the final wave control code for the H-polarization channel and the final wave control code for the V-polarization channel are stored in different address areas of the same memory.

8. A time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The wave control code calculation module employs multiple parallel computing units, each corresponding to a wave control unit, which serially calculates the wave control codes for multiple H-polarization channels and multiple V-polarization channels within the wave control unit.

9. A time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The wave control device supports HH polarization and HV polarization modes: H polarization transmit pulse is active, V polarization transmit pulse is inactive, and receive pulse is active; The wave control device supports VV polarization and VH polarization modes: V polarization transmit pulse is active, H polarization transmit pulse is inactive, and receive pulse is active. The wave control device supports four polarization modes: both H-polarized transmit pulses and V-polarized transmit pulses are active, and the receive pulse is active.

10. A time-delay-stabilized hybrid polarization wave control device for an antenna system according to claim 1, characterized in that, The wave control device supports single-rotation circular polarization mode: both H-polarization and V-polarization transmit pulses are effective, and receive pulses are effective; when left-hand circular polarization is used, the final wave control code of the H-polarization channel is added 90° to the online polarization wave control code, and when right-hand circular polarization is used, the final wave control code of the V-polarization channel is added 90° to the online polarization wave control code; The wave control device supports alternating left and right circular polarization modes: the wave control code under linear polarization is pre-calculated and stored. The wave control code sending module, based on the parity of the pulse repetition frequency counter, adds 90° to the final wave control code of the H polarization channel before sending it to achieve left circular polarization when the pulse repetition frequency is odd, and adds 90° to the final wave control code of the V polarization channel before sending it to achieve right circular polarization when the pulse repetition frequency is even.

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