A spaceborne SAR antenna device and control method for simultaneous dual-side-view imaging

Abstract

This invention proposes a novel spaceborne SAR antenna device and control method for simultaneous dual-side-looking imaging, thus meeting the application requirements of simultaneous dual-side-looking imaging of the Earth. The antenna system is a phased array system with a wide-range electronic scanning capability. It employs one transmit / receive link, one receive-only link, and one calibration link. Through an improved beam control code configuration and timing control method, simultaneous observation and imaging of both left and right sides is achieved. This invention achieves simultaneous dual-side-looking imaging of the Earth without requiring satellite platform attitude maneuvers, effectively improving system performance.

Description

Technical Field

[0001] This invention belongs to the field of spaceborne synthetic aperture radar antenna technology, specifically relating to a spaceborne SAR antenna device and control method for simultaneous dual-side-view imaging. Background Technology

[0002] Spaceborne synthetic aperture radar features all-weather, all-day imaging capabilities and has wide applications in the national economy and defense sectors.

[0003] Conventional spaceborne synthetic aperture radars operate in a single-side-look mode. The antenna system's normal relative to the satellite's nadir point has a tilt angle to the left (left-side look) or right (right-side look). At any given time, only single-side-look observation and imaging requirements can be met. Figure 1 As shown.

[0004] To achieve the switching between left and right-facing operating modes, the antenna system's attitude towards the ground must be adjusted by maneuvering the satellite platform, which is time-consuming. Figure 2 As shown.

[0005] For single-view imaging, the antenna system contains only one transmit / receive link and one calibration link, such as Figure 3 As shown.

[0006] Its beam control code configuration method and beam control system timing control method, such as Figure 4a , Figure 4b As shown. The first-level buffer stores the beam control code for the currently active waveform (left or right view), including the transmit phase shift code, receive phase shift code, and receive attenuation code. Each TR channel is configured with one phase shifter and one attenuator. The phase shifter is shared by both the transmit and receive phase shift codes, and the timing signal TR_R is used to switch between them. The attenuator is dedicated to the receive attenuation code. The second-level buffer pre-stores the beam control code for the next active waveform (left or right view), including the transmit phase shift code, receive phase shift code, and receive attenuation code. When the next active waveform needs to be activated, the timing signal SET switches the beam control code from the second-level buffer to the first-level buffer, completing the waveform switching. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a novel spaceborne SAR antenna device and control method for simultaneous dual-side-looking imaging. This novel spaceborne synthetic aperture radar antenna device meets the application requirements for simultaneous dual-side-looking imaging of the Earth. The antenna system is a phased array system with a wide-range electronic scanning capability. It employs one transmit / receive link, one receive-only link, and one calibration link. Through an improved beam control code configuration and timing control method, simultaneous observation and imaging of both left and right sides is achieved. This invention eliminates the need for satellite platform attitude maneuvers, enabling simultaneous dual-side-looking imaging of the Earth and effectively improving system performance.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A spaceborne SAR antenna device for simultaneous dual-side-looking imaging, wherein the normal of the antenna device coincides with the direction of the satellite's nadir point, and a phased array system is adopted; the antenna device is configured with one transmit / receive link, one receive-only link, and one calibration link;

[0010] The transmit / receive link consists of transmit / receive branches in delay amplification components at each stage, transmit / receive radio frequency power dividers at each stage, and transmit / receive branches in TR components, and has both signal transmission and reception functions;

[0011] The receive-only link consists of receive-only branches in each stage of delay amplification components, receive-only RF power dividers in each stage, and receive-only branches in the TR component, to realize the function of receiving echo signals.

[0012] The calibration link consists of calibration power dividers at various levels, used to assist in completing the on-orbit calibration functions of the transmit / receive link and the receive-only link;

[0013] Within one pulse repetition cycle, the transmit branch in the transmit / receive link is used to transmit signals from the left and right view positions in a time-division manner; the receive branch and the receive-only link in the transmit / receive link are used to receive echo signals from the left and right view positions simultaneously.

[0014] Furthermore, in each delay amplification component, each delay amplification component is equipped with two delay units, one for the transmit / receive branch and one for the receive-only branch.

[0015] Furthermore, in the TR component, each channel is equipped with 2 phase shifters and 2 attenuators, wherein the transmit / receive branch of the TR component is equipped with 1 phase shifter and 1 attenuator, and the receive-only branch of the TR component is equipped with 1 phase shifter and 1 attenuator.

[0016] Furthermore, in the TR component, the transmit / receive branch and the receive-only branch share the same set of circulators, limiters, and low-noise amplifiers; at the back end of the low-noise amplifier, the received signal is divided into two paths by a 1:2 power divider. One path is modulated by the phase shifter and attenuator of the transmit / receive branch in the TR component to receive the echo signal of the left viewpoint position signal; the other path is modulated by the phase shifter and attenuator of the receive-only branch in the TR component to receive the echo signal of the right viewpoint position signal.

[0017] This invention also provides a control method for a spaceborne SAR antenna device with simultaneous dual-side viewing imaging, comprising: a first-level buffer storing the beam control codes for the two currently active left and right viewing positions, including the left viewing position transmit phase shift code, the left viewing position receive phase shift code, the left viewing position receive attenuation code, the right viewing position transmit phase shift code, the right viewing position receive phase shift code, and the right viewing position receive attenuation code; each TR component has two phase shifters and two attenuators configured in its channel, and the corresponding beam control codes are configured through timing signals; a second-level buffer pre-stores the beam control codes for the subsequent working left and right viewing positions, including the left viewing position transmit phase shift code, the left viewing position receive phase shift code, the left viewing position receive attenuation code, the right viewing position transmit phase shift code, the right viewing position receive phase shift code, and the right viewing position receive attenuation code; when the subsequent working left and right viewing positions need to be switched to active status, the beam control codes in the second-level buffer are switched into the first-level buffer through the timing signal SET, completing the beam switching.

[0018] Beneficial effects:

[0019] The present invention proposes a spaceborne SAR antenna device and control method for simultaneous dual-side-view imaging, which can meet the application requirements of simultaneous dual-side-view observation and imaging of the ground, while eliminating the need for satellite platform attitude maneuvering, thus effectively improving the system's working efficiency. Attached Figure Description

[0020] Figure 1 Schematic diagram of the installation posture and viewing angle coverage of a conventional single-sided viewing imaging antenna device;

[0021] Figure 2 Schematic diagram of left / right side view attitude maneuvering of a conventional single-sided view imaging antenna device;

[0022] Figure 3 Schematic diagram of the radio frequency signal link of a conventional single-sided viewing imaging antenna device;

[0023] Figure 4a , Figure 4b This diagram illustrates the beam control code configuration and timing control method of a conventional single-sided viewing imaging antenna device; where... Figure 4a For timing control methods of waveguide systems, Figure 4b For wave control code configuration method;

[0024] Figure 5 Schematic diagram of the installation posture and viewing angle coverage of the dual-side-view imaging antenna device;

[0025] Figure 6 Schematic diagram of the radio frequency signal link of the dual-side-view imaging antenna device;

[0026] Figure 7. Schematic diagram of the beam control code configuration and timing control method of the beam control system for the dual-side-view imaging antenna device; where... Figure 7a For timing control methods of waveguide systems, Figure 7b This is the configuration method for wave control codes. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0028] like Figure 5 As shown, the normal direction of the spaceborne SAR antenna device for simultaneous dual-side imaging of the present invention coincides with the direction of the satellite's nadir point. It adopts a phased array system and the antenna device has a wide range electronic scanning capability in the range direction. It can achieve simultaneous coverage of the imaging area of ​​the target on both sides without the need for satellite platform attitude maneuvering.

[0029] like Figure 6 As shown, the antenna device is configured with one transmit / receive link, one receive-only link, and one calibration link. Within one pulse repetition period (PRT), the transmit branch in the transmit / receive link is used to achieve time-division multiplexing of signal transmission for the left and right view positions; the receive branch and the receive-only link in the transmit / receive link are used to simultaneously achieve signal reception for the left and right view positions.

[0030] like Figure 7a , Figure 7bAs shown, the improved beam control code configuration method and beam control system timing control method include: A primary buffer stores the beam control codes for the two currently active beam positions (left and right view beam positions), including the transmit phase shift code, receive phase shift code, and receive attenuation code for the left view beam position; the transmit phase shift code, receive phase shift code, and receive attenuation code for the right view beam position; and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, and the receive phase shift code, are used. When the two subsequent active beam positions need to be switched to active status, the beam control codes in the secondary buffer are switched into the primary buffer through the timing signal SET, and the beam position switching is completed.

[0031] To meet the application requirements of simultaneous dual-side imaging of the earth, the present invention mainly adopts the following measures:

[0032] (1) Improve antenna range beam scanning capability:

[0033] The antenna device's normal direction coincides with the satellite's nadir direction. Employing a phased array system, it reduces the spacing between range-oriented antenna elements, enabling the antenna device to perform wide-range electronic scanning. This allows for simultaneous coverage of target imaging areas on both sides without requiring satellite platform attitude maneuvers. Figure 5 As shown.

[0034] (2) Antenna device hardware link configuration:

[0035] The antenna device is configured with one transmit / receive link, one receive-only link, and one calibration link.

[0036] The transmit / receive link mainly consists of transmit / receive branches in delay amplifiers at various levels, RF power dividers (transmit / receive) at various levels, and transmit / receive branches in TR components, and has both signal transmission and reception functions.

[0037] The receive-only link mainly consists of the receive-only branch in each stage of delay amplification components, the receive-only branch in each stage of RF power divider, and the receive-only branch in the TR component, which can realize the function of receiving echo signals.

[0038] The calibration link mainly consists of calibration power dividers at various levels, which are used to assist in completing the on-orbit calibration function of the transmit / receive link and the receive-only link.

[0039] Within one pulse repetition cycle (PRT), the transmit branch in the transmit / receive link is used to time-division multiplex the signal transmission to the left and right view positions; the receive branch and the receive-only link in the transmit / receive link are used to simultaneously receive the echo signals from the left and right view positions, such as... Figure 6 As shown.

[0040] In each stage of the delay amplification component, each delay amplification component is equipped with 2 delay units, one for the transmit / receive branch and one for the receive-only branch.

[0041] In the TR component, each channel is equipped with 2 phase shifters and 2 attenuators, with the transmit / receive branch equipped with 1 phase shifter and 1 attenuator, and the receive-only branch equipped with 1 phase shifter and 1 attenuator.

[0042] In addition, in the TR module, the transmit / receive branch and the receive-only branch share the same set of circulators, limiters, and low-noise amplifiers. A 1:2 power divider splits the received signal into two paths after the low-noise amplifier. One path is modulated by the phase shifter and attenuator of the transmit / receive branch to receive the echo signal of the left viewpoint; the other path is modulated by the phase shifter and attenuator of the receive-only branch to receive the echo signal of the right viewpoint.

[0043] The transmit / receive branch shares the same set of circulators, limiters, and low-noise amplifiers as the receive-only branch, which can reduce the cost of TR components and reduce their size and weight.

[0044] (3) Improved beam control code configuration method and beam control system timing control method, such as Figure 7a , Figure 7b As shown.

[0045] TR_R1 is the left viewpoint reception control timing, active high; TR_R2 is the right viewpoint reception control timing, active high; TR_T1 is the left viewpoint transmission control timing, active low; TR_T2 is the right viewpoint transmission control timing, active low; RF is a radio frequency signal diagram (within each pulse repetition period PRT, there are 2 working wave positions corresponding to the left and right viewpoints, with 2 radio frequency RF pulse signals).

[0046] To achieve near real-time waveform updates for the antenna device, two levels of buffers (first-level buffer and second-level buffer) are configured for the delay, phase shifter and attenuator in the antenna link.

[0047] The present invention will now be described in detail using the TR component as an example.

[0048] The first-level cache stores the wave control codes for the two currently active wave positions (left view wave position and right view wave position), including the transmit phase shift code, receive phase shift code, and receive attenuation code for the left view wave position, as well as the transmit phase shift code, receive phase shift code, and receive attenuation code for the right view wave position.

[0049] Each TR component has two phase shifters and two attenuators configured in its channel, and the corresponding wave control codes are configured through timing signals.

[0050] The first attenuator is dedicated to receiving attenuation codes at the left viewpoint; the second attenuator is dedicated to receiving attenuation codes at the right viewpoint; and the second phase shifter is dedicated to receiving phase-shift codes at the right viewpoint 2.

[0051] The first phase shifter is shared by the left viewpoint transmit phase shift code, the left viewpoint receive phase shift code, and the right viewpoint transmit phase shift code. When TR_R1 is high, and TR_T1 and TR_T2 are also high, the left viewpoint receive phase shift code is active; when TR_T1 is low, TR_R1 is low, and TR_T2 is high, the left viewpoint transmit phase shift code is active; when TR_T2 is low, TR_R1 is low, and TR_T1 is high, the right viewpoint transmit phase shift code is active.

[0052] Based on the timing control described above, within one pulse repetition cycle (PRT), during the low level of TR_T1, the RF signal transmission for the left viewpoint is completed; during the low level of TR_T2, the RF signal transmission for the right viewpoint is completed. The two RF signals share the transmit branch in the transmit / receive link and are transmitted in a time-division manner through timing control. During the high levels of TR_R1 and TR_R2, the signal reception for the left and right viewpoints is completed. The two positions are simultaneously received using the receive branch in the transmit / receive link and the receive-only link, respectively.

[0053] The secondary buffer pre-stores the wave control codes for the next two working wave positions (left view wave position and right view wave position), including the transmit phase shift code, receive phase shift code, and receive attenuation code for the left view wave position, the transmit phase shift code, the receive phase shift code, and the receive attenuation code for the right view wave position.

[0054] CLK1 is the waveform control code transmission clock signal; DataA is the waveform control code data for the next two waveforms; DEN1 is the waveform control code transmission enable signal; under the action of these three signals, the secondary buffer waveform control code is updated. This update process does not affect the normal operation of the currently working two waveforms.

[0055] When the next two working waveforms need to be switched to the active state, the waveform control code in the secondary buffer is switched into the primary buffer through the timing signal SET to complete the working waveform update.

[0056] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A space-borne SAR antenna device for simultaneous bilateral vision imaging, characterized by: The normal of the antenna device coincides with the direction of satellite subsatellite point, and the antenna device adopts phased array system; the antenna device is configured with a receiving / transmitting link, a receiving only link and a scaling link; The receiving / transmitting link is composed of receiving / transmitting branches in each delay amplification component, each level receiving / transmitting frequency divider and receiving / transmitting branches in the TR component, and simultaneously has the functions of signal transmission and reception; The receiving only link is composed of receiving only branches in each delay amplification component, each level receiving only frequency divider and receiving only branches in the TR component, and realizes the function of echo signal reception; The scaling link is composed of each level scaling power divider, and is used to assist the on-orbit scaling function of the receiving / transmitting link and the receiving only link; In one pulse repetition period, the transmission branches in the receiving / transmitting link are used to realize the signal transmission of the left and right side wave positions in time sharing mode; the receiving branches in the receiving / transmitting link and the receiving only link are used to realize the echo signal reception of the left and right side wave positions simultaneously.

2. The space-borne SAR antenna device of simultaneous bilateral vision imaging according to claim 1, characterized in that: In each delay amplification component, two delay devices are equipped inside each delay amplification component, wherein one is equipped in the receiving / transmitting branch in each delay amplification component, and the other is equipped in the receiving only branch in each delay amplification component.

3. The space-borne SAR antenna device of simultaneous bilateral vision imaging according to claim 1, characterized in that: In the TR component, two phase shifters and two attenuators are equipped in each channel, wherein one phase shifter and one attenuator are equipped in the receiving / transmitting branch in the TR component, and the other phase shifter and the other attenuator are equipped in the receiving only branch in the TR component.

4. The space-borne SAR antenna device of simultaneous bilateral view imaging according to claim 3, characterized in that: In the TR component, the receiving / transmitting branch and the receiving only branch share the same set of circulators, limiters and low noise amplifiers; the receiving signal is divided into two paths through a 1:2 power divider at the back end of the low noise amplifier, one path is modulated through the phase shifter and the attenuator of the receiving / transmitting branch in the TR component to realize the reception of the left side wave position signal echo signal, and the other path is modulated through the phase shifter and the attenuator of the receiving only branch in the TR component to realize the reception of the right side wave position signal echo signal.

5. A method of controlling a simultaneous dual side-looking imaging space-borne SAR antenna device according to one of claims 1 to 4, characterized in that The first level cache stores the current two effective left and right side wave position wave control codes, including the left side wave position transmission phase shift code, the left side wave position reception phase shift code, the left side wave position reception attenuation code, the right side wave position transmission phase shift code, the right side wave position reception phase shift code and the right side wave position reception attenuation code; two phase shifters and two attenuators are configured in each channel of each TR component to complete the configuration of the corresponding wave control code through timing signals; the second level cache pre-stores the wave control codes of the left and right side wave positions for subsequent work, including the left side wave position transmission phase shift code, the left side wave position reception phase shift code, the left side wave position reception attenuation code, the right side wave position transmission phase shift code, the right side wave position reception phase shift code and the right side wave position reception attenuation code; when the left and right side wave positions for subsequent work need to be switched into the effective state, the wave control codes in the second level cache are switched into the first level cache through timing signals SET to complete the wave position switching.

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