Synthetic aperture radar imaging control device integrating multiple image acquisition modes

Abstract

The invention belongs to the technical field of radar imaging acquisition, and particularly relates to a synthetic aperture radar imaging control device integrating multiple image acquisition modes, which comprises a comprehensive digital processing module and an SAR antenna, the SAR antenna is connected with a comprehensive radio frequency module, and the SAR antenna is in data transmission connection with the comprehensive digital processing module through the comprehensive radio frequency module. The SAR antenna target is subjected to microwave imaging and has the capability of outputting imaging image data and imaging original analog data, imaging modes comprise a strip mode, a scanning mode and a bunching mode, and image acquisition is carried out based on the multiple imaging modes. Advanced design and processing technologies are adopted for all single machines of the system, the system integration degree is improved, functions are fused, the system weight is reduced, integrated design is achieved, system composition is simplified by optimizing and combining system control functions, and the system integration degree is further improved by adopting a large-scale high-integration-degree programmable device.

Description

Technical Field

[0001] The present invention relates to the field of radar imaging technology, and in particular to a synthetic aperture radar imaging control device integrating multiple image acquisition modes. Background Art

[0002] Radar satellite (SAR radar) is a general term for earth observation remote sensing satellites equipped with synthetic aperture radar (SAR). Defense and commercial aerospace have an increasing demand for small SAR remote sensing satellites and high-resolution SAR payloads.

[0003] However, key technologies such as lightweight two-dimensional phased-scanned array antenna technology, onboard SAR real-time imaging, and detection still have defects and have not been resolved.

[0004] At present, small SAR remote sensing satellites and high-resolution SAR payloads have not made breakthroughs in key technologies such as lightweight two-dimensional phased-scanned phased array antenna technology, on-board SAR real-time imaging, and detection. Summary of the invention

[0005] The purpose of the present invention is to provide a synthetic aperture radar imaging control device that integrates multiple image acquisition modes to solve the problem that small SAR remote sensing satellites and high-resolution SAR payloads proposed in the above background technology have not made breakthroughs in key technologies such as lightweight two-dimensional phased-scan phased array antenna technology, on-board SAR real-time imaging, and detection.

[0006] To achieve the above object, the present invention provides the following technical solution: a synthetic aperture radar imaging control device integrating multiple image acquisition modes, comprising:

[0007] Integrated digital processing module, SAR antenna;

[0008] Wherein, the SAR antenna establishes a connection with the integrated radio frequency module, and the SAR antenna establishes a data transmission connection with the integrated digital processing module through the integrated radio frequency module;

[0009] The SAR antenna target performs microwave imaging and has the ability to output imaging image data and imaging raw analog data. The imaging modes include strip mode, scanning mode and beamforming mode, and image acquisition is performed based on the above multiple imaging modes;

[0010] The integrated digital processing module completes SAR payload data management, intermediate frequency transmission signal generation, receiving multi-channel data acquisition, timing control function, and beam control function. The integrated digital processing module is a time reference, which is used to ensure the synchronization of the system's receiving and transmitting work, and at the same time executes the ground remote control and telemetry tasks for the SAR subsystem.

[0011] Preferably, the strip mode is specifically: the SAR antenna aims at a designated ground strip to perform continuous acquisition.

[0012] Preferably, the scanning mode is specifically: a mode of achieving large-strip coverage through electronic beam control, and within the coverage range, multiple sub-bands are used to increase the imaging width.

[0013] Preferably, the beamforming mode is specifically: by controlling the SAR antenna azimuth to point the antenna beam so that it continuously illuminates the target area to obtain a longer synthetic aperture time, and obtain a high-resolution image in a small area that cannot be achieved by an ordinary strip mode.

[0014] Preferably, during the entire synthetic aperture time, the radar antenna continuously adjusts its direction to always illuminate the same area on the ground.

[0015] Preferably, the SAR antenna further comprises:

[0016] Capability of continuous imaging of multiple point targets in a region;

[0017] Two-dimensional scanning capability, capable of acquiring SAR images with 0.5m spatial resolution and high signal-to-noise ratio in staring spotlight mode;

[0018] 2-channel transceiver in azimuth and single-channel transceiver in elevation;

[0019] In-load calibration system;

[0020] Large angle beam scanning capability;

[0021] Transmitted signal power amplification and radiation function;

[0022] Echo signal receiving and low noise amplification functions;

[0023] Self-safety protection functions such as over duty cycle, over pulse width, over current, short circuit, etc.

[0024] Raw radar echo data on-board real-time imaging, target detection, target slice extraction and other processing functions;

[0025] Software note update function;

[0026] Telemetry data collection and upload function.

[0027] Preferably, the integrated RF module includes a clock / transmitting module, a receiving module, and an internal calibration module. The transmitting and receiving networks of the SAR antenna are connected to the receiving module, the calibration network of the SAR antenna is connected to the internal calibration module, and the clock / transmitting module, the receiving module, and the internal calibration module are connected to each other.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] It has the ability to output imaging image data and imaging raw simulation data. The imaging modes include strip mode, scanning mode (including TOPS mode) and beam mode. It completes the overall design of lightweight and high-resolution SAR payload and develops SAR payload engineering prototype, providing strong support for building a lightweight and agile reconnaissance remote sensing system with high performance indicators and rapid response.

[0030] The integrated digital processing module mainly completes SAR payload data management, intermediate frequency transmission signal generation, receiving multi-channel data acquisition, timing control function, beam control function and other functions. It is the time base of the SAR subsystem and is used to ensure the synchronization of the system's receiving and transmitting work. At the same time, it performs ground remote control and telemetry tasks for the SAR subsystem.

[0031] Advanced design and processing technologies are adopted for each unit of the system to improve system integration, integrate functions and reduce system weight. Through optimized design, the system is divided according to functions, and similar functions are integrated; SAR real-time signal processing and signal acquisition are integrated to simplify system high-speed data interconnection and improve data transmission reliability; integrated design simplifies system composition by optimizing and combining system control functions, and adopts large-scale high-integration programmable devices to further improve system integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a system logic block diagram of the present invention;

[0033] Figure 2 For the present invention Figure 1 A further decomposed logic block diagram. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] Embodiment 1:

[0037] See also Figure 1-2The present invention provides a technical solution: a synthetic aperture radar imaging control device integrating multiple image acquisition modes, comprising:

[0038] Integrated digital processing module, SAR antenna;

[0039] Wherein, the SAR antenna establishes a connection with the integrated radio frequency module, and the SAR antenna establishes a data transmission connection with the integrated digital processing module through the integrated radio frequency module;

[0040] The SAR antenna target performs microwave imaging and has the ability to output imaging image data and imaging raw analog data. The imaging modes include strip mode, scanning mode and beamforming mode, and image acquisition is performed based on the above multiple imaging modes;

[0041] The integrated digital processing module completes SAR payload data management, intermediate frequency transmission signal generation, receiving multi-channel data acquisition, timing control function, and beam control function. The integrated digital processing module is a time reference, which is used to ensure the synchronization of the system's receiving and transmitting work, and at the same time executes the ground remote control and telemetry tasks for the SAR subsystem.

[0042] The main working mode of the light and small high-resolution SAR payload system is the SAR ground remote sensing observation mode. When the SAR payload works, it can conduct remote sensing observation of the ground and obtain high-resolution radar images similar to optical photography under extremely poor visibility weather conditions.

[0043] The SAR payload can control the SAR payload working mode through ground injection numbers on orbit. The SAR payload has five working modes, namely 0.5m / 5kmх5km and 1m / 10kmх10km sliding beam mode, 2m / 20kmх20km strip mode, 10m / 100km TOPS mode, and 15m / 150km TOPS mode. The SAR is powered on in the default 2m / 20km mode.

[0044] In order to achieve the lightweight index requirements, the high-resolution wideband payload consists of a SAR antenna and central electronic equipment, and its composition block diagram is shown in the figure below. The central electronic equipment includes a power distribution module, an integrated digital processing module, and an integrated radio frequency module. The integrated radio frequency module consists of a clock / transmitter module, a receiver module, and an internal calibration module.

[0045] The SAR antenna array is designed to have a size of 4608mm*704mm, which can transmit SAR broadband signals and receive echo signals.

[0046] The RF module in the central electronic equipment integrates functional modules such as the clock / transmitter module, radar receiving module, and internal calibration. It is responsible for generating the radar reference frequency and clock signal, and realizing the amplification, filtering, and amplitude adjustment of the radar echo receiving signal.

[0047] The integrated digital processing module in the central electronic equipment mainly completes SAR payload data management, intermediate frequency transmission signal generation, receiving multi-channel data acquisition, timing control function, beam control function and other functions. It is the time base of the SAR subsystem and is used to ensure the synchronization of the system's receiving and transmitting work, while performing ground remote control and telemetry tasks for the SAR subsystem.

[0048] The real-time imaging processing module has the ability to complete SAR imaging, target detection, positioning and parameter extraction on-orbit.

[0049] In order to achieve the lightweight and high efficiency of the entire system and meet the stringent weight requirements, it is necessary to adopt advanced design and processing technologies for each unit of the system to improve system integration, integrate functions, and reduce system weight. Through optimized design, the system is divided by function, and similar functions are merged; SAR real-time signal processing and signal acquisition are integrated to simplify the system's high-speed data interconnection and improve data transmission reliability; the monitoring timer and beam controller are integrated to simplify the system composition by optimizing the combined system control function, and large-scale high-integration programmable devices are used to further improve system integration.

[0050] Embodiment 2:

[0051] See also Figure 1-2 , the present invention provides a technical solution:

[0052] The strip mode is specifically: the SAR antenna aims at a designated ground strip to perform continuous acquisition.

[0053] Through electronic beam control, a large-strip coverage mode is achieved. Within the coverage range, multiple sub-bands are used to increase the imaging width.

[0054] The beamforming mode is specifically: by controlling the SAR antenna azimuth direction antenna beam pointing, so that it continuously illuminates the target area to obtain a longer synthetic aperture time, and obtain a high-resolution image in a small area that cannot be achieved by ordinary strip mode. During the entire synthetic aperture time, the radar antenna continuously adjusts its direction to always illuminate the same area on the ground.

[0055] The SAR antenna also has:

[0056] Capability of continuous imaging of multiple point targets in a region;

[0057] Two-dimensional scanning capability, capable of acquiring SAR images with 0.5m spatial resolution and high signal-to-noise ratio in staring spotlight mode;

[0058] 2-channel transceiver in azimuth and single-channel transceiver in elevation;

[0059] In-load calibration system;

[0060] Large angle beam scanning capability;

[0061] Transmitted signal power amplification and radiation function;

[0062] Echo signal receiving and low noise amplification functions;

[0063] Self-safety protection functions such as over duty cycle, over pulse width, over current, short circuit, etc.

[0064] Raw radar echo data on-board real-time imaging, target detection, target slice extraction and other processing functions;

[0065] Software note update function;

[0066] Telemetry data collection and upload function.

[0067] Embodiment three:

[0068] See also Figure 1-2 The present invention provides a technical solution: the integrated radio frequency module includes a clock / transmitting module, a receiving module, and an internal calibration module; the transmitting and receiving networks of the SAR antenna are connected to the receiving module; the calibration network of the SAR antenna is connected to the internal calibration module; and the clock / transmitting module, the receiving module, and the internal calibration module are connected to each other.

[0069] It is responsible for generating radar reference frequency and clock signal, and realizing amplification, filtering and amplitude adjustment of radar echo receiving signal. The real-time imaging processing module has the ability to complete SAR imaging, target detection, positioning and parameter extraction on orbit.

[0070] The imaging processing module mainly completes SAR imaging. Currently, GPU, FPGA and DSP are widely used in radar digital signal processing. These three platforms have powerful signal processing capabilities and their own scope of application. Generally speaking, GPU has the strongest processing power. GPU can have thousands or even tens of thousands of stream processing cores, support floating-point operations, and excel in parallel computing. However, it has high power consumption and weak control capabilities. It has no advantage in executing algorithms with complex calculation steps and is widely used in machine learning. As a programmable logic device, FPGA implements user logic by changing internal logic blocks and wiring. In addition, current high-end FPGAs are embedded with a large number of dedicated DSP units and block storage units, and have strong processing capabilities. Although the system operating clock is relatively low, as long as there are sufficient resources, the FPGA processing capability can be enhanced by exchanging area for speed through pipelining and parallelization, thereby reducing processing time. However, its cost is relatively high and its development difficulty is relatively large. For example, when transplanting an algorithm, it is necessary to first perform fixed-point conversion (floating-point scatter consumes more resources), and then pay attention to scaling in the intermediate steps to take into account both calculation accuracy and dynamic range. The debugging cycle is long. If the project is large, it may take several days to recompile and generate files for download. The iteration cycle is long and debugging is inconvenient.

[0071] Digital signal processor (DSP) enhances the digital computing unit in the core on the basis of general-purpose processor, increases the number of multipliers, and adds hardware acceleration units for specific algorithms. Compared with general-purpose processors, the digital signal processing capability is greatly enhanced. Currently, DSP mainly uses C language for DSP development, which is relatively convenient. For key processing steps, assembly can be used for optimization. This solution adopts the architecture of FPGA+DSP.

[0072] This solution adopts a DSP-based, FPGA-based architecture. The main functions are described as follows:

[0073] Each DSP has two external DDR4s, totaling 16GB of storage. It is connected to the FPGA using the SRIO X4 interface and mainly performs tasks such as SAR imaging processing and auxiliary data calculation.

[0074] FPGA has a set of DDR externally, which mainly completes functions such as payload data reception, data preprocessing, parameter calculation acceleration, data post-processing and data forwarding, telemetry collection, remote control command analysis and execution, parameter annotation, and watchdog.

[0075] The imaged data is output to the image detection module through the GTX interface. Each module has independent output.

[0076] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0077] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A synthetic aperture radar imaging control device integrating multiple image acquisition modes, characterized in that: include: Integrated digital processing module, SAR antenna; Wherein, the SAR antenna establishes a connection with the integrated radio frequency module, and the SAR antenna establishes a data transmission connection with the integrated digital processing module through the integrated radio frequency module; The SAR antenna target performs microwave imaging and has the ability to output imaging image data and imaging raw analog data. The imaging modes include strip mode, scanning mode and beamforming mode, and image acquisition is performed based on the above multiple imaging modes; The integrated digital processing module completes SAR payload data management, intermediate frequency transmission signal generation, receiving multi-channel data acquisition, timing control function, and beam control function. The integrated digital processing module is a time reference, which is used to ensure the synchronization of the system's receiving and transmitting work, and at the same time executes the ground remote control and telemetry tasks for the SAR subsystem.

2. The synthetic aperture radar imaging control device integrating multiple image acquisition modes according to claim 1, characterized in that: The strip mode is specifically: the SAR antenna aims at a designated ground strip to perform continuous acquisition.

3. The synthetic aperture radar imaging control device integrating multiple image acquisition modes according to claim 1, characterized in that: The scanning mode is specifically: a mode of achieving large-strip coverage through electronic beam control, and using multiple sub-bands to increase imaging width within the coverage range.

4. The synthetic aperture radar imaging control device integrating multiple image acquisition modes according to claim 1, characterized in that: The beamforming mode is specifically: by controlling the SAR antenna azimuth direction antenna beam pointing, it continuously illuminates the target area to obtain a longer synthetic aperture time, and obtain a high-resolution image in a small area that cannot be achieved by ordinary strip mode.

5. The synthetic aperture radar imaging control device integrating multiple image acquisition modes according to claim 4, characterized in that: During the entire synthetic aperture time, the radar antenna continuously adjusts its direction to always illuminate the same area on the ground.

6. The synthetic aperture radar imaging control device integrating multiple image acquisition modes according to claim 1, characterized in that: The SAR antenna also has: Capability of continuous imaging of multiple point targets in a region; Two-dimensional scanning capability, capable of acquiring SAR images with 0.5m spatial resolution and high signal-to-noise ratio in staring spotlight mode; 2-channel transceiver in azimuth and single-channel transceiver in elevation; In-load calibration system; Large angle beam scanning capability; Transmitted signal power amplification and radiation function; Echo signal receiving and low noise amplification functions; Self-safety protection functions such as over duty cycle, over pulse width, over current, short circuit, etc. Raw radar echo data on-board real-time imaging, target detection, target slice extraction and other processing functions; Software note update function; Telemetry data collection and upload function.

7. The synthetic aperture radar imaging control device integrating multiple image acquisition modes according to claim 1, characterized in that: The integrated radio frequency module includes a clock / transmitting module, a receiving module, and an internal calibration module. The transmitting and receiving networks of the SAR antenna are connected to the receiving module, the calibration network of the SAR antenna is connected to the internal calibration module, and the clock / transmitting module, the receiving module, and the internal calibration module are connected to each other.

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