Satellite-borne mechanical scanning and phase scanning combined wide-area radar system

Abstract

The invention discloses a wide-area radar system combining satellite-borne mechanical scanning and phase scanning. The wide-area radar system is composed of a central processing unit, a servo controller, an active phased-array antenna and a scanning mechanism. The servo controller is mounted on the platform cabin, is rigidly connected and does not rotate; the central processing unit and the active phased-array antenna are installed on the load cabin, the load cabin is connected with the platform cabin through the scanning mechanism, and the servo controller controls the whole load cabin to rotate around the center of the load cabin. According to the method, a brand new satellite-borne wide-area radar system architecture is constructed, mechanical scanning and electric scanning characteristics are combined, flexible control of beam broadening, tracking staring, wide-area searching, frequency agility, power control and the like of a radar system is supported, and the method has an application mode integrating detection, tracking, imaging and recognition.

Description

Technical Field

[0001] This invention belongs to the field of radar system design and relates to a wide-area radar system that combines spaceborne mechanical scanning and phase scanning. Background Technology

[0002] Currently operating spaceborne Synthetic Aperture Radar (SAR), as a high-resolution microwave imaging radar capable of operating in all weather conditions and around the clock, has received increasing attention from various countries since the 1950s, and SAR technology has made significant progress. With the expansion of application areas, in addition to the classic strip mode, new modes such as spotlight mode and scanning mode have emerged. Spotlight mode offers high azimuth resolution but a small imaging area and cannot perform continuous observations; scanning mode increases the observation bandwidth through range scanning to achieve large-area observations, however, under the conditions of high-speed spaceborne platforms, the actual observation efficiency remains low. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this invention provides a wide-area radar system that combines spaceborne mechanical scanning and phase scanning, solving the technical bottleneck of limited imaging area and long repeated observation cycle of existing SAR satellites. By combining the characteristics of beam mechanical scanning and phase scanning, it can achieve wide-area target detection on the sea surface.

[0004] To solve the above problems, the technical solution adopted by the present invention includes: A wide-area radar system combining spaceborne mechanical scanning and phase scanning consists of a central processing unit, a servo controller, an active phased array antenna, and a scanning mechanism. The servo controller is mounted on the platform housing and is rigidly connected and does not rotate. The central processing unit and active phased array antenna are mounted on the payload compartment. The payload compartment is connected to the platform compartment through a scanning mechanism. The servo controller controls the entire payload compartment to rotate around its center.

[0005] Optionally, the servo controller receives bus commands to control the rotation and positioning of the scanning mechanism, thereby achieving speed adjustment.

[0006] Optionally, the scanning mechanism consists of a torque motor, an angle encoder, a conductive slip ring, and bearings; A torque motor provides driving torque; an angle encoder detects the angular position and angular velocity of the rotating shaft in real time; a conductive slip ring transmits power, signals, or data between the rotating and stationary parts; and a bearing supports the rotating shaft.

[0007] Optionally, the servo controller control commands drive a torque motor via a conductive slip ring. The torque motor drives the load chamber to rotate, and the angle encoder detects the actual position. The signal is returned to the servo controller via the conductive slip ring, forming a closed-loop servo control circuit.

[0008] Optionally, the central processing unit consists of a power distribution unit module, a control unit module, a frequency integration module, a transceiver channel module, a signal processing module, and a beam control module; The power distribution unit module receives the primary power input from the satellite power supply and transfers it to other sub-units; The control unit module receives bus commands and broadcasts from the satellite, returns real-time status telemetry information, controls other sub-units, and supports a universal satellite bus interface; The frequency synthesis module uses a high-stability crystal oscillator to generate multiple clock sources, providing local oscillator signals for the signal processing module and the transceiver channel module; The radio frequency transceiver module realizes up-conversion and down-conversion of intermediate frequency signals and internal calibration; The signal processing module generates the timing pulses, control signals, and radio frequency transmission signals required by each relevant sub-unit in each working mode; The beam control module quantizes the angle data into control codes for the phase shifter and attenuator based on the operating mode pointing angle, thereby realizing the pointing control of the phased array antenna.

[0009] Optionally, the signal processing module adopts an FPGA + DSP circuit architecture; The FPGA generates timing pulses and control signals for the XC7VX690T and performs preprocessing simultaneously; the external NorFlash chips JFM29GL256RH and JS28F512P30TF are used to store the beam control code and radar waveform of the phased array antenna. The DSP is a TMS320C6678 for post-processing; the DSP chip is connected to an external LSFO512M16VS8SP1 Flash chip for configuration data and algorithm parameters; Two DDR3 chips are each connected externally to the FPGA and DSP chips for real-time computing. The external clock signal is converted into three clocks by the clock chip: the 400MHz sampling clock of the ADC chip ADC12D1600, the 1200Hz sampling clock of the DAC chip EV12DS130, and the 75MHz operating clock of the AD9516 are all fed back to the FPGA. The input is converted into a single-ended signal by the interface chip 26C32 and sent to the FPGA IO pins to transmit internal remote control and telemetry, PPS second-speed, and servo angle signals respectively. At the same time, the FPGA outputs multiple control signals, which are converted into differential signals by the 26C31 to control the microwave channel gain control and transmit the phased array antenna beam control code.

[0010] Optionally, a refresh control chip connected to the FPGA is also included. The refresh control chip is Fudan Micro JFMRS01RH, which can periodically detect the SEFI status and refresh the FPGA, while also supporting code refactoring and program loading. The FPGA, DSP, and refresh control chip are equipped with 100MHz, 100MHz, and 10MHz crystal oscillators, respectively.

[0011] Optionally, the active phased array antenna consists of a locking and releasing device, a deployment drive mechanism, a waveguide slot array, a T / R assembly, a secondary power supply, a delay assembly, a power distribution network, and a wave controller. During launch, it is retracted by a locking and releasing device, and after entering orbit, it is deployed by a deployment drive mechanism. The waveguide slot array is an antenna radiating element, which realizes electromagnetic wave radiation by opening slots in the metal waveguide wall; The T / R module amplifies the signal during transmission and uses low-noise amplification and phase-shift / attenuation control during reception to achieve beamforming. The secondary power supply converts the primary bus voltage to multiple low voltages required by the T / R components and provides isolation, voltage regulation, and overcurrent protection. Delay components compensate for beam pointing offset at different frequencies in broadband phased arrays; The power distribution network distributes the radio frequency signal from the common port to each T / R component or combines the signals from each channel; The beam controller calculates the required phase shift, attenuation, and / or delay for each channel according to the task instructions, and sends control codes to the T / R component or delay component.

[0012] The advantages of this invention are: This invention presents a spaceborne wide-area search radar system combining mechanical and electronic scanning. A servo motor drives the planar phased-array antenna to rotate, achieving beam scanning. Mechanical scanning is used in the azimuth direction to achieve beam rotation, sector scanning, and point positioning, while phased-array phase-shifting electronic scanning is used in the elevation direction to achieve beam switching. This invention constructs a novel spaceborne wide-area radar system architecture, combining the characteristics of mechanical and electronic scanning. It supports flexible control of the radar system to meet requirements such as beam widening, tracking staring, wide-area search, frequency agility, and power control, and features an integrated application mode for detection, tracking, imaging, and identification. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 A schematic diagram of a ring-scan radar in operation (top view); Figure 2 This is a block diagram of the radar system in an embodiment of the present invention; Figure 3 This is a block diagram of an active phased array in an embodiment of the present invention; Figure 4 This is a block diagram of the signal processing function in an embodiment of the present invention. Detailed Implementation

[0014] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0015] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0016] Figure 1 This is a schematic diagram (top view) of a ring-scan radar system. The radar system of this invention, mounted on a spaceborne platform, enables rapid wide-area observation. It employs mechanical scanning in the azimuth direction and electronic scanning in the elevation direction, with beam illumination forming a wide-area ring-shaped imaging region. This achieves wide-area target detection and reliable detection on the sea surface, while also providing a short revisit period and high temporal resolution, allowing for timely information acquisition. Furthermore, through flexible time slot allocation and rapid beam switching, it offers an integrated application mode for detection, tracking, imaging, and identification.

[0017] Combination Figure 2 This invention relates to a wide-area radar system combining spaceborne mechanical scanning and phase scanning, enabling wide-area sea surface target search and reliability detection, and adapting to the payload envelope and weight requirements of microsatellite platforms. It consists of four parts: a central processing unit, a servo controller, an active phased array antenna, and a scanning mechanism. The servo controller is rigidly connected to the platform cabin and does not rotate. The central processing unit and the active phased array antenna are mounted on the payload cabin, which is connected to the platform cabin via the scanning mechanism. The servo controller controls the entire payload cabin to rotate around its center, achieving beam circular scanning, sector scanning, and pinpointing functions.

[0018] The servo controller receives bus commands and controls the scanning mechanism's rotation and positioning functions according to the working mode. It can also achieve speed adjustment and is implemented using a low-power, lightweight MCU.

[0019] The scanning mechanism mainly consists of a torque motor, an angle encoder, a slip ring, and bearings. The torque motor primarily provides the driving torque; the angle encoder mainly measures the angles of the mechanism; the slip ring serves as a channel for transmitting signals and power between the stator and rotating components; the angle encoder detects the angular position and angular velocity of the rotating shaft in real time, providing high-precision feedback signals; the slip ring transmits power, signals, or data (such as power supply, encoder signals, control commands, etc.) between the rotating and stationary components; and the bearings support the rotating shaft, reducing friction and ensuring smooth rotation. The servo controller's control commands drive the torque motor through the slip ring, which in turn drives the load chamber to rotate. The angle encoder detects the actual position, and the signal is returned to the servo controller via the slip ring, forming a closed-loop servo control circuit.

[0020] The central processing unit (CPU) is the core radar equipment, consisting of a power distribution unit, a control unit (lower-level machine), a frequency synthesizer, an RF transceiver channel, a signal processing unit, and a beam control module. The power distribution unit receives primary power from the satellite and distributes it to other sub-units. The control unit receives bus commands and broadcasts from the satellite, returns real-time status telemetry information, and controls other sub-units, supporting common satellite bus interfaces such as 1553B and CAN. The frequency synthesizer uses a high-stability crystal oscillator to generate multiple clock sources, providing local oscillator signals for the signal processing unit and the up- and down-conversion of the transceiver channel. The RF transceiver channel performs up- and down-conversion and internal calibration of the intermediate frequency signal. Signal processing generates timing pulses, control signals, and RF transmission signals required by each relevant sub-unit in each operating mode. Beam control quantizes the pointing angle data into control codes for the phase shifter and attenuator based on the pointing angle of the operating mode, achieving pointing control of the phased array antenna.

[0021] The phased array antenna is a deployable planar two-dimensional scanning solid-state active phased array antenna with pulse operation. It can amplify the power of the transmitted signal and radiate electromagnetic energy into a designated airspace, and complete the echo signal reception and low-noise amplification. It has two-dimensional beam scanning capability. It consists of components such as a locking and releasing device, a deployment drive mechanism, waveguide slot array, TR module, secondary power supply, delay module, power distribution network, and wave controller. To save space in the rocket fairing, the radar antenna is retracted by a locking and releasing device during launch and deployed by a deployment drive mechanism after entering orbit. The waveguide slot array is the antenna radiating element, which radiates electromagnetic waves by opening slots in the metal waveguide wall. The T / R module amplifies the signal during transmission and performs low-noise amplification and phase shift / attenuation control during reception to achieve beamforming. The secondary power supply converts the primary bus voltage (e.g., 28V / 100V) into multiple low voltages (e.g., ±5V, 3.3V, 12V, etc.) required by the T / R module and provides isolation, voltage regulation, and overcurrent protection. The delay module compensates for beam pointing offset at different frequencies in the broadband phased array to achieve true time delay rather than just phase shift. The power distribution network distributes the radio frequency signal from the common port to each T / R channel (transmit) or combines the signals from each channel (receive), usually using microstrip, stripline, or waveguide structures. The wave controller calculates the required phase shift / attenuation / delay for each channel according to the mission instructions and sends control codes to the T / R module or delay unit.

[0022] In one embodiment of the present invention, considering cost, weight and power consumption, the active phased array antenna performs phased array scanning in the elevation dimension, with low grating lobe scanning at a unit spacing of 0.77 wavelengths in the elevation direction, resulting in a lightweight antenna design. In the azimuth direction, the unit spacing is 9 wavelengths with low grating lobe scanning, effectively suppressing grating lobe effects and effectively reducing the radar false alarm rate.

[0023] In one embodiment of the present invention, a T / R component-fed waveguide antenna achieves the requirements of low profile and lightweight design. It employs contact-type flexible insertion feeding technology to enable rapid assembly and signal transmission between the T / R component and the feeding network / backplane. The detachable, highly reliable electrical connection scheme solves the current problem of accurate waveguide antenna probe feeding control. The wavecontrol system receives data, clock, and enable signals from the radar data processor, splits them into multiple outputs, and simultaneously completes the telemetry acquisition and transmission of typical location temperature and power.

[0024] In one embodiment of the present invention, the phased array antenna deployment and locking mechanism locks the two sub-plates on both wings. Before launch, the antenna is in a retracted state to ensure that the maximum envelope meets the carrying requirements. After entering orbit, the antenna is deployed along the azimuth direction to the two wing sub-plates.

[0025] In one embodiment of the present invention, the internal calibration network integrated in the transceiver channel includes transmit power calibration, receive gain calibration, and reference signal calibration, which can monitor the status of each TR module of the phased array antenna in orbit.

[0026] In one embodiment of the present invention, the upconversion module of the transceiver channel includes a cavity filter and an upconversion channel, which is used to filter the analog intermediate frequency signal generated by the central processing unit through the cavity filter, perform two upconversions to convert it into a radio frequency signal and output it to the internal calibrator, which then sends it to the active phased array antenna to be transmitted as a radiated signal.

[0027] In one embodiment of the present invention, the downconversion module of the transceiver channel is used to mix, filter, and amplify the signal received by the slot antenna with the local oscillator and the second local oscillator signals generated by the local oscillator and reference generation module, respectively, to obtain an intermediate frequency signal, which is then output to the signal processing unit for digital acquisition.

[0028] In one embodiment of the present invention, the signal processing unit of the central processing unit simultaneously receives the intermediate frequency analog echo signal from the down-converted transceiver channel, and performs AD sampling, digital down-conversion, digital beamforming, pulse compression, coherent accumulation, non-coherent accumulation, range CFAR, range-velocity CFAR, clutter map processing, range tracking, angular error calculation and other processing on the intermediate frequency analog echo signal to form track information. Example 1: The spaceborne wide-area detection radar consists of four parts: an active phased array antenna, a central processing unit, a scanning mechanism, and a servo controller. Figure 2 As shown.

[0029] 1. Active phased array antenna It consists of a locking and releasing device, a deployment drive mechanism, waveguide slot array, TR assembly, secondary power supply, delay assembly, power distribution network, and wave controller components, such as... Figure 3 As shown, it is used for amplification of radio frequency signals, low-noise amplification of space scanning radiation, and radar echoes. It has low sidelobe beamforming capability and power management capability. However, due to the size of the rocket fairing (generally ≤5 meters in diameter), a deployable / foldable structure must be adopted. The planar phased array consists of multiple sub-plates. Before launch, the antenna is in a retracted state to ensure that the maximum envelope meets the launch requirements. After entering orbit, it unfolds along the azimuth towards the two long side sub-plates. Figure 3 In this system, the radar phased array antenna is the core, consisting of multiple sub-boards along the azimuth direction. Each sub-board is an electromechanical-thermal integrated multifunctional microsystem. Each sub-board contains several TR components, slotted arrays, TR components, secondary power supplies, delay components, a power divider network, and a beam controller. The transmit and receive signals between sub-boards are converted into sum and difference signals through a sum-difference network, and the calibration signals between sub-boards are combined by a power divider to form the calibration signal for the entire antenna. The power supply bus is divided into multiple branches to supply power to the sub-board power modules, and the processor acts as the main beam controller, transmitting waveform control codes to each sub-board.

[0030] In transmit mode, the transmit link amplifies the power of the input linear frequency modulated signal and radiates horizontally or vertically polarized electromagnetic energy into a designated airspace. In receive mode, the antenna array receives the horizontally or vertically polarized echo signal, which is then sent to the central processing unit (CPU) after passing through a low-noise amplification link. To enable antenna performance monitoring, fault detection, and isolation, the antenna has an independent calibration network that, under the control of the CPU, can calibrate the transmit and receive links.

[0031] 2. Central Processing Unit The central processing unit is the core equipment of the radar, consisting of a power distribution unit, a control unit (lower-level machine), a frequency synthesis unit, a radio frequency transceiver channel, a signal processing unit, and a beam control module.

[0032] The power distribution unit receives the primary power input of +42V from the satellite power supply and transfers it to the secondary power required by other sub-units, namely +12V, +5V, and -5V. The control unit receives bus commands and broadcasts from the satellite, returns real-time status telemetry information, controls other sub-units, supports common satellite bus interfaces such as 1553B and CAN, and uses a low-power MCU processor.

[0033] Frequency synthesis uses a high-stability crystal oscillator to generate multiple clock sources, providing local oscillator signals for the up-conversion and down-conversion of the signal processing unit and the transceiver channel. For example, LO1 is the reference clock for the signal processing unit and provides the sampling clock for the ADC and DAC. LO2 and LO3 are the local oscillator signals for up-conversion and down-conversion, respectively.

[0034] The radio frequency transceiver channel is responsible for up-conversion, down-conversion, and internal calibration of intermediate frequency (IF) signals. For example, the zero IF signal generated by the DAC is mixed to the X band by the up-conversion module, filtered, amplified, and then sent to the phased array antenna. The phased array antenna receives the echo signal, amplifies and filters it, and then mixes it to zero IF by the down-conversion module. After being acquired by the DAC, it is processed by the back-end.

[0035] Signal processing generates the timing pulses, control signals, and intermediate frequency (IF) transmit signals required by each relevant sub-unit in each operating mode. Simultaneously, it receives IF analog echo signals from the down-converted IF channel, performs AD sampling, digital down-conversion, digital beamforming, pulse compression, coherent accumulation, non-coherent accumulation, range CFAR, range-velocity CFAR, clutter map processing, range tracking, and angular error calculation on the IF analog echo signals to form track information. The hardware adopts an FPGA + DSP circuit architecture, such as... Figure 4As shown. The EV12DS130 generates a linear frequency modulated signal, the ADC12D1600 is used for signal acquisition, and the core component, the FPGA (XC7VX690T), generates timing pulses and control signals while simultaneously performing preprocessing, including digital down-conversion, digital beamforming, pulse compression, coherent accumulation, non-coherent accumulation, range CFAR, range-velocity CFAR, and clutter map processing. The DSP (TMS320C6678) performs post-processing, including range tracking, angular error calculation, and track correlation. An external 1.6GHz clock signal is converted into three clocks by a clock chip: a 400MHz sampling clock from the ADC12D1600, a 1200Hz sampling clock from the EV12DS130, and a 75MHz operating clock from the AD9516. External Nor Flash chips JFM29GL256RH and JS28F512P30TF are used to store the phased array antenna beam control codes and radar waveforms. To improve the FPGA's resistance to single-event accumulation effects, the refresh control chip is Fudan Microelectronics JFMRS01RH, which can periodically detect SEFI status and refresh the FPGA, while also supporting code refactoring and program loading. An external LSFO512M16VS8SP1 Flash chip is used for configuration data and algorithm parameters on the DSP chip. Two external DDR3 (W3J512M32GT) chips are connected to both the FPGA and DSP chips for real-time computing, with a storage capacity of 2GB per chip.

[0036] The three differential 422 inputs are converted into single-ended signals by the interface chip 26C32 and sent to the FPGA IO pins to transmit internal remote control and telemetry, PPS second-speed, and servo angle signals, respectively. At the same time, the FPGA outputs multiple control signals, which are converted into differential signals by the 26C31 to control microwave channel gain control (MGC) and transmit phased array antenna beam control codes.

[0037] The FPGA, DSP, and refresh control chip are configured with 100MHz, 100MHz, and 10MHz crystal oscillators, respectively, using internal operating references.

[0038] Beam control is based on the pointing angle of the working mode. The angle data is quantized into control codes for the phase shifter and attenuator to achieve pointing control of the phased array antenna. On the hardware side, the BQR2V3000 chip of the 772 Institute is used for beam control code distribution of the phased array antenna.

[0039] 3. Scanning mechanism The scanning mechanism mainly consists of a torque motor, an angle encoder, a conductive slip ring, and bearings. The torque motor primarily provides the driving torque for the mechanism; the angle encoder is mainly used to measure the angles of the mechanism; the conductive slip ring serves as a channel for transmitting signals and power between the stator and rotating components; the bearings consist of a pair of angular contact bearing assemblies and deep groove ball bearings, primarily used for supporting the shaft system of the scanning mechanism.

[0040] 4. Servo Controller The equipment installed on the satellite platform cabin controls the antenna to rotate at a specified speed according to bus commands, thus performing scanning. It can also adjust the rotation speed or stop at any specified angle and hold it. The internal serial port provides angle information to the central processing unit.

[0041] The servo controller adopts dual-loop control of position loop and current loop. It uses photoelectric encoder to detect the current azimuth angle value, and at the same time, ADC collects three-phase full-bridge drive current. FPGA implements PID control compensation algorithm, generates pulse width modulation signal, converts and amplifies power to drive the motor in the turntable, and realizes high-precision and high-dynamic motion control of motor.

[0042] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A space-borne mechanically scanning and phase scanning combined wide-area radar system, characterized in that, The central processor, the servo controller, the active phased array antenna and the scanning mechanism are composed; The servo controller is installed on the platform cabin and is rigidly connected and not rotated; The central processor and the active phased array antenna are installed on the load cabin, the load cabin is connected with the platform cabin through the scanning mechanism, and the servo controller controls the rotation of the whole load cabin around the center.

2. The space-borne mechanically scanned and phase scanned combined wide-area radar system of claim 1, wherein, The servo controller receives bus instructions, controls the rotation and positioning of the scanning mechanism, and realizes speed regulation.

3. The space-borne mechanically scanned and phase scanned combined wide-area radar system according to claim 1 or 2, characterized in that, The scanning mechanism is composed of a torque motor, an angle encoder, a conductive slip ring and a bearing; The torque motor provides a driving torque; the angle encoder detects the angular position and angular velocity of the rotating shaft in real time; the conductive slip ring transmits power, signals or data between rotating parts and stationary parts; and the bearing supports the rotating shaft.

4. The space-borne mechanically scanned and phase scanned combined wide-area radar system of claim 3, wherein, The servo controller controls instructions to drive the torque motor through the conductive slip ring, the torque motor drives the load cabin to rotate, the angle encoder detects the actual position, and the signal is returned to the servo controller through the conductive slip ring; a closed-loop servo control loop is formed.

5. The space-borne mechanically scanned and phase scanned combined wide-area radar system according to claim 1 or 2, characterized in that, The central processor is composed of a power distribution unit module, a control unit module, a frequency synthesis module, a transceiver channel module, a signal processing module and a beam control module; The power distribution unit module is a primary power supply receiving satellite power input and transferring it to other extensions; The control unit module receives bus instructions and broadcasts input by the satellite, returns real-time state telemetry information, controls other extensions and supports a general satellite bus interface; The frequency synthesis module generates multiple clock sources by using a high-stability crystal oscillator to provide local oscillator signals for the signal processing module and the transceiver channel module; The radio frequency transceiver module realizes up-conversion and down-conversion of intermediate frequency signals and internal calibration; The signal processing module generates timing pulses, control signals and radio frequency transmission signals required by each relevant extension in each working mode; The beam control module quantizes angle data into control codes of phase shifters and attenuators according to the pointing angle of the working mode, so as to realize the pointing control of the phased array antenna.

6. The space-borne mechanically scanned and phase scanned combined wide-area radar system of claim 5, wherein, The signal processing module adopts an FPGA+DSP circuit architecture; The FPGA XC7VX690T generates timing pulses, control signals and completes preprocessing; the Nor Flash chips JFM29GL256RH and JS28F512P30TF externally connected to the FPGA are used for storing beam control codes of the phased array antenna and radar waveforms; The DSP TMS320C6678 completes post-processing; the Flash chip LSFO512M16VS8SP1 externally connected to the DPS chip is used for configuring data and algorithm parameters; Two pieces of DDR3 externally connected to the FPGA and the DSP chip are used for real-time calculation; An external clock signal is converted into three clock signals by a clock chip, and the 400MHz sampling clock of the ADC chip ADC12D1600, the 1200Hz sampling clock of the DAC chip EV12DS130 and the working clock of the AD9516 are all fed back to the FPGA. The interface chip 26C32 converts the input signals into single-ended signals and transmits the internal remote control and telemetry signals, PPS second pulse signals and servo angle signals to the FPGA IO pins. Meanwhile, the FPGA outputs multi-channel control signals which are converted into differential signals by 26C31 to control the microwave channel gain and the phased array antenna beam control code.

7. The space-borne mechanical scan and phased array combined wide-area radar system of claim 6, wherein, A refresh control chip connected with the FPGA is also provided. The chip JFMRS01RH from Fudan Micro is selected for the refresh control, which can detect the SEFI state and refresh the FPGA at a regular time, and support code reconstruction and program loading. The FPGA, DSP and refresh control chip are respectively configured with 100MHz, 100MHz and 10MHz crystal oscillators.

8. The space-borne mechanically scanned and phase scanned combined wide-area radar system according to claim 1 or 2, characterized in that, The active phased array antenna is composed of locking release devices, deployment driving mechanisms, waveguide slot arrays, T / R components, secondary power supplies, delay components, feed power division networks and wave control machines. The locking release devices are used to fold the antenna during launching, and the deployment driving mechanisms are used to unfold the antenna after entering the orbit. The waveguide slot array is the antenna radiation unit, which realizes electromagnetic wave radiation by opening slots on the metal waveguide wall. The T / R component amplifies the signal during transmission, and realizes beamforming by low-noise amplification and phase shift / attenuation control during reception. The secondary power supply converts the primary bus voltage into multiple low voltages required by the T / R component, and provides isolation, voltage stabilization and overcurrent protection. The delay component compensates for the beam pointing deviation at different frequencies in the wideband phased array. The feed power division network distributes the radio frequency signals from the common port to each T / R component or combines the signals of each channel. The wave control machine calculates the required phase shift, attenuation and / or delay amount of each channel according to the task instructions, and sends the control code to the T / R component or the delay component.

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