A buffered portable target detection radar system package

Abstract

The application discloses a kind of buffering portable target detection radar system package in the field of radar technology: including: middle frame support;Buffer side plate, the buffer side plate is symmetrically arranged on the left and right two side walls of the middle frame support, the buffer side plate includes the installation side plate assembly arranged on the side wall of the middle frame support, the shock-absorbing spring evenly arranged in the side groove of the installation side plate assembly and the arc plate arranged in the side groove of the installation side plate assembly and contacted with the shock-absorbing spring, it also includes the first buffer rubber pad symmetrically arranged on the upper and lower two side walls of the middle frame support, it also includes the second buffer rubber pad symmetrically arranged on the front and rear two side walls of the middle frame support, the application is buffered and shock-absorbed to the middle frame support by buffer side plate, when receiving external force impact, electrical elements installed in the middle frame support can be effectively protected, and service life is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of radar technology, specifically to a buffered portable target detection radar system package. Background Technology

[0002] Moving target reconnaissance radar is used to detect moving targets on land and water and determine their coordinates. It has a strong ability to distinguish moving targets and accurately determine their coordinates.

[0003] Existing portable target detection radar systems are easy to carry and meet the requirements of portable random detection and long-term stable use. However, the application scenarios of existing portable target detection radar systems are relatively complex. They can be used in places with high traffic such as airports. Inevitably, there is a risk of dropping during use. The impact force generated when the radar comes into contact with the ground during a drop will inevitably damage the electrical components inside the radar, seriously affecting the service life of the radar. Summary of the Invention

[0004] The purpose of this invention is to provide a buffered portable target detection radar system package to solve the problem mentioned in the background art that the existing portable target detection radar systems have complex usage scenarios. They can be used in places with high traffic such as airports, but there is an unavoidable risk of them being dropped during use. The impact force generated when the radar comes into contact with the ground during the drop will inevitably damage the electrical components inside the radar, seriously affecting the service life of the radar.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a buffered portable target detection radar system package comprising:

[0006] Mid-frame bracket;

[0007] Buffer side plates are symmetrically arranged on the left and right side walls of the middle frame bracket.

[0008] Preferably, it also includes first buffer rubber pads symmetrically disposed on the upper and lower side walls of the middle frame bracket.

[0009] Preferably, it also includes second buffer rubber pads symmetrically disposed on the front and rear side walls of the middle frame bracket.

[0010] Preferably, the buffer side plate includes a mounting side plate assembly disposed on the side wall of the middle frame bracket, a shock-absorbing spring uniformly disposed in the side groove of the mounting side plate assembly, and an arc-shaped plate disposed in the side groove of the mounting side plate assembly and in contact with the shock-absorbing spring.

[0011] Preferably, the mounting side plate assembly includes a mounting side plate disposed on the side wall of the middle frame bracket and a mounting groove formed on the mounting side plate on the side away from the middle frame bracket.

[0012] Preferably, the damping spring includes a first damper disposed on the side wall of the mounting groove cavity near the middle frame bracket, a spring disposed on the first damper on the side away from the middle frame bracket, a second damper disposed on the spring on the side away from the first damper and connected to the plane side of the arc plate, and a damping ball disposed on the inner side of the spring along the spiral trajectory of the spring.

[0013] Preferably, an ultrasonic generator is installed in the inner cavity of the middle frame support.

[0014] Preferably, an ultrasonic transducer is mounted on the side of the arc plate facing the middle frame support, and the ultrasonic transducer is electrically connected to the ultrasonic generator.

[0015] Preferably, a vibration sensor is also installed on the arc-shaped plate.

[0016] Compared with the prior art, the beneficial effects of the present invention are: the buffered portable target detection radar system package uses buffer side plates to buffer and dampen the mid-frame support, which can effectively protect the electrical components installed inside the mid-frame support when subjected to external impact, thus ensuring service life. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the buffer side plate structure of the present invention;

[0019] Figure 3 This is a schematic diagram of the side plate assembly structure of the present invention;

[0020] Figure 4 This is a schematic diagram of the shock-absorbing spring structure of the present invention.

[0021] In the diagram: 100 middle frame bracket, 200 first buffer rubber pad, 300 second buffer rubber pad, 400 buffer side plate, 410 mounting side plate assembly, 411 mounting side plate, 412 mounting groove, 420 shock absorber spring, 421 first damper, 422 spring, 423 second damper, 424 shock absorber ball, 430 curved plate. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a buffered portable target detection radar system package. The buffered side plates cushion and dampen the mid-frame support, effectively protecting the electrical components installed inside the mid-frame support when subjected to external impacts, thus ensuring its service life. Please refer to [link / reference]. Figure 1 It includes: a middle frame bracket 100, a first buffer rubber pad 200, a second buffer rubber pad 300, and a buffer side plate 400;

[0024] Please see Figure 1-4It also includes first buffer rubber pads 200 symmetrically disposed on the upper and lower side walls of the middle frame bracket 100, and second buffer rubber pads 300 symmetrically disposed on the front and rear side walls of the middle frame bracket 100. Buffer side plates 400 are symmetrically disposed on the left and right side walls of the middle frame bracket 100. The buffer side plates 400 include a mounting side plate assembly 410 disposed on the side wall of the middle frame bracket 100, shock-absorbing springs 420 evenly disposed in the side grooves of the mounting side plate assembly 410, and shock-absorbing springs 420 disposed in the side grooves of the mounting side plate assembly 410 and... The arc-shaped plate 430 in contact with the damping spring 420, the mounting side plate assembly 410 includes a mounting side plate 411 disposed on the side wall of the middle frame bracket 100 and a mounting groove 412 formed on the mounting side plate 411 on the side away from the middle frame bracket 100, the damping spring 420 includes a first damper 421 disposed on the side wall of the mounting groove 412 near the middle frame bracket 100, a spring 422 disposed on the first damper 421 on the side away from the middle frame bracket 100, and a spring 422 disposed on the spring 422 on the side away from the first damper 421 and in contact with the arc-shaped plate 430, the mounting side plate assembly 410 including a mounting side plate 411 disposed on the side wall of the mounting groove 412 near the middle frame bracket 100, and a mounting groove 412 formed on the side wall of the spring 42 ... near the first damper 421 and in contact with the arc-shaped plate 430, the mounting side plate assembly 410 including a mounting side plate 411 disposed on the side wall of the middle frame bracket 100 and the mounting groove 412 formed on the side wall of the mounting groove 412 near the middle frame bracket 100. The second damper 423 connected to one side of the curved plate 430 and the shock-absorbing ball 424 set inside the spring 422 along the spiral trajectory of the spring 422, damp the narrow side of the middle frame bracket through the first and second buffer rubber pads. After the middle frame bracket falls, it can effectively protect the narrow side of the middle frame bracket. The buffer side plate protects the wide side of the middle frame bracket. After the middle frame bracket falls, the impact force generated by the curved plate contacting the ground is transmitted to the shock-absorbing spring. The first and second dampers on the shock-absorbing spring dampen the impact. The spring achieves the purpose of buffering. The shock-absorbing ball set inside the spring along the spiral trajectory can support the spring when the spring deforms, which can further achieve the purpose of buffering and vibration reduction. The shock-absorbing ball is made of damping material. The shock-absorbing spring achieves the purpose of buffering and vibration reduction of the curved plate, avoiding the impact force from being transmitted to the inside of the middle frame bracket and causing damage to the electrical components installed inside the middle frame bracket. It effectively protects the electrical components installed inside the middle frame bracket and improves the service life of the radar.

[0025] Please see Figure 1-4 An ultrasonic generator is installed in the inner cavity of the middle frame support 100. An ultrasonic transducer is installed on the side of the arc plate 430 facing the middle frame support 100. The ultrasonic transducer is electrically connected to the ultrasonic generator. A vibration sensor is also installed on the arc plate 430. A microcomputer is also installed in the inner cavity of the middle frame support. When the middle frame support is dropped, the vibration sensor detects the impact force value and transmits the value to the microcomputer. The microcomputer controls the ultrasonic generator to generate ultrasonic waves corresponding to the impact force value. The ultrasonic waves are emitted through the ultrasonic transducer. The ultrasonic waves are transmitted through the arc plate and cancel each other out with the impact force, thereby achieving the purpose of buffering and shock absorption.

[0026] The internal cavity of the 100 contains an antenna, microwave, digital processing, power supply, and terminal control.

[0027] The target detection radar uses a microstrip array one-dimensional phase-scanning antenna, with the antenna array consisting of 40 subarrays, each containing 16 radiating elements. It employs diode phase shifters and a microstrip power divider combining network to realize a lightweight and compact electronically scanned array antenna. It uses active reception, energy management, long-term coherent accumulation, and random scanning technologies to improve the radar's anti-detection capability. It uses Magic T to form sum and difference beams and improves azimuth resolution through digital beam compression.

[0028] During radar detection and transmission, the radio frequency signal output by the transmitter is distributed to the TR module via a circulator and a 40-channel power divider. The TR module radiates electromagnetic energy into the designated space through the radar antenna, forming a total transmit beam in space. During reception, the echo signal passes through the TR module and a power combining network to generate sum and difference echo signals. The sum and difference signals are then mixed by a circulator and a mixer, amplified by an intermediate frequency, and sent to a signal processor for target detection.

[0029] The intermediate frequency echo signal is sampled by an A / D converter and processed by digital down-conversion (DDC) to zero intermediate frequency for digital pulse compression. MTD processing with corresponding number of points is then performed on both the sum and difference beams. After target detection processing, the sum beam signal yields the target's range and amplitude information. Then, using the target range and amplitude information detected by the sum and difference beams, beam lobe compression processing is performed on the azimuth plane, followed by amplitude monopulse angle measurement.

[0030] In search mode, the search beam operates in either stepped or random scanning mode. In stepped scanning, the step size is 0.7θB (where θB is the azimuth beamwidth in a sinusoidal coordinate system), and sequential position amplitude-comparison single pulses are used to acquire the target azimuth angle. To reduce beam scanning loss, the pointing angle between two frame scans differs by 0.35θB. In random scanning, while maintaining a relatively constant data rate for each position, search positions are randomly assigned, and amplitude-comparison single pulses are used to acquire the target azimuth angle.

[0031] The target detection radar operates on a pulse-wave rhythm, with the number of pulses, pulse repetition frequency, pulse width, and signal type of each pulse-wave adaptively controlled by the control unit according to the operating mode. The control unit receives control commands from the terminal control unit and performs orderly control of the antenna, microwave, and digital processing systems, ensuring coordinated operation of all systems.

[0032] The terminal control unit is the only human-machine interface of the target detection radar. All control commands are sent by the radar operator to the far end (antenna transceiver unit) or near end (terminal control unit) through the terminal control unit.

[0033] The target detection radar's detection mission is mainly divided into the following stages:

[0034] System self-test and calibration

[0035] After the target detection radar is powered on, it first performs a self-test, which mainly includes checking the operating status of each system, communication links, and cable connections. After the self-test is complete, the location and direction coordinates of the radar installation site are obtained. The radar's operating mode, data rate, data reporting interface, and communication protocol are then set according to the operational mission specifications.

[0036] Conduct detection

[0037] After the radar completes self-testing and calibration, it can be controlled to enter search mode. In this mode, the radar antenna beam electronically scans within a range of ±40° to detect targets in the area.

[0038] The detected battlefield targets can be processed as follows:

[0039] TWS tracking: At a fixed, low data rate, it performs simultaneous search and tracking of the target through trajectory filtering, extrapolation, and other methods.

[0040] TAS Tracking: TAS mode refers to the search and track (TAS) process for relatively high-threat battlefield targets already established. Once the target detection radar detects a battlefield target, the operator can manually switch to TAS mode, and the number of TAS targets in a batch cannot exceed four.

[0041] Target classification and identification: Identification mode refers to the processing of tracked (TAS) tracks or high-threat point targets. Target detection radar primarily uses manual identification for battlefield targets. In identification mode, the wave standing number (VSN) and identification frequency can be adaptively adjusted based on the identification results.

[0042] Audible alarm: An audible alarm can be triggered for battlefield targets in the vicinity of the warning area, and their points and tracks will be displayed in a flashing manner to alert the operator.

[0043] Data processing and intelligence processing

[0044] Target detection radar can output detection, tracking, identification, and alarm information to peripheral devices through a pre-defined communication link.

[0045] To meet the requirements of single-person portability and ensure normal operation of the product in various war environments, the target detection radar is powered by lithium batteries.

[0046] The secondary power supplies for each subsystem in the radar antenna transceiver unit adopt a distributed power supply method. The terminal control unit adopts a separate power supply method.

[0047] The power supply design for each subsystem of the target detection radar is as follows:

[0048] The total power consumption of the antenna transceiver unit is less than 55W, and the total power consumption of the terminal control unit is less than 5W. The power consumption design of each subsystem within the antenna transceiver unit is as follows:

[0049] Antenna subsystem: ≤20W; Microwave subsystem: ≤15W

[0050] Digital processing system: ≤20W; Terminal control subsystem: 5W (separate power supply)

[0051] Based on the above analysis, the total power consumption of the target detection radar in an 8-level wind environment is 60W, which meets the system's power consumption requirements for the radar system.

[0052] The main radar equipment includes: antenna transceiver unit, terminal control unit, and power supply unit;

[0053] The dimensions of the antenna transceiver unit are: 420mm (width) × 220mm (height) × 100mm (thickness).

[0054] The antenna transceiver unit contains all the electrical equipment of the radar except for the terminal control unit, including: antenna system, microwave system, digital processing system and power supply unit.

[0055] The antenna transceiver unit housing consists of three parts: the radome, the frame, and the heat dissipation cover. The radome is made of paper honeycomb and is mounted on the front of the integrated frame. The radome is designed with a curved shape, both for aesthetic purposes and to provide cushioning in case of drops.

[0056] The antenna array is mounted on the front face of the frame. The microwave system and digital processing system are fixed to the rear heat sink cover. The heat-generating components of the microwave system and digital processing system are in close contact with the rear heat sink cover by thermal pads. The wave control board is placed and fixed above the power divider. The power divider and TR assembly are fixedly mounted on the frame.

[0057] The mounting end face at the bottom of the frame is connected to the tripod head, and the connection between the two is a quick-tight thread.

[0058] The entire transceiver enclosure features a sealed design with conductive heat dissipation. This sealed structure ensures the system has excellent environmental adaptability.

[0059] The main frame material is cast magnesium alloy ZM5. The mechanical properties of ZM5, ZL101A, and ABS plastic are compared in the table below.

[0060] Comparison table of material mechanical properties

[0061]

[0062] It can be seen that magnesium alloys have the following three characteristics: (1) The density of magnesium alloys is 67% of that of aluminum, making them the lightest among metallic structural materials; the yield strength of magnesium alloys is roughly equivalent to that of aluminum alloys, and is 4 to 5 times that of non-metals; therefore, under the same strength and stiffness conditions, using magnesium alloys to make structural parts can greatly reduce the weight of the parts. (2) The thermal conductivity of magnesium is comparable to that of cast aluminum alloy ZL101A. (3) Compared with aluminum alloys, magnesium alloys have a lower elastic modulus, and under the same stress conditions, they can consume more deformation energy, have noise reduction and vibration reduction functions, and can withstand greater impact and vibration loads.

[0063] To enhance the corrosion resistance of magnesium alloys, a novel surface treatment method—micro-arc oxidation—is employed for structural components made of magnesium alloys. Structural components treated with micro-arc oxidation exhibit high hardness, good wear resistance, good toughness, and excellent corrosion resistance, high-temperature oxidation resistance, and insulation properties, demonstrating superior performance.

[0064] The enclosure has a power consumption of approximately 55W. To be on the safe side, the structure is designed for 70W. Due to the sealed design, heat dissipation relies solely on conduction, requiring thermal control optimization in the structural layout.

[0065] Thermal analysis of the transceiver enclosure was performed using FLOTHERM software. Simulation results show that the sealed conductive heat dissipation method is feasible.

[0066] The target detection radar weighs 11.55 kg. The specific weight specifications of the radar system are shown in the table below.

[0067] Radar Subsystem Weight Table

[0068]

[0069] The antenna consists of four parts: antenna array, TR components, power distribution network, and beam controller.

[0070] Based on the radar system's technical specifications for the antenna system, the antenna's center operating frequency is designed to be **GHz, its bandwidth to be **MHz, and its aperture to be approximately 400×200mm².

[0071] Under the condition of actual usable aperture (180×380mm2), considering aperture utilization efficiency, feeder loss, amplitude and phase distribution error, the antenna aperture gain is estimated to be 31.0dB.

[0072] The TR assembly consists of four 10-channel TR modules. Each 10-channel TR module comprises a dedicated transceiver chip, an amplitude and phase control chip, a power divider / combiner network, a preamplifier, and a wave controller board. Both the RF input and output interfaces use SMP connectors.

[0073] Wave controller

[0074] The transmit / receive control logic can realize the control functions of one or more 1×10 modules in the transmit, receive, and turn-off states.

[0075] The truth table for the control logic is shown below.

[0076] Control Logic Truth Table

[0077] SWITCH R / EN T / EN PWR_5V_R PWR_5V_T state 0 0 0 1 0 Normal receiving status 1 0 0 0 1 Normal launch status 0 1 1 0 0 Turn off 1 1 1 0 0 Turn off

[0078] Transceiver control timing

[0079] State 1: Normal transmit / receive state, R / EN=0, T / EN=0, SWITCH=0 is the receive state, SWITCH=1 is the transmit state.

[0080] State 2: Off state, power supply to the antenna module is turned off. When R / EN=1 and T / EN=1, switching SWITCH does not change the antenna state.

[0081] Temperature monitoring: Each 1×10 module is equipped with a temperature sensor. The temperature sensor outputs an analog signal, which is converted into a digital signal by an AD converter and then transmitted back to the FPGA via the IIC bus. When the antenna is working normally, the temperature of each T / R chip is monitored in real time, and the real-time temperature information is transmitted back to the host computer monitoring program.

[0082] The beam control algorithm processing module mainly completes the solution of beam control data, realizing the calculation of the angle to the 40-channel VM voltage. The beam control algorithm processing module mainly consists of three parts: trigonometric function operation, 40-channel phase calculation, and table lookup calculation of the I and Q voltages corresponding to the 40-channel phase (calibration data is stored in the data table).

[0083] The main technical specifications are as follows:

[0084] Input: Off-axis angle (θ), frequency

[0085] Output: 40 channels of voltage I and Q values

[0086] DA voltage output real-time requirement: ≤30μs

[0087] The amplitude and phase calibration raw data is stored in the EEPROM of each wave control sub-board. The VM data of each wave control sub-board is stored separately. After the wave control system is powered on and initialized, the calibration data in the EEPROM is loaded into the FPGA buffer for I and Q voltage lookup table output.

[0088] The microwave subsystem consists of a control module, a frequency synthesizer, and a receiver, and mainly performs functions such as waveform generation, power amplification, reference signal generation, echo signal amplification, and filtering. Its main technical parameters are as follows:

[0089] Operating frequency

[0090] It has frequency agility capability;

[0091] Transmit excitation signal

[0092] Noise level amplitude within the linear dynamic range: 6–10 mV (RMS value) (including components).

[0093] The frequency synthesizer first uses a 100MHz high-performance temperature-controlled crystal oscillator to generate the 100MHz frequency reference signal required by the system. After power division and isolation amplification, it generates three reference signals. One of these signals, through a PLL2 circuit, generates two second local oscillator signals with a frequency of 940MHz, forming a continuous wave signal. One of these signals is sent to the receiving down-conversion channel, while the other participates in the up-conversion of the complex signal generated by the DDS circuit to the L-band. Another reference signal, through a PLL1 circuit, generates continuous wave signals at frequencies of 7920, 7945, 7970, 7995, 8020, 8045, and 8070MHz. After power division, each signal is doubled, and one of these signals is mixed with the complex L-band signal to generate the transmit excitation signal. Another of these signals is sent to the receiving channel as the first local oscillator signal for down-conversion. The third reference signal serves as the reference signal for the DDS circuit. After frequency multiplication, it generates the DDS input reference signal, which, after passing through the DDS, produces a complex waveform signal with a carrier frequency of 60MHz.

[0094] The receiving channel of the microwave system is a superheterodyne double mixer, consisting of a low-noise amplifier, an image rejection mixer, an intermediate frequency amplifier, filters, and SFC and MGC.

[0095] The microwave signal, after being amplified by low noise, enters the mixer and is mixed with the first local oscillator signal to generate the first intermediate frequency (IF). After amplification and filtering, it is mixed with the second local oscillator signal to generate the second IF. This second IF is then amplified and filtered again before being sent to the signal processor for direct sampling. The IF section is equipped with STC and MGC to accommodate signal strength requirements at different distances.

[0096] The control module and complex signal generation unit primarily implement communication functions between the microwave system and signal processing, timing generation and control functions, and complex signal generation functions. It also performs fault detection and reporting for various circuits within the microwave system. This circuit mainly consists of two parts: a control interface unit and a complex waveform generation unit.

[0097] Control Interface Unit

[0098] The control interface unit mainly performs the communication functions between the microwave system and signal processing, and controls the microwave system after processing the instructions received from various working modes.

[0099] This system has complex control logic and requires intricate logic and timing control, necessitating large-scale programmable devices. Considering the AD9957 DDS chip's I / O interface voltage of 3.3V, and comparing the characteristics of various programmable devices, an FPGA chip was chosen as the core device to generate timing data and control the system's logic. This chip offers numerous advantages, including high integration, good versatility, flexible design, and easy programming.

[0100] Complex signal generation unit

[0101] Complex signal generation employs an FPGA+DDS synthesis method to produce the various complex signals required by the radar system. In this unit circuit, the input 100MHz signal is frequency-multiplied to generate 480MHz as the reference clock for the DDS chip. After passing through the DDS, various signal waveforms required by the radar system are generated, filtered, amplified, and then output to the up-conversion circuit. The FPGA, with a core operating voltage of 1.8V, consumes only 800mW and provides both parallel and serial interfaces. This satisfies the technical requirements of this radar system and facilitates control.

[0102] Digital processing system

[0103] Working principle

[0104] The digital processing system is primarily used to suppress ground clutter in radar echoes, detect target echo signals, measure target position parameters, and perform data processing and target route management. Additionally, the digital processing system also functions as a control unit, providing central station control, positioning equipment information fusion, and fault detection and location. Electrical requirements include fully digital processing and low-power design; structural requirements include high density and small size; and system requirements include high reliability. The target identification module classifies targets through Doppler frequency domain analysis of the target echo signal.

[0105] This digital processing system is designed for searching and monitoring ground battlefield targets and is an important component of the target detection radar. The target detection radar is a two-dimensional range and azimuth search and tracking phased array radar capable of ±45° area electronic scanning. Compared to general detection radars, it features lighter weight, smaller size, lower power consumption, flexible power allocation, higher accuracy, and higher data rate. For the digital processing system, due to its integration of signal processor and control unit functions—the signal processor handling high pulse compression ratios and large-point MTD, and target detection in complex ground environments, while the control unit handles search and TAS beam scheduling, timing arbitration, and data processing—the amount of information processed and the complexity of the processing are greatly increased. Its main tasks include:

[0106] Complete the detection of radar echo signals;

[0107] Complete the determination of the target's distance, orientation, speed, and characteristics;

[0108] Complete TWS tracking of the target;

[0109] Complete TAS tracking of the target;

[0110] Complete beam pointing management function;

[0111] Complete the functions of positioning device control and data fusion;

[0112] Provides timing signals for the entire system;

[0113] Control the operating mode of the entire system;

[0114] It has serial communication with the terminal;

[0115] It has serial communication with the wave controller.

[0116] Control the fault diagnosis of the entire system and receive fault reporting information from subsystems.

[0117] To accomplish the above tasks, the digital processing system uses a large board design to perform signal processing and control functions.

[0118] Signal processing: After A / D conversion, DDC, pulse compression, secondary cancellation MTI, MTD, CFAR constant false alarm rate processing, clutter map, beam lobe compression, video accumulation, statistical threshold detection, sum-difference ratio amplitude angle measurement, wave standing interval PRF parameter measurement, and characteristic quantity measurement are used to complete the detection of radar echo signals and the extraction of target information.

[0119] The actual control unit (ACU) processes the target information received after signal processing, completes the target's TAS function, generates timing signals for the entire system, communicates with other subsystems through multiple serial ports, and completes the transmission of data, commands, self-test and fault information between subsystems.

[0120] The digital processing system design employs a large number of advanced VLSI and programmable devices (DSP, FPGA, DDR2) to improve the product's adaptability, reliability, and maintainability.

[0121] Pulse compression

[0122] The pulse compression process is essentially the same as the matched filtering process. Assuming the radar-transmitted signal is x(t), the impulse response of the matched filter (pulse compressor) is h(t) = x*(t0-t), and the output signal of the pulse compression is:

[0123]

[0124] The design uses FPGA to perform convolution operations directly to complete the matched filtering. In order to reduce sidelobes, Hamming weighting is used, and the sidelobe suppression is about 42dB.

[0125] MTD and Modulus

[0126] To detect moving targets and remove ground clutter, MTD processing was applied to 512 / 256 pulses within each CPI of the same range cell. Without windowing, the envelope of the narrowband filter is a Singer function, with sidelobes of only -13.2 dB. Excessive sidelobes are detrimental to multi-target resolution and clutter suppression. Chebyshev weighting was used to design the sidelobes to -60 dB, but this resulted in a signal-to-noise ratio loss of approximately 1.81 dB and a main lobe widening factor of approximately 1.6 times. The signal output from the MTD filter is a complex number, and the modulus was calculated using the CORDIC algorithm.

[0127] Constant false alarm

[0128] When radar operates in cluttered environments, target detection is performed against the clutter background. The detector threshold settings differ from those used in thermal noise environments and must adapt to variations in clutter power to keep clutter-induced false alarms (CFARs) at a low, acceptable level. This signal detection method is called Constant False Alarm Rate (CFAR) detection. Various CFAR processing methods exist for different clutter environments, such as Cell Average CFAR (CA-CFAR), Selected Large Cell Average CFAR (GO-CFAR), and Selected Small Cell Average CFAR, used to suppress fixed-point clutter, ground clutter, and meteorological clutter.

[0129] Based on the characteristics of target detection radar, a GO-CFAR (Go-On-Failure Rate) method is selected, which uses the average of two adjacent cells to maximize the constant false alarm rate (CFAR). This method is used to suppress fixed-point clutter and ground clutter. There are eight cells on each side. The adjacent cells to the left and right of the detected cell should not be included in the average calculation of the CFAR threshold for that cell, to avoid the target signal (typically, a target may occupy three range cells) affecting the CFAR threshold. According to the relevant chapters in "Principles of Modern Radar" by Jerry L. Evos et al., with eight accumulation points and an average of eight cells on the left and eight on the right, the CFAR loss is approximately 2 dB.

[0130] clutter diagram

[0131] To detect tangentially moving targets and suppress slow-moving ground clutter, a DC threshold is formed by time-domain accumulation of the echo DC using a clutter map. This threshold, along with a constant false alarm threshold, is then selected as the criterion for zero-velocity targets. The clutter map input uses the full-channel output of an MTD filter, with a setup time of 15-16 beam sector scan cycles. Because this radar employs electronic scanning in azimuth, its beam pointing accuracy is very high, which is highly advantageous for achieving sophisticated clutter maps.

[0132] Implementation method: The beam is divided into four dimensions: range, beam number, Doppler velocity, and repetition rate. Each time the beam scans for one cycle, all the divided grids are updated. The update principle is as follows: The clutter map threshold is formed by multiplying the corresponding grid by an appropriate coefficient. The clutter map requires a large amount of storage; therefore, two DDR2 chips are used in this design.

[0133] Beam compression

[0134] To ensure that amplitude and angle measurement are performed within the linear region of the radiation pattern, beam compression is applied upon target detection. The algorithm is as follows;

[0135] If a target is detected in the sum and difference channels, the signal amplitudes of the sum and difference channels with the same filter number in the same range unit are subtracted (ΣA-ΔA). When ΣA-ΔA≥ξ (ξ is variable), it is determined that the target has been found in the beam, and the signal processing calculates the azimuth angle of the target. Otherwise, the target is judged as a false target and discarded.

[0136] Sum and difference correction

[0137] The purpose of sum and difference measurement is to measure the amplitude and phase imbalance of the sum and difference channels of the receiver, calculate the correction coefficients, and send them to the correction module to correct the receiver.

[0138] The sum and difference measurements are performed under normal radar system conditions, with a measurement time allocated to 70 μs, and are completed simultaneously with phase correction. Let the sum and difference signals before correction be represented as follows:

[0139]

[0140] Δ t =A·e j·ωt

[0141] By performing a 512-point complex FFT on both the sum and difference signals, the correction coefficients can be obtained as follows:

[0142]

[0143] Where M = 0, the calculation method is expressed by the following formula:

[0144]

[0145] Where: k is a constant coefficient, α is the angular error value. ∑ and Δ are the values ​​of the range cells with larger amplitudes within the tracking gate, respectively.

[0146] Azimuth Angle Measurement

[0147] The azimuth angle consists of three parts: the reference value is determined by the azimuth encoder angle information relative to the ground sent by the terminal, the beam position value is obtained by the beam number and the scanning step amount, and the precision value is determined by the sum and difference beam ratio.

[0148] Because it uses sum and difference beamforming, precise azimuth values ​​can be obtained using amplitude comparison angle measurement. The amplitude comparison angle measurement method uses the amplitude values ​​of the sum and difference echo signals received by the antenna as the basis for azimuth angle measurement. The variation of this amplitude value depends on the antenna pattern and the antenna scanning method. The angle value can be obtained from the known slope k, the sum signal amplitude, and the difference signal amplitude.

[0149] Terminal control subsystem

[0150] Due to the tactical requirements of single-person carrying, the terminal control subsystem will utilize a ruggedized handheld platform as its hardware. The terminal control subsystem mainly consists of a communication control interface unit, an embedded microprocessor, and a radar integrated information processing and display unit. The communication control interface primarily includes a 485 serial interface, an Ethernet interface, and a USB serial interface. The 485 serial interface serves as the radar system's integrated data transmission interface, while the Ethernet and USB interfaces are used for radar networking and user data file exchange. The radar integrated information processing and display unit integrates radar system control, target information, geographic information, and radar fault detection information display functions. The entire control and display software is designed based on the Windows window architecture, featuring a user-friendly human-computer interaction.

[0151] The main indicators are as follows:

[0152] CPU: Telechips series main control chip, 600MHz;

[0153] RAM: 256MB;

[0154] Flash: 8GB;

[0155] Touchscreen: 4-wire resistive touchscreen;

[0156] Power consumption: Maximum 4.8W;

[0157] Dimensions: 132mm × 80mm × 18mm;

[0158] Interfaces: 1 USB port, 1 RS485 port, 1 Ethernet port, 1 422 serial port, 1 headphone output port;

[0159] Operating system: WinCE 6.0;

[0160] Interface display modes: B-type display, PPI-type display, fan-shaped display;

[0161] It can output Doppler audio through headphones;

[0162] It has electronic map functionality;

[0163] Automatic short message generation function.

[0164] Target recognition technology

[0165] Due to limitations in range and azimuth resolution, target detection radar employs target classification and identification techniques for low-resolution applications. Radar target identification technology mainly consists of three steps: target echo data acquisition and preprocessing, target feature extraction, and target classification and identification. Target identification technology in target detection radar is primarily achieved through two methods: frequency domain analysis and time-frequency analysis.

[0166] The spectra of the three types of targets obtained by MTD processing are quite different: the main lobe of the truck's spectrum is narrow and the side lobe changes are small; the main lobe of the human's spectrum is relatively wide and the side lobe fluctuates greatly; the spectrum characteristics of the motorcycle are between those of the truck and the human. Therefore, after time-frequency transformation, feature vectors of some targets can be extracted.

[0167] In the data preprocessing, it has been preliminarily determined which gates may contain targets. Based on this, for the data from the range gates where targets are present, the data from the range gate with the maximum amplitude is extracted each time as the target's echo data, and target characteristic parameters are obtained using methods such as amplitude arrangement, centroid arrangement, and power mean.

[0168] Amplitude Arrangement Method: Since an N-point FFT transformation is performed on the velocity dimension (frequency axis) during the time-frequency transformation, after extracting N points of target data, the position of the frequency axis with the maximum amplitude is rearranged to the N / 2th point, and then the values ​​at other positions are rearranged accordingly. This rearranged data, used as the target's feature vector, can mitigate the influence of target velocity. Even if the same target has different velocities, or different targets have the same velocity, it will not significantly affect the final recognition result.

[0169] Centroid Arrangement Method: First, calculate the position of the centroid of the N data points of the target along the frequency axis. Then, arrange it at the N / 2th point, and rearrange the values ​​at other positions accordingly. Since different targets have different spectral structures—humans have a broad spectrum across the entire frequency axis, while trucks have a more concentrated spectrum—the centroid positions of the spectra of different targets also differ. Rearranging the data based on the centroid position can also serve as the target's feature vector.

[0170] Power averaging method: After FFT transformation, the first and last m points of the N points in the velocity dimension (frequency axis) are set to zero, so only the middle Nm points are taken as target data. The power is obtained by performing a logarithmic operation on the data. The power values ​​are then arranged according to the maximum value (the maximum value is located at point (Nm) / 2). The values ​​of n points before and after the maximum value are taken, and the sum and average of these n values ​​yield the average power P1 and P2. The average power P1 and P2 ranges differ for the three types of targets: trucks have lower P1 and P2 values, typically below -40dB; humans have higher P1 and P2 values, typically above -30dB; and motorcycles have P1 and P2 values ​​in the middle, typically between -40dB and -30dB. Using these as feature vectors for the targets can effectively achieve target classification and recognition.

[0171] The time-frequency analysis method is used to perform a point-based FFT transformation on the frequency dimension, and the position of the maximum amplitude is rearranged to the middle position of the frequency axis, and the values ​​of other positions are rearranged accordingly.

[0172] After rearrangement, the following feature parameters are extracted from the target data:

[0173] The variance of each row of data on the frequency axis: The fluctuations of data for different targets vary in each row of the frequency axis. For trucks, the amplitude variation of each row of data on the time axis is not large, so its variance is the smallest; while the amplitude fluctuation of people is the largest, so its variance should be the largest among the three types of targets; the variance of motorcycle target data is in the middle. By calculating the variance of each row of data in this way, we can obtain the amplitude variance characteristic parameters of different targets on the frequency axis.

[0174] The variance of the slope of the line connecting the point in the middle of the frequency axis (the row with the maximum amplitude) to the corresponding points in other rows: The slope of the echo data of different targets is different between the two rows of the frequency axis. Calculating the variance of the slope of the line connecting the points of these three types of targets can also be used as a target characteristic parameter.

[0175] In previous studies, the aforementioned target features were used for target classification and identification, achieving good recognition results. Alternatively, data processing can be combined with target recognition, extracting target features based on the velocity, acceleration, and other transformation rates of the flight path, thereby further improving the target recognition rate.

[0176] Based on the requirements for single-person portable use of the target detection radar, the microwave subsystem needs to be designed for low power consumption, miniaturization, and integration. During the design process, we will strive to use experimentally verified small circuits to reduce design risks; we will select highly integrated chips and devices to reduce discrete chips and devices, thereby reducing size and power consumption.

[0177] In miniaturization and integrated design, while meeting system specifications and reliability requirements, highly integrated and reusable devices and chips should be selected to reduce system size and power consumption. For example, in the design of the frequency synthesizer front end, when selecting the core of the frequency source—the crystal oscillator—smaller and lower-power crystals should be chosen, within the limits of specifications. These new crystal oscillators consume half the power and are nearly one-third smaller than traditional crystal oscillators. In the waveform signal generation circuit, a highly integrated and low-power FPGA chip, EP1C3T144I7, is used to control the waveform and timing of two DDS signals, reducing the number of components, decreasing the device size, and lowering power consumption from 3 watts to nearly 1 watt. In the reference signal generation circuit, considering both meeting technical specifications and minimizing size and weight, the design no longer uses the previous direct frequency multiplication followed by filtering and amplification technique, but instead employs indirect frequency multiplication. Compared to traditional methods, indirect frequency multiplication saves on amplifiers and filters, reducing the circuit size to half, and correspondingly lowering power consumption and cost.

[0178] To reduce size and weight while ensuring performance, the receiver system design utilizes miniaturized surface-mount packages for the low-noise amplifier and downconverter. The pre-amplifier employs the CHA3666 chip, manufactured using advanced MMIC (Made-in-a-Chip) technology. Besides its significant advantages in performance specifications, it boasts a small size and low power consumption. Chip-based integrated circuits were not chosen primarily to avoid performance issues due to unstable assembly processes. Test results demonstrate that the CHA3666 achieves comparable performance to chip-based systems, and even surpasses them in terms of noise figure (NF). To ensure effective image frequency suppression after mixing, an integrated MMIC chip is used in the image suppression mixer. Through the application of these miniaturized components and technologies, the receiver system's size and power consumption are significantly controlled, while performance specifications fully meet system requirements. This lays the technical foundation for achieving the system's goals of miniaturization, integration, and low power consumption.

[0179] Due to the reduced size, the system contains a greater abundance of electromagnetic signals, making it more susceptible to interference between various signals. This complicates electromagnetic compatibility (EMC) design. Therefore, in connecting circuits with different frequencies, in addition to reasonable layout, attention was paid to signal flow and characteristics. Signals that might interfere with each other were kept as far apart as possible or isolated by large-area grounding. Structural considerations were also taken into account, such as adding partitions to further reduce mutual interference and increase isolation. For high-frequency signals that are easily interfered with, we used independent cavities for shielding to isolate this part of the circuit from the system's electromagnetic environment, ensuring the circuit's performance.

[0180] For heat dissipation, special methods are used for some high-power devices. For example, large pads are designed on the side in contact with the device and connected to the ground plane to increase the heat dissipation area. Metal clamps are added to individual devices to increase the heat dissipation area. Devices with high heat generation are arranged in a reasonable manner to make full use of free airflow for heat dissipation.

[0181] In addition to the considerations mentioned above, we adopted a "large board" design principle in our integrated design, placing all subsystems on a single large printed circuit board. This design breaks away from the traditional modular approach of large modules nested within smaller modules, significantly reducing the system's size and weight, and eliminating cumbersome wiring between modules. Except for necessary RF signal lines, all connections between modules are made through the motherboard, improving the system's integrated performance. To prevent mutual interference between unit circuits and subsequent performance degradation, we implemented separate designs for different power supplies and ground planes for different signals during layout and wiring. Experimental results show that this design is reasonable and feasible, meeting the electromagnetic compatibility requirements of the microwave subsystem and radar station.

[0182] Through meticulous design and experimentation in the aforementioned aspects, the system's size and power consumption were ultimately controlled within the ideal range. While ensuring system performance, the system met the technical requirements of integration, miniaturization, and low power consumption.

[0183] Although the invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, features in the embodiments disclosed herein can be combined in any way, provided there is no structural conflict. The lack of an exhaustive description of these combinations in this specification is merely for brevity and resource conservation. Therefore, the invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A buffered portable target detection radar system package, comprising: include: Mid-frame bracket (100); Buffer side plates (400) are symmetrically arranged on the left and right side walls of the middle frame bracket (100). The buffer side plate (400) includes a mounting side plate assembly (410) disposed on the side wall of the middle frame bracket (100), a shock-absorbing spring (420) uniformly disposed in the side groove of the mounting side plate assembly (410), and an arc-shaped plate (430) disposed in the side groove of the mounting side plate assembly (410) and in contact with the shock-absorbing spring (420). The mounting side plate assembly (410) includes a mounting side plate (411) disposed on the side wall of the middle frame bracket (100) and a mounting groove (412) formed on the mounting side plate (411) on the side away from the middle frame bracket (100). The damping spring (420) includes a first damper (421) disposed on the side wall of the inner cavity of the mounting groove (412) near the middle frame bracket (100), a spring (422) disposed on the first damper (421) away from the middle frame bracket (100), a second damper (423) disposed on the spring (422) away from the first damper (421) and connected to the plane side of the arc plate (430), and a damping ball (424) disposed on the inner side of the spring (422) along the spiral trajectory of the spring (422). An ultrasonic generator is installed inside the cavity of the middle frame support (100). An ultrasonic transducer is mounted on the side of the arc-shaped plate (430) facing the middle frame support (100), and the ultrasonic transducer is electrically connected to the ultrasonic generator. A vibration sensor is also installed on the arc-shaped plate (430).

2. A buffered portable target detection radar system package according to claim 1, wherein: It also includes first buffer rubber pads (200) symmetrically disposed on the upper and lower side walls of the middle frame bracket (100).

3. A buffered portable target detection radar system package according to claim 2, wherein: It also includes a second buffer rubber pad (300) symmetrically disposed on the front and rear side walls of the middle frame bracket (100).

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