Digital array echo simulator based on software definition

Abstract

The invention provides a digital array echo simulator based on software definition, which is characterized in that a storage unit completes offline waveform data storage and transmits the stored waveform data to a signal generation unit; the main control unit completes display control, supports target track initialization and configuration of interference, clutter and noise parameters, and transmits the configured parameters to the signal generation unit; and the signal generation unit completes real-time generation of target analog number IQ data streams according to settings and instructions. According to the method, the sub-array-level digital echo signals at the front end of the digital array are simulated, the virtual-real combination capability of a software radar is improved, and parameters are flexibly configured.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of digital array echo simulators based on software definition, mainly for simulating the digital echo signal of the subarray level of digital array front end, improve the "virtual and real combination" ability of software radar. BACKGROUND

[0002] Radar is an electronic device that uses electromagnetic waves to detect targets, and can detect target-related information such as range, speed, pitch, and azimuth angle from target scattering echoes. Its development process requires specific debugging and testing environment to debug and evaluate system function and performance. Currently, there are two options, field testing and laboratory semi-physical simulation testing. The advantage of field testing is that the radar works in real working condition, and the test environment is the real working environment. However, the manpower, financial resources and material resources required for experimental testing are quite large, and the experimental period is relatively long. In addition, field testing is also subject to time, location, weather and other external forces, and the testing difficulty is relatively large, and the testing coverage is difficult to guarantee. Compared with field testing, laboratory semi-physical simulation testing can generate specific echo signals for radar system performance testing by modeling targets and environments in the laboratory. This not only greatly saves the cost of radar development, but also realistically and flexibly meets the needs of radar for various test indicators, test conditions and test coverage, greatly shortening the radar development cycle. Therefore, various types of echo simulators, such as baseband echo simulators, intermediate frequency echo simulators, and radio frequency echo simulators, have become an indispensable part of each stage of radar system development process.

[0003] With the increasing digitalization of radar, digital beam forming (DBF) technology has been applied to radar systems. Radar systems using DBF technology have fast variable beam pointing, low sidelobe and adaptive anti-jamming capabilities. Compared with general single-channel radio frequency radar echo simulators, multi-channel radar semi-physical simulation systems using array antennas can produce multiple radar simulation echoes containing spatial position and velocity Doppler information at extremely fast response speed, and can verify the target search, interception and tracking capabilities of digital array radar systems in the laboratory. In addition, for the function and performance testing of intermediate frequency systems in digital array radar systems, a corresponding multi-channel intermediate frequency simulation system is also needed. Therefore, the development of multi-channel echo simulation systems is very meaningful.

[0004] The current digital array simulator is limited by processing power and transmission capacity, and is generally only used to simulate echo signals of a specific number of channels, and cannot complete signal simulation for large-scale digital arrays. In addition, the external interfaces of the system are designed individually, and the software-defined capability of the system cannot be reflected, so research on digital array echo simulators based on software definition is needed. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the present application provides a software-defined digital array echo simulator, which is mainly used for simulating the subarray-level digital echo signal of the digital array front end, and improving the virtual-real combination capability of the software-based radar.

[0006] The technical scheme adopted by the present application to solve its technical problems is:

[0007] A software-defined digital array echo simulator, comprising a storage unit, a signal generation unit and a master control unit; the storage unit completes offline waveform data storage and transmits the stored waveform data to the signal generation unit; the master control unit completes display control, supports target track initialization, and configures interference, clutter and noise parameters, and transmits the configured parameters to the signal generation unit; the signal generation unit completes real-time generation of target simulation digital IQ data stream according to settings and instructions.

[0008] The master control unit receives and analyzes the uplink control instruction, and then outputs the configuration parameters to the signal generation unit, and outputs the storage control to the storage unit, and calculates the track true value of the echo according to the uplink control instruction, and outputs the track true value to the radar back end;

[0009] The storage unit receives the storage control issued by the master control unit, and sends the stored waveform data to the signal generation unit for use in simulating echo generation;

[0010] The signal generation unit receives the clock and trigger pulse sent by the radar system to ensure that it works synchronously with the radar system, generates subarray-level digital echo signals according to the configuration parameters of the master control unit and the stored waveform data of the storage unit;

[0011] In order to simulate the analog echo signal of the subarray-level digital array radar front end, the analog beam forming in the subarray and the digital beam forming between the subarrays are comprehensively considered; two-dimensional phased arrays are provided, which have MxN units, each unit is divided into PxQ subarrays, the direction of arrival is The beam pointing direction is The azimuth unit spacing is dx, the elevation unit spacing is dy, and the subarray size is AxB, wherein A=M / P and B=N / Q, and C is the number of echo targets.

[0012] is the result of full array beamforming; s(t) is the expression of DDS generated modulated waveform, which includes LFM, simple pulse and phase coded signal; m is the mth unit in the azimuth dimension of the two-dimensional phased array, 1≤m≤M; n is the nth unit in the elevation dimension of the two-dimensional phased array, 1≤n≤N; p is the pth subarray in the azimuth dimension of the two-dimensional phased array, 1≤p≤P; q is the qth subarray in the elevation dimension of the two-dimensional phased array, 1≤q≤Q; a is the ath unit in the azimuth dimension of the subarray, 1≤a≤A; b is the bth unit in the elevation dimension of the subarray, 1≤b≤B; j is the imaginary unit; λ is the wavelength corresponding to the operating frequency f of the two-dimensional phased array, λ=c / f, c is the speed of light;

[0013] The full array beamforming result is

[0014]

[0015] According to the above formula, the subarray IQ data generated by echo simulation is:

[0016]

[0017] The DDS generates modulated waveform, and the data format is zero intermediate frequency complex IQ signal. The zero intermediate frequency complex IQ signal is copied A*B times, corresponding to A*B transmitting units in the subarray. Each road is multiplied by the transmitting beamforming factor in the respective subarray to synthesize 1 road. The synthesized signal is copied into P*Q roads, corresponding to P*Q subarrays. Each road is multiplied by the transmitting beamforming factor between the respective subarrays to synthesize 1 road. The synthesized signal is copied into C roads, corresponding to the target number. Each road signal is multiplied by the target RCS fluctuation factor and the target delay factor, and then synthesized into 1 road data. The road data is copied into A*B roads, corresponding to A*B receiving units in the subarray. Each road data is multiplied by the receiving beamforming factor in the subarray, and then synthesized into 1 road. The synthesized data is copied into P*Q roads according to the number of subarrays, corresponding to P*Q subarrays. Each road is multiplied by the receiving beamforming factor between the respective subarrays, and then added with the interference signal and the noise signal, to finally form the subarray level baseband data of the M*N scale phased array P*Q targets.

[0018] The transmitting beamforming factor in the subarray, the transmitting beamforming factor between the subarrays, the receiving beamforming factor in the subarray and the receiving beamforming factor between the subarrays are generated in real time by the master control unit according to the requirements of the transmitting and receiving beam pointing.

[0019] The interference signal and the noise signal are simulated by the DDS method or read by the storage unit and loaded on each baseband data.

[0020] The main control unit defines the array size M*N and the subarray size (A*B) in real time in a software-defined manner, and simultaneously defines the transmission beam pointing direction, the reception beam pointing direction, the number of echo targets, the target RCS fluctuation factor and the target delay factor, so that the large-scale phased array radar simulation in various scenes is flexibly adapted.

[0021] The beneficial effects of the application are based on a software-defined digital array echo simulator, which is mainly used for simulating the subarray level digital echo signal of the digital array front end, and improving the "virtual-real combination" capability of the software radar. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a schematic diagram of the software-defined digital array echo simulator according to the application.

[0023] Figure 2 It is a schematic diagram of the digital array echo simulation. DETAILED DESCRIPTION

[0024] The application will be further described below in combination with the drawings and examples.

[0025] As shown in Figure 1 a software-defined digital array echo simulator includes a storage unit, a signal generation unit and a main control unit;

[0026] The storage unit completes offline waveform data storage; the main control unit completes display control and supports target track initialization and interference / clutter / noise parameter setting; and the signal generation unit completes real-time generation of target simulation data stream according to the settings and instructions.

[0027] The main control unit receives the uplink control instruction, analyzes it, and then outputs the configuration parameters to the signal generation unit, outputs the storage control to the storage unit, and calculates the track true value of the echo according to the uplink control instruction and outputs it to the radar back end.

[0028] The storage unit receives the storage control sent by the main control unit, sends the stored waveform data to the signal generation unit for use in simulating echo generation according to the requirements.

[0029] The signal generation unit needs to receive the clock and trigger pulse sent by the radar system to ensure the same origin and synchronous operation with the radar system, generate the subarray level digital echo signal according to the configuration parameters of the master control unit and the stored waveform data of the storage unit;

[0030] As shown in the formula (1), the formula (1) is used for simulating the analog echo signal of the subarray level digital array radar front end, and the analog beam forming in the subarray and the digital beam forming between the subarrays are comprehensively considered. Figure 2 As shown in the formula (1), the formula (1) is used for simulating the analog echo signal of the subarray level digital array radar front end, and the analog beam forming in the subarray and the digital beam forming between the subarrays are comprehensively considered. Beam pointing The azimuth unit spacing is dx, the elevation unit spacing is dy, and the subarray size is A x B, wherein A = M / P, B = N / Q, and C is the number of echo targets.

[0031] Definition: is the result of the full array beam forming; s(t) is the expression of the DDS generated modulation waveform (including LFM, simple pulse and phase coded signal); m is the mth unit in the azimuth dimension of the two-dimensional phased array (1≤m≤M); n is the nth unit in the elevation dimension of the two-dimensional phased array (1≤n≤N); p is the pth subarray in the azimuth dimension of the two-dimensional phased array (1≤p≤P); q is the qth subarray in the elevation dimension of the two-dimensional phased array (1≤q≤Q); a is the ath unit in the azimuth dimension of the subarray (1≤a≤A); b is the bth unit in the elevation dimension of the subarray (1≤b≤B); j is the imaginary unit (j 2 = -1); λ is the wavelength corresponding to the working frequency f of the two-dimensional phased array (λ = c / f, c is the speed of light);

[0032] The full array beam forming result is

[0033]

[0034] According to the above formula derivation, the subarray IQ data of the echo simulation generation is

[0035]

[0036] Referring to the above formula, the DDS generates a modulated waveform (containing LFM, simple pulse, phase-coded signal), and the data format is a zero intermediate frequency complex IQ signal. The signal is copied A*B paths (corresponding to A*B transmitting units in the subarray), each path is multiplied by the transmitting beamforming factor in the respective subarray to synthesize 1 path, the synthesized signal is copied P*Q paths (corresponding to P*Q subarrays), each path is multiplied by the transmitting beamforming factor between the respective subarrays to synthesize 1 path, the synthesized signal is copied C paths (corresponding to the target number), each path is multiplied by the target RCS fluctuation factor and the target delay factor to synthesize 1 path data, the path data is copied A*B paths (corresponding to A*B receiving units in the subarray), each path data is multiplied by the receiving beamforming factor in the respective subarray to synthesize 1 path, and the synthesized data is copied P*Q paths (corresponding to P*Q subarrays) according to the number of subarrays, each path is multiplied by the receiving beamforming factor between the respective subarrays, and then added with the interference signal and the noise signal, to finally form the subarray-level baseband data of P*Q paths of M*N phased array simulating C targets

[0037] The transmitting beamforming factor in the subarray, the transmitting beamforming factor between the subarrays, the receiving beamforming factor in the subarray, and the receiving beamforming factor between the subarrays are calculated in real time by the main control unit according to the requirements of the transmitting and receiving beam pointing.

[0038] The interference signal and the noise signal are simulated by the DDS method or read by the storage unit and loaded on each baseband data.

[0039] The main control unit can define the array size (M*N) and the subarray size (A*B), the transmitting and receiving beam pointing, the number of echo targets, the target RCS fluctuation factor, and the target delay factor in real time by the software-defined method, to flexibly adapt to large-scale phased array radar simulation in various scenarios.

Claims

1. A software-defined digital array echo simulator, comprising a storage unit, a signal generation unit and a master control unit; characterized in that: the software-defined digital array echo simulator, the storage unit completes offline waveform data storage and transmits the stored waveform data to the signal generation unit; the master control unit completes display control, supports target track initialization, and configures interference, clutter and noise parameters, and transmits the configured parameters to the signal generation unit; and the signal generation unit completes real-time generation of target simulation number IQ data stream according to settings and instructions. 2.The software-defined digital array echo simulator according to claim 1, characterized in that: the master control unit receives uplink control instructions, analyzes the uplink control instructions, outputs configuration parameters to the signal generation unit, outputs storage control to the storage unit, and calculates the track true value of the echo according to the uplink control instructions, and outputs the track true value to the radar backend. 3.The software-defined digital array echo simulator according to claim 1, characterized in that: the storage unit receives the storage control issued by the master control unit, and transmits the stored waveform data to the signal generation unit for use in simulation echo generation. 4.The software-defined digital array echo simulator according to claim 1, characterized in that: to ensure that the signal generation unit works synchronously with the radar system, the signal generation unit receives the clock and trigger pulse sent by the radar system, generates a subarray level digital echo signal according to the configuration parameters of the master control unit and the stored waveform data of the storage unit. 5.The software-defined digital array echo simulator according to claim 1, characterized in that: To simulate the analog echo signal of the front end of the subarray level digital array radar, the analog beam forming in the subarray and the digital beam forming between the subarrays are comprehensively considered; a two-dimensional phased array with M×N units is provided, each unit is divided into P×Q subarrays, and the direction of the incoming wave is the beam pointing is the azimuth unit spacing is dx, the elevation unit spacing is dy, the subarray size is A×B, wherein A=M / P, B=N / Q, and C is the number of echo targets; is the result of full-aperture beamforming; s(t) is the expression of DDS generated modulated waveform, including LFM, simple pulse and phase-coded signal; m is the mth element of the azimuth dimension of the two-dimensional phased array, 1≤m≤M; n is the nth element of the elevation dimension of the two-dimensional phased array, 1≤n≤N; p is the pth subarray of the azimuth dimension of the two-dimensional phased array, 1≤p≤P; q is the qth subarray of the elevation dimension of the two-dimensional phased array, 1≤q≤Q; a is the ath element of the azimuth dimension of the subarray, 1≤a≤A; b is the bth element of the elevation dimension of the subarray, 1≤b≤B; j is the imaginary unit; λ is the wavelength corresponding to the operating frequency f of the two-dimensional phased array, λ=c / f, c is the speed of light; the full array beam forming result is according to the above formula, the subarray IQ data generated by the echo simulation is: DDS generates a modulated waveform, and the data format is a zero intermediate frequency complex IQ signal; the zero intermediate frequency complex IQ signal is copied A*B ways, corresponding to A*B transmitting units in the subarray; each way is multiplied by the transmitting beam forming factor in the respective subarray to synthesize 1 way; the synthesized signal is copied P*Q ways, corresponding to P*Q subarrays; each way is multiplied by the transmitting beam forming factor between the respective subarrays to synthesize 1 way; the synthesized signal is copied C ways, C corresponding to the number of targets; each way is multiplied by the target RCS fluctuation factor and the target delay factor to synthesize 1 way of data; the way of data is copied A*B ways, corresponding to A*B receiving units in the subarray; each way of data is multiplied by the receiving beam forming factor in the respective subarray to synthesize 1 way; the synthesized data is copied P*Q ways according to the number of subarrays, corresponding to P*Q subarrays; each way is multiplied by the receiving beam forming factor between the respective subarrays, and then added with the interference signal and the noise signal, to finally form M*N phased array P*Q way subarray simulation C target subarray level baseband data. 6.The software-defined digital array echo simulator according to claim 5, characterized in that: the transmitting beam forming factor in the subarray, the transmitting beam forming factor between the subarrays, the receiving beam forming factor in the subarray and the receiving beam forming factor between the subarrays are calculated and generated in real time by the master control unit according to the transmitting and receiving beam pointing requirements.

7. The software-defined digital array echo simulator according to claim 1, characterized in that: The interference signals and noise signals are simulated by a DDS method or read from a storage unit and loaded on each baseband data.

8. The software-defined digital array echo simulator according to claim 1, characterized in that: The main control unit defines the array size M*N and the subarray size A*B in real time by a software-defined method, and simultaneously defines the transmission beam pointing direction, the reception beam pointing direction, the number of echo targets, the target RCS fluctuation factor and the target delay factor, so as to flexibly adapt to large-scale phased array radar simulation in each scene.

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