CN113466805B - A multi-base radar anti-interference method based on spatial power characteristic domain - Google Patents
A multi-base radar anti-interference method based on spatial power characteristic domain Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/36—Means for anti-jamming, e.g. ECCM, i.e. electronic counter-counter measures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/003—Bistatic radar systems; Multistatic radar systems
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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Abstract
The invention relates to a multi-base radar anti-jamming method based on a space power characteristic domain, and belongs to the technical field of radar signal processing. Firstly, collecting radar intermediate frequency echo data and caching, then carrying out pulse compression processing on the echo data, calculating the airspace energy coefficients of all distance segments of each coherent pulse, then constructing a signal-to-noise ratio function of a spatial feature domain, then judging whether the signal is an interference signal or a target echo signal according to a threshold of the spatial power feature domain, if the signal is the interference signal, estimating a mark distance gate through parameters, feeding back the mark distance gate into the signal processing, thereby effectively inhibiting the interference signal and effectively improving the target detection probability. The invention relates to a method for solving the problem of multi-base radar combined anti-suppression interference under complex electronic interference, which can effectively inhibit interference signals, improve target discovery probability and improve situation awareness.
Description
Technical Field
The invention belongs to the technical field of radar signal processing.
Background
The multi-base radar in the new system radar has unique freedom degree advantage facing the increasingly complex battlefield situation. Aiming at electronic interference, particularly supporting suppression interference, the multi-base radar can convert interference entering from a main lobe of a single base into side lobe interference of other base radars by utilizing geographic position advantages, and then remove the side lobe interference by adopting means such as fractional Fourier transform, signal noise subspace, chaos measurement and the like of a time domain, a frequency domain, an energy domain or a polarization domain, but all the methods for suppressing the interference inevitably bring about conversion domain loss of a target signal and improvement of false alarm probability. Therefore, aiming at how to effectively inhibit interference signals by electronic interference, particularly supporting type suppression interference, encountered in the multi-base radar, the method does not influence the conventional signal processing flow, does not increase extra engineering operation amount, and reduces the loss of signal to noise ratio, which is a key technology for radar target detection.
The university of electronics technology discloses a multi-base radar anti-jamming method in the patent literature of the invention of the application of the university of electronics technology, namely an anti-deceptive jamming method of a multi-base synthetic aperture radar system (publication number: CN110058233A, application number: CN 201910350079.3). The method mainly utilizes the maximum stable extremum region and the Euclidean distance discrimination-based method to inhibit false targets, but the method can not effectively avoid the signal-to-noise ratio loss of target signals, mainly relies on airspace to inhibit interference, and the specific type of anti-interference is limited.
The document 'multi-base radar main lobe interference resisting algorithm based on blocking preprocessing' (electronic and information journal, 2014, vol.4, pp: 734-738) proposes that 'direct matrix inversion is utilized to quickly obtain an initial weight vector', and then a high-order cumulant is introduced into a forgetting factor-changing recursive least square algorithm, so that iterative weight vector updating is accelerated by the method. However, the algorithm requires stringent requirements for analyzing the data object samples, and there are problems of convergence and computational complexity when the data samples are large. Also unavoidable is the additional loss of signal-to-noise ratio to the target signal.
Disclosure of Invention
Aiming at the situation that one of the multi-base radars is subjected to electronic interference, particularly under the supporting type interference suppression condition, intermediate frequency radar echo data received by each radar receiver are mixed into interference signals, the invention provides an anti-interference method which does not need to destroy the original radar signal processing flow, has small target signal to noise ratio loss and detection probability not lower than that of the traditional multi-base joint cancellation, and solves the problems that interference targets cannot be removed in the processing process of the prior art, and additional signal processing flows are added.
The specific technical scheme is as follows:
1) The method comprises the steps of collecting radar intermediate frequency echo data, constructing a radar intermediate frequency echo data matrix, setting a one-to-many receiving mechanism, and assuming that K radar receivers are arranged in total, and a K-th radar receiver system received signal mathematical model is as follows:
rk(t)＝sk(t)+Jk(t)+n(t)
Wherein the target echo signal r k (t) is a k×1 dimension vector, expressed as follows:
R Tnk and f Tnk in the above formula represent the target radial distance and doppler frequency of the nth target relative to the kth receiver, respectively, and assuming that λ is the wavelength of the radar electromagnetic wave, the total number of targets is N, α Tnk represents the amplitude information of the targets received by the kth receiver, expressed as follows:
Where P T represents the transmit power of the transmitter, G T and G k represent the antenna gains of the radar transmitter and the kth receiver, σ nk is the radar cross-sectional area of the target for the kth receiver, and each receiver is independent of the other, R Tn and R nk represent the radial distances of the radar transmitter and the kth radar receiver, respectively, from the target, and the received interference signal can be expressed as:
Where J k (t) represents the complex envelope signal of the interfering signal received by the kth receiver, R Jk and f Jk represent the radial distance between the kth receiver and the jammer and the doppler frequency of the jammer loading, respectively, and β k represents the amplitude of the interfering signal received by the kth receiver, expressed as follows:
Wherein P J represents the transmitting power of the jammer, R Jk represents the radial distance between the jammer and the kth radar receiver, and the amplitude of the interference signal is only related to the interference power of the jammer and the radial distance between the jammer and the radar receiver assuming that the hardware parameters of the radar receivers are the same;
2) Pulse compression processing is carried out on the radar intermediate frequency echo data, and airspace energy coefficients are calculated according to the echo signals after pulse compression, wherein the airspace energy coefficients are as follows:
|rk1(t)|2＝|καnk1+βk1|2
The above formula is defined for the K1 receiver of the K receivers for an energy coefficient at a single range bin, where K represents the power benefit of pulse compression, and α nk1 and β k1 represent the amplitude values of the target signal and the interfering signal, respectively, relative to the radar receiver;
3) Constructing a spatial feature domain signal-to-noise ratio function, wherein the spatial feature domain signal-to-noise ratio function is set as follows:
The method comprises the steps of providing that information of target echoes received by different radar receivers cannot exceed one distance unit after time registration, wherein m of the formula is valued from 0 to K-1, and specifically classifying whether the distance unit contains target echo signals into two types of cases, if no target exists, the method can be expressed as follows:
the ratio of the above formula is a constant parameter and is only related to the position distribution of the multi-base radar, if the range unit contains the target signal, it can be further expressed as the power ratio of the target, which can be expressed as follows:
The above formulas R nk2 to R nk1 and the ratios of |sigma nk1 | to |sigma nk2 | relate to the spatial distribution of each radar receiver and the attitude angle and properties of the target, if for coherent processing radar, the final spatial signature domain signal-to-noise ratio function can be defined as the average of the pulse-compressed multiple pulse echo signals:
Using the average value calculation to replace the single calculation result;
4) And carrying out one-dimensional constant false alarm detection according to the numerical value of each distance unit obtained by the signal-to-noise ratio function of the spatial feature domain, assuming that P distance units are crossed with a threshold, marking the signal distance units which are crossed with the threshold by D I1 to D IP, feeding back the signal distance units to the distance units subjected to signal processing, reserving the corresponding marked distance unit signals, and carrying out phase-to-phase operation on the output video of normal radar signal processing, thereby extracting the target signals and inhibiting interference signals.
The method solves the problem of multi-base radar combined anti-jamming under complex electronic interference, can effectively inhibit jamming signals, improves target discovery probability and improves situation awareness.
The invention is described in further detail below with reference to fig. 1.
Drawings
Fig. 1 is a process flow diagram of the present invention.
Fig. 2 is a spatial location diagram of the present invention.
Fig. 3 is a graph of the magnitude of the signal-to-noise ratio function calculated according to the spatial power signature after the multi-base radar is interfered in an embodiment of the present invention.
Fig. 4 is a graph comparing the detection probability after processing by adopting the multi-base radar anti-interference method based on the space power characteristic domain with the detection probability of the traditional multi-base joint cancellation method in the specific embodiment of the invention.
Detailed Description
The invention will be described in detail below with reference to the attached drawings and specific embodiments. The schematic diagram of the multi-base radar anti-interference method based on the space power characteristic domain is shown in fig. 1, and the specific process is as follows:
step one, collecting radar intermediate frequency echo data of each radar receiver and initializing a data echo vector.
Considering the universality and consistency of all radar receivers, the signal mathematical expression of the radar intermediate frequency echo matrix is as follows:
R Tnk and f Tnk in the above formulas represent the target radial distance and Doppler frequency, respectively, of the nth target relative to the kth receiver. And assuming that λ is the wavelength of the radar electromagnetic wave, the total number of targets is N. Alpha Tnk represents the amplitude information of the target received by the kth receiver, and the amplitude of the target echo signal is calculated specifically as follows:
Where P T represents the transmit power of the transmitter, G T and G k represent the antenna gains of the radar transmitter and the kth receiver. σ nk is the radar cross-sectional area for the target of the kth receiver and each receiver is independent of the others. R Tn and R nk represent the radial distances of the radar transmitter and the kth radar receiver, respectively, with respect to the target.
The mathematical model of the interference signal released by the jammer is specifically expressed as:
Where J k (t) represents the complex envelope signal of the interfering signal received by the kth receiver, and R Jk and f Jk represent the radial distance of the kth receiver from the jammer and the doppler frequency of the jammer loading, respectively. β k represents the amplitude of the interference signal received by the kth receiver, and can be calculated as follows:
Where P J represents the transmit power of the jammer and R Jk represents the radial distance of the jammer from the kth radar receiver.
Calculating the energy coefficient of each radar receiver, wherein the energy coefficient of a single distance unit is specifically calculated as follows:
|rk1(t)|2＝|καnk1+βk1|2
where κ represents the power benefit of pulse compression and α nk1 and β k1 represent the amplitude values of the target signal and the interfering signal, respectively, relative to the radar receiver. This formula ignores the radar receiver background noise signal, which is less energy-efficient.
Step three, a spatial feature domain signal-to-noise ratio function constructed according to the self-association attribute of the target and the interference airspace is specifically set as follows:
It is assumed that the information of the target echoes received by different radar receivers does not exceed one distance unit after time registration. The value of m in the above formula is from 0 to K-1. If the final spatial signature domain signal-to-noise ratio function for a coherent processed radar can be defined as the average of the pulse-compressed multiple pulse-echo signals:
k of the above formula represents the number of receivers of the multi-base radar.
And fourthly, reversely labeling the distance units according to the result of the third step. The original signal processing flow is not affected, and the calculation efficiency is improved. And thirdly, carrying out one-dimensional constant false alarm detection on the numerical value of each distance unit obtained by the signal-to-noise ratio function of the spatial feature domain, and assuming that P distance units are crossed with a threshold, marking the signal distance units which are crossed with the threshold by D I1 to D IP, feeding back the signal distance units to the distance units subjected to signal processing, reserving the corresponding marked distance unit signals, and outputting video phase and operation output by conventional radar signal processing, so as to extract a target signal and inhibit an interference signal.
The feasibility of the method of the invention is further verified by experimental simulation as follows.
As shown in fig. 2, it is assumed that four radars form a multi-base radar system in the simulation area, one radar transmits and receives, and the other three radars only receive intermediate frequency echo signals. And the four radars are geographically spaced 1km apart, with specific coordinates (-1000,0), (0, 0), (1000,0), (2000,0) as follows. The two point target signals are respectively a target airplane and an interference airplane, and specific coordinate positions are (60000,40000) and (80000,70000). The speeds of the target and the jammer are (-150, -100) m/s and (-100 ) m/s respectively, the number of coherent pulses is 128, and the pulse repetition period is 200us. The radar transmit and receive antenna gains are both set to 30dB. The radar transmitter power is 120kw and the jammer power is 10kw. The signal-to-noise ratio after pulse pressure of the target is set to 10dB, the radar carrier frequency is set to 3GHz, the radar transmitting signal is set to a linear positive frequency modulation signal, the time width of the signal is set to 20us, the sampling rate is set to 20MHz, and the bandwidth is set to 10MHz. The light speed was set to 3X 10 8 m/s. And assuming that the post-spatio-temporal registration error does not exceed one distance unit.
Fig. 3 shows the magnitude model of a certain coherent pulse group according to the distance unit by distance unit according to the signal-to-noise ratio function obtained by calculating according to the spatial power characteristic domain through the spatial energy coefficient calculation. As can be seen from the figure, the target signal appears at the range gate 1232, coincident with the actual scene. And the target signal has high signal-to-noise ratio information, and after one-dimensional constant false alarm, the marked distances are 1231, 1232 and 1233. After the distance is reversely marked, the traditional signal processing is combined, so that the interference signal can be effectively restrained, and the target detection probability is improved.
Fig. 4 is a graph showing detection probability of different signal-to-interference ratios under the condition that the signal-to-noise ratio is 10dB by the multi-base radar anti-interference method based on the spatial power characteristic domain and the conventional multi-base radar joint cancellation method. It can be seen from the figure that as the signal-to-interference ratio increases, the probability of detection for the target increases. When the signal-to-interference ratio is below-30 dB, the detection probability is difficult to meet engineering application requirements due to factors such as detection loss of a transformation domain, and the traditional method can obtain about 80% when the signal-to-interference ratio is greater than-30 dB. However, the method provided by the invention has about 90% detection probability under different signal-to-interference ratio conditions, which also fully verifies the effectiveness and feasibility of the method.
The invention is not limited to the embodiment, and based on the technical scheme disclosed by the invention, a person skilled in the art can make some substitutions and modifications to some technical features of the invention according to the technical content disclosed without creative labor, and the substitutions and modifications are all within the protection scope of the invention.
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| CN103399303A (en) * | 2013-07-22 | 2013-11-20 | 西安电子科技大学 | Method and system for resisting dense forwarding type defraud interference of airborne radar |
| CN105259540A (en) * | 2015-11-26 | 2016-01-20 | 西安电子科技大学 | Optimization method for confronting active deception jamming by multi-station radar |
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| CN109490845B (en) * | 2018-11-01 | 2022-11-15 | 南京邮电大学 | Method for suppressing main lobe suppressing interference by multi-station radar |
| CN109507649B (en) * | 2018-12-20 | 2022-12-02 | 西安电子科技大学 | Method for resisting main lobe deception jamming of wave diversity array radar |
| DE102019108741B4 (en) * | 2019-04-03 | 2025-02-13 | Dieter Girlich | Noise suppression device for electromagnetic measuring systems, radar measuring systems and use thereof |
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| CN103399303A (en) * | 2013-07-22 | 2013-11-20 | 西安电子科技大学 | Method and system for resisting dense forwarding type defraud interference of airborne radar |
| CN105259540A (en) * | 2015-11-26 | 2016-01-20 | 西安电子科技大学 | Optimization method for confronting active deception jamming by multi-station radar |
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