CN105044687A - SMSP interference identification and parameter estimation method based on PWD-Hough conversion - Google Patents

Abstract

The invention discloses a SMSP interference identification and parameter estimation method, belongs to the radar signal parameter estimation technology field and especially relates to a radar interference signal parameter estimation technology. The method is characterized by carrying out Hough conversion on pseudo wigner of a radar receiving signal, carrying out energy accumulation on all the points on a receiving signal time-frequency plane straight line at one point on a new coordinate plane so as to form a peak; and finally through extracting a peak coordinate position, estimating an interference parameter and identifying an interference type.

Description

A kind of SMSP disturbance ecology based on PWD-Hough conversion and method for parameter estimation

Technical field

The invention belongs to radar signal parameter estimation techniques field, it is in particular to Radar jam signal parameter estimation techniques.

Background technology

Along with the development of gate stealing, particularly based on the appearance of the active deception jamming technology of digital radiofrequency memory (DRFM), modern radar is operated in day by day complicated electromagnetic interference environment, and this brings the accuracy of radar target acquisition and the stability of target following and greatly challenges.The SMSP interference particularly occurred in recent years, it has the dual interference characteristic of compacting and deception simultaneously, multiple decoy can be produced in distance after entering radar receiver, and real goal is buried in decoy group, make Radar Targets'Detection be faced with increasing difficulty, bring extremely stern challenge to the viability of modern radar.

Taking before a series of interference protection measure comes Anti-amyloid-β antibody, in order to improve the utilization factor of radar resource, first we will identify which kind of interference is electronic interferences be, and estimate its parameter.In recent years, for the identification problem of SMSP interference, Li Yong equality proposes a kind of recognition methods based on ambiguity function, the method is by solving the ambiguity function of radar return signal, extract its characteristic parameter such as peak value number and peak separation to identify that SMSP disturbs, see [Li Yongping, Lu Gang etc.Based on SMSP and the C & I disturbance ecology algorithm of ambiguity function.Airborne weapon, 2011, (4): 51-54].But the method only considered the situation that radar return signal is only undesired signal and noise, and fail to estimate the parameter of undesired signal.

Summary of the invention

For the deficiency of background technology, the invention provides a kind of identification and method for parameter estimation of practicable SMSP interference, pseudo derivative feedback (PWD) and Hough transform combine by the method, the pseudo derivative feedback of Hough transform to radar return signal is utilized to process, with the impact of restraint speckle and PWD cross term, eventually pass peak extraction, just can estimate the chirp rate of target echo signal and SMSP undesired signal, and the subpulse number of SMSP interference, utilize the characteristic parameter estimated also can identify SMSP interference simultaneously.Thus a kind of SMSP disturbance ecology based on PWD-Hough conversion of the present invention and method for parameter estimation, comprises the following steps:

Step 1: Signal Pretreatment;

Radar constantly outwards launches chirp pulse signal, receives echoed signal simultaneously, when there is SMSP undesired signal in space, is expressed as by radar receiver Received signal strength:

x(t)＝s(t)+j(t)+n(t)

Wherein, x (t) represents passive radar Received signal strength, and n (t) represents additive white Gaussian noise, and s (t) is real goal echoed signal, the undesired signal of j (t) for generating after jammer intercepting and capturing radar signal;

Step 2: signal transacting;

Radar receiver Received signal strength is processed, first the pseudo derivative feedback of Received signal strength is obtained, obtain its time-frequency plane, then Hough transform is carried out to it, then in Received signal strength time-frequency plane on same straight line a little in new parameter space, a bit carry out energy accumulation, form spike;

Step 3: the estimation of interference parameter;

Extract the peak location coordinate on new coordinate surface in signal transacting step, its angle coordinate reflects signal chirp rate, and meet the relation of k=tan θ, wherein k is signal chirp rate, θ is peak point angle coordinate, and the corresponding SMSP of the peak point number of same angle coordinate disturbs the number n of subpulse, just can estimate interference signal parameters and identify interference based on this.

The method that the invention has the beneficial effects as follows is simple, disturbance ecology and parameter estimation accuracy higher, can directly apply in Radar ECM equipment.

Accompanying drawing explanation

Fig. 1 is overview flow chart of the present invention;

Fig. 2 is for comprising target echo signal, and the PWD-Hough of the radar return signal of SMSP undesired signal and noise converts;

Fig. 3 is the relative root-mean-square error curve adopting this method to disturb chirp rate to estimate to SMSP.

Embodiment

Specific embodiment of the invention step is as follows:

Step 1: radar constantly outwards launches chirp pulse signal, receives echoed signal simultaneously, and when there is SMSP undesired signal in space, radar receiver Received signal strength can be expressed as:

x(t)＝s(t)+j(t)+n(t)

Wherein, x (t) represents passive radar Received signal strength, and n (t) represents additive white Gaussian noise, and s (t) is real goal echoed signal, the undesired signal of j (t) for generating after jammer intercepting and capturing radar signal.

Step 2: radar return signal in step 1 is processed, first the pseudo derivative feedback of Received signal strength is solved, obtain its time-frequency distributions plane, then the pseudo derivative feedback continued to received signal carries out Hough transform, then on Received signal strength time-frequency plane cathetus a little in new parameter space, a bit carry out energy accumulation, form spike.

Step 3: the peak location coordinate (ρ in extraction step 2 in parameter space, θ) and spike number, wherein ρ is polar radius coordinate, to represent in time-frequency plane true origin to the normal distance of straight line, θ is angle coordinate, represents the angle of ρ and time-frequency plane Y-axis forward.θ reflects signal chirp rate, and meet the relation of k=tan (θ), wherein k is signal chirp rate, θ is peak point angle coordinate, and the corresponding SMSP of the peak point number of same angle coordinate disturbs the number n of subpulse, just can estimate interference signal parameters and identify interference based on this.

Effect of the present invention is further illustrated by following l-G simulation test:

Simulating scenes: suppose radar emission chirp pulse signal, its pulsewidth T=20 μ s, bandwidth B=10MHz, chirp rate k'=B/T=5 × 10 ¹¹hz/s, radar receiver sample frequency f _c=100MHz, the SMSP undesired signal subpulse number n=4 that jammer is modulated after intercepting and capturing radar emission signal, chirp rate k=n × k'=2 × 10 ¹²hz/s, ground unrest is white Gaussian noise, signal to noise ratio snr=10dB, jamming-to-signal ratio JSR=10dB, then the PWD-Hough conversion of radar return signal as shown in Figure 2

As shown in Figure 2, the peak value number of SMSP interference has 4, then SMSP disturbs subpulse number n=4, and the corresponding SMSP of peak point disturbs chirp rate estimated value signal peak has 1, the radar emission signal chirp rate estimated value that its peak point is corresponding and have n=k/k'.

Suppose that signal to noise ratio snr is fixed as 10dB, jamming-to-signal ratio JSR transformation range is-4 ~ 12dB, and step-length is taken as 2dB, carries out 50 independent Monte Carlo Experiments at each jamming-to-signal ratio point, then SMSP disturbs the relative root-mean-square error curve of chirp rate estimation as shown in Figure 3.

From Fig. 2 and Fig. 3, institute of the present invention extracting method can effectively identify that SMSP disturbs, and has good estimation effect to the chirp rate of SMSP interference.

Claims (1)

1., based on SMSP disturbance ecology and the method for parameter estimation of PWD-Hough conversion, comprise the following steps:

Step 1: Signal Pretreatment;

Radar constantly outwards launches chirp pulse signal, receives echoed signal simultaneously, when there is SMSP undesired signal in space, is expressed as by radar receiver Received signal strength:

x(t)＝s(t)+j(t)+n(t)

Wherein, x (t) represents passive radar Received signal strength, and n (t) represents additive white Gaussian noise, and s (t) is real goal echoed signal, the undesired signal of j (t) for generating after jammer intercepting and capturing radar signal;

Step 2: signal transacting;

Radar receiver Received signal strength is processed, first the pseudo derivative feedback of Received signal strength is obtained, obtain its time-frequency plane, then Hough transform is carried out to it, then in Received signal strength time-frequency plane on same straight line a little in new parameter space, a bit carry out energy accumulation, form spike;

Step 3: the estimation of interference parameter;

Extract the peak location coordinate on new coordinate surface in signal transacting step, its angle coordinate reflects signal chirp rate, and meet the relation of k=tan θ, wherein k is signal chirp rate, θ is peak point angle coordinate, and the corresponding SMSP of the peak point number of same angle coordinate disturbs the number n of subpulse, just can estimate interference signal parameters and identify interference based on this.