It is low and catching LPI The radar signal design is a technical focus of signal design of modern radar, the radar signal with the low catching characteristic can’t be catching ESM ferret receiver in the electronic countermeasures environment, even catching, can’t be discerned by accurate sorting either. So while it has LPI characteristic radar signal that designed, need low catching characteristic in the radar signal unify the assessment, design one LPI of radar signal assess system, can offer very kind help to the intersection of radar signal and low catching verification of characteristic. This text is on the basis of this, design through GUI of MATLAB, the sorting algorithm of the radar signal, and the arrangement of radar signal environment, unified on the human-computer interaction interface, it is ocular and transparent to calculate and sort the result, it is swift and convenient to use.

Two are unified that different radar signals that Institute of Computing Technology designs resist and sort the characteristic to need: Sort unity and sorting algorithmic unity of the environment. While calculating like this, could be so correct as to publish the same signal and sort on environment and the same sorting algorithm different radar signals resist the result of calculation which sorts the characteristic, complexity factor.

A radar signal is sorted

It is an important constituent element in radar countermeasure that the radar signal is sorted, the signal that it deals with is a video pulse stream of intensive crossover which the radar receiver sends here, isolate each radar pulse train and elect the useful signal from the pulse stream of such random crossover. Can recognise the parameters of different radars and they in the space accurately, and put it into radar storehouse in order to step forward. Divide and choose in the radar signal, the more parameters used are, the more accurate the result sorted is.

1. 1 adds up to the straight side’s graphic calculation CDIF of difference

Accumulate the difference histogram Cumulative Difference Histogram It is a kind of improved algorithm based on periodic pulse temporal correlation principle, its basic principle is to estimate PRI that may exist in primitive pulse train by accumulating the difference histograms at all levels, and carry on the array search according to this PRI.

First of all, calculate the difference of adjacent TOA, namely calculate TOAn -TOAn-1 ,Form the difference histogram of first step, then confirm that measures the threshold and gauge statistics according to measuring the threshold. Set independent variable of the histogram as , assume general sampling time is ST, then the door of detection of CDIF histogram is limited to:

Tthreshold =X ST/ 1

Among them. X is the adjustable coefficient, generally fetch x <1?

Secondly, from minimum pulse spacing, in the difference histogram of first step, each alternate histogram and value of the double and alternate histogram compare with detection threshold, if these two values both exceed and measure the threshold, regard this interval as PRI and carry on the array search.

CDIF algorithm need histogram, each the intersection of PRI and alternate histogram and double the intersection of PRI and alternate value of histogram compare with threshold, if these two values both exceed the threshold, just search for. Situation existing that this is for the second harmonics, namely exist enough interval of number for 3 pulse train of PRI but it has enough intervals of number to be two the intersection of pulse and gradate situation and design of PRI.

If array search for succeed, the intersection of PRI and array this deduct in sampling pulse train, and is re-formed the new CDIF histogram from difference histogram of first step by the surplus pulse train, this course will have gone down repeatedly all the time there is not sufficient pulse that form pulse train in the dashpot. If it is unsuccessful to search for, carry on the search of array as PRI with the next one’s eligible pulse spacing value in this grade of histogram; If there is no eligible pulse spacing value in this grade of histogram, calculate the difference histogram of the next grade and carry on totalizing with the first class difference histogram ago, then compare with measuring the threshold, CDIF algorithm sorts algorithms and has the characteristics that it is insensitive to lose to interference pulse and pulse more conventionally.

1. Straight side’s graphic calculation SDIF of 2 array difference

Straight side’s graph method SDIF of array difference Sequential Difference Histogram It is one kind that is accumulating the straight side’s graphic calculation CDIF of difference Improved algorithm at the foundation, including PRI confirm with the array searching two parts too.

Reach mistiming and form the bad histogram of an array to every one, calculate and measure the threshold; The sub harmonic wave regards all values which exceed the threshold as the possible PRI value and carries on the search of array after examining. If succeed in isolating pulse train, repeat this course, until isolate all pulse train or have less than 5 pulses left. If the array searches and can’t isolate pulse train, calculate the next grade reaches mistiming, set up new threshold, repeat the whole course.

2 radar signals sort environment simulation

The real signal that the catching receiver of radar receives is a alternating-sign pulse train, interlocked with interfering with the pulse signal, pulse signal of the noise by the multiplex radar signal.

It is low and catching LPI The radar signal design is a technical focus of signal design of modern radar, the radar signal with the low catching characteristic can’t be catching ESM ferret receiver in the electronic countermeasures environment, even catching, can’t be discerned by accurate sorting either. So, while it has LPI characteristic radar signal that designed, conduct the unified assessment on need to the low catching characteristic of the radar signal, design one LPI of radar signal assess system, can offer very kind help to the intersection of radar signal and low catching verification of characteristic. This text is on the basis of this, design through GUI of MATLAB, the sorting algorithm of the radar signal, and the arrangement of radar signal environment, unified on the human-computer interaction interface, it is ocular and transparent to calculate and sort the result, it is swift and convenient to use.

Two are unified that different radar signals that Institute of Computing Technology designs resist and sort the characteristic to need: Sort unity and sorting algorithmic unity of the environment. While calculating like this, could be so correct as to publish the same signal and sort on environment and the same sorting algorithm different radar signals resist the result of calculation which sorts the characteristic, complexity factor.

A radar signal is sorted

It is an important constituent element in radar countermeasure that the radar signal is sorted, the signal that it deals with is a video pulse stream of intensive crossover which the radar receiver sends here, isolate each radar pulse train and elect the useful signal from the pulse stream of such random crossover. Can recognise the parameters of different radars and they in the space accurately, and put it into radar storehouse in order to step forward. Divide and choose in the radar signal, the more parameters used are, the more accurate the result sorted is.

1. 1 adds up to the straight side’s graphic calculation CDIF of difference

Accumulate the difference histogram Cumulative Difference Histogram It is a kind of improved algorithm based on periodic pulse temporal correlation principle, its basic principle is to estimate PRI that may exist in primitive pulse train by accumulating the difference histograms at all levels, and carry on the array search according to this PRI.

First of all, calculate the difference of adjacent TOA, namely calculate TOAn -TOAn-1 ,Form the difference histogram of first step, then confirm that measures the threshold and gauge statistics according to measuring the threshold. Set independent variable of the histogram as , assume general sampling time is ST, then the door of detection of CDIF histogram is limited to:

Tthreshold =X ST/ 1

Among them. X is the adjustable coefficient, generally fetch x <1?

Secondly, from minimum pulse spacing, in the difference histogram of first step, each alternate histogram and value of the double and alternate histogram compare with detection threshold, if these two values both exceed and measure the threshold, regard this interval as PRI and carry on the array search.

CDIF algorithm need histogram, each the intersection of PRI and alternate histogram and double the intersection of PRI and alternate value of histogram compare with threshold, if these two values both exceed the threshold, just search for. Situation existing that this is for the second harmonics, namely exist enough interval of number for 3 pulse train of PRI but it has enough intervals of number to be two the intersection of pulse and gradate situation and design of PRI.

If array search for succeed, the intersection of PRI and array this deduct in sampling pulse train, and is re-formed the new CDIF histogram from difference histogram of first step by the surplus pulse train, this course will have gone down repeatedly all the time there is not sufficient pulse that form pulse train in the dashpot. If it is unsuccessful to search for, carry on the search of array as PRI with the next one’s eligible pulse spacing value in this grade of histogram; If there is no eligible pulse spacing value in this grade of histogram, can can regarded as the difference histogram of the next grade and carries on totalizing with the first class difference histogram ago, then compare with measuring the threshold, CDIF algorithm sorts algorithms and has the characteristics that it is insensitive to lose to interference pulse and pulse more conventionally.

1. Straight side’s graphic calculation SDIF of 2 array difference

Straight side’s graphic calculation SDIF of array difference Sequential Difference Histogram It is one kind that is accumulating the straight side’s graphic calculation CDIF of difference Improved algorithm at the foundation, including PRI confirm with the array searching two parts too.

Reach mistiming and form the bad histogram of an array to every one, calculate and measure the threshold; The sub harmonic wave regards all values which exceed the threshold as the possible PRI value and carries on the search of array after examining. If succeed in isolating pulse train, repeat this course, until isolate all pulse train or have less than 5 pulses left. If the array searches and can’t isolate pulse train, calculate the next grade reaches mistiming, set up new threshold, repeat the whole course.

2 radar signals sort environment simulation

The real signal that the catching receiver of radar receives is a alternating-sign pulse train, interlocked with interfering with the pulse signal, pulse signal of the noise by the multiplex radar signal.

The pulse train is according to the arrival time TOA to interlock Go on, arrange in an order, make 3 pulse train it reaches time of radar receiver to be:

Usually, the electronic countermeasure divides the signal into two kinds regular signal and complicated signal. Impulse train signal that the signal means the frequency conventionally, impulse width, repetition frequency does not change. Frequency that talk about herein change mean the same all impulse frequency of radar change on sampling time of SIGPROC signal processing. The radar of different systems, such as the warning radar of circular scanning, the height-finding radar that the fan shape scans, scan radar of tracing, so long as constant signal parameter its, regular signals. Their difference only displays in pulse parameter and aerial are modulated. Radar signal beyond the regular signal

All complicated radar signals.

Wen Zhong, has joined frequency agility radar signal, PRI stagger radar signal and 3 kinds of complicated signals of radar signal of PRI modulation in the signal environment, a kind of regular radar signal is regarded as and compared with the signal.

3 GUI interface designed

GUI is that graphical user interface was designed a strong tool in Matlab, the controlling part is abundant, including text Edit Box, static text frame, pull-down menu, select controlling parts such as the frame,etc. only. Through the constituent graphical user interface of various controlling parts, the human-computer interaction interface that can design the function to be abundant through the operation of mouse and keyboard, input and revise the parameter, the program execution result of real-time display, and can export the three-dimensional curve of two peacekeeping, the ocular one represents the output result.

The intersection of GUI and window that design originally shown as Figs. 3, 4, 5, interface including radar signal choose and signal sort the environment set up, sort the result, reveal, calculate mainly. Mainly shake to frequency agility signal, PRI in the article and the modulation signal is resisted and sorted the calculation that is discerned to verify, the result includes sorting the consequential representing and calculation of the complexity factor.

4 sorts result showing and complexity factor

The complexity factor is to appraise the radar signal and resist and sort the quantized index of the characteristic, so the calculation of the complexity factor needs to include signals through sorting used time, sorting the rate of accuracy. Can compare complexity factor of the complicated radar signal with regular radar signal, weigh the resisting and sorting the characteristic of radar signal. Prove complexity is the bigger in the platform, indicate the more difficult to be sorted correctly the signal is.

It is selected time T0 unit as that the result calculates of regular radar signal second s according to sorting And sort and discern the intensity S0 pulse number and general incoming pulse number ratio sorted correctly, zero dimension ,Define pulsing complexity is 1 conventionally. Then fix 3 complicated radar frequency-agile radars SIMFAR And PRI stagger radar signal and radar signal of the PRI modulation, calculate the sorting time T1, T2, T3 of the radar signal sequentially And sort the order of accuarcy S1, S2, S3 . As shown in Table 1, calculate the complexity factors of 4 radar signals, the required time and the same regular signal intercomparison of rate of accuracy, sort of sorting of the complicated radar signal, calculate the complexity factor of the complicated signal, the complexity factor of the complicated signal is far greater than the complexity factor of the regular signal far.

Calculate the complexity factor of the signal:

5 conclusions

It is a key index which weighs the might of the radar signal that the radar signal one resists and sorts the characteristic, so need the resisting and sorting the characteristic of artificial radar signal of the experiment in the course of designing the radar signal. And it is mature accumulation difference and bad straight side’s graphic calculation of array to sort algorithms in radar signal that adopts in this text, utilize graphical user interface the intersection of radar and signal imitation and sort the intersection of algorithm and the intersection of simulation and organic combination, get to a visual graphical user interface, sort algorithms available, strengthen mutual ability, it is convenient to demonstrate, have commonability at the same time. Pass the rate of accuracy of sorting of 3 kinds of assumed complicated signal and a kind of regular signal in the article, computation complexity and it weighs and resists the intensity which sort the characteristic, can verify the resisting and sorting the characteristic discerned of other radar signals in actual application at the same time, and increase other sorting algorithms, the good and bad intensity when the comparative radar signal opposes different sorting algorithm systems. Can play very good auxiliary function in the design of the low catching radar signal.