FPGA-based radar pulse pre-sorting machine design (1)

0 introduction

The growing complexity of modern electronic warfare environment becoming increasingly intensive signal, new radar, radar signals of various parameters to various laws change from intensive complex signal environment separation and identification of new radar signal becomes an electronic signal processing problem.

In order to meet the electronic support measures (ESM) real-time signal separation, processing time on the processor offers higher requirements: requires not only the hardware structure of the processor with good design and can continually optimize space, but also devices have higher integration, these have become important factors. After a pair of related devices an in-depth analysis and research, this article using high-speed field programmable gate array (FPGA) devices instead of small chip to design three parameters associated with the comparator for pre-sorting machine design.

1 based on the associated comparator signal pre-sorting principle

Associated comparer technology for high density signal environment hardware pre-sorting has a positive and important significance.

Associated comparator is used to signal the ideas originated from pre-sorting of traditional signal processing methods of radiation source parameter matching method. Currently, the electronic warfare system on radar signal real-time sorting the information available remains the radar signal five parameters: carrier frequency (RF), pulse width (PW), reached the azimuth (DOA), time of arrival (TOA), pulse amplitude (PA). RF General concentration in which several discrete frequency, amass, therefore is to detect the signal processing is one of the most important traits; DOA depends on the relative radar and reconnaissance plane of azimuth, radar and there is no relative motion between the reconnaissance aircraft, DOA is a constant, relative motion, the DOA is changing slowly, this parameter is not supported by the radar signal itself, but also to detect the signal processing is one of the most important traits; due to the radar signal PW itself relatively stable numerical distribution more concentrated, with good stability and convergence, therefore, can also be used as one of the sorting feature; due to the influence of factors too many PA, PA's ride, credibility is not high, generally not as sorting by; TOA General as the primary processor's main sorting and identification parameters preprocessing General nor as a separator. So theoretically pretreatment can use three parameters: RF, PW, DOA.

Sorting system block diagram as shown in Figure 1, pulse separation into pre-sorting and primary separation, pre-sorting for RF, PW, DOA three parameters combined with sorting, completed by FPGA; main sorting centred frequency (PRI) and sorting is completed by the DSP.

According to the RF, PW, DOA constitute three parameters associated with the comparer works as shown in Figure 2.

Each radar signals in space occupies a small box, small boxes Center coordinates can be thought of as radar parameter, small box of size depends on the parameters tolerance, and the receiver's accuracy. As long as the measurement accuracy, it reaches a certain suitable tolerance range, can this little box of pulse to deinterlace, finalize the pulse sequence exists.

2 the design of the associated comparison

As a result of radiation characteristics of diversity and pulse measurement error of the introduction of the radar to intercept system pulse to interlace the following aspects:

(1) as the parameter Jitter measurement error, or have made the argument is an upper and lower threshold defined in a scope.

(2) due to the presence of parameter agile or parameter diversity, making the existence of multiple value parameters (such as frequency agile, diversity, etc.).

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