Comparison of the performance of different radar pulse compression techniques in an incoherent scatter radar measurement

摘要

Improving an estimate ofan incoherent scatter radar signal is vital to provide reliable and unbiased information about the Earth's ionosphere. Thus optimizing the measurement spatial and temporal resolutions has attracted considerable attention. The optimization usually relies on employing different kinds of pulse compression filters in the analysis and a matched filter is perhaps the most widely used one.A mismatched filter has also been used in order to suppress the undesirablesidelobes that appear in the case of matched filtering. Moreover, recently anadaptive pulse compression method, which can be derived based on the minimummean-square error estimate, has been proposed. In this paper we haveinvestigated the performance of matched, mismatched and adaptive pulsecompression methods in terms of the output signal-to-noise ratio (SNR) andthe variance and bias of the estimator. This is done by using different typesof optimal radar waveforms. It is shown that for the case of low SNR thesignal degradation associated to an adaptive filtering is less than that ofthe mismatched filtering. The SNR loss of both matched and adaptive pulsecompression techniques was found to be nearly the same for most of theinvestigated codes for the case of high SNR. We have shown that the adaptive filtering technique is a compromise between matched and mismatched filtering methodwhen one evaluates its performance in terms of the variance and the bias ofthe estimator. All the three analysis methods were found to have the sameperformance when a sidelobe-free matched filter code is employed.