1.School of Physics and Electronic Information,，Yantai University,，Yantai 264005，China,； 2.Naval Air University，Yantai 264005,，China
Abstract： In the process of radar to sea detection, the near-range sea clutter echo power is high, which seriously affects the radar receiver work and subsequent signal processing. In order to balance the gain and sensitivity of radar receiver, a reasonable design of sensitivity time control (STC) curve is needed. This paper introduces four STC design curve methods using GARCH model, polynomial function, radar distance equation and exponential function, and compares and analyzes the near-range sea clutter suppression performance of the four STC curves by using the measured data under high and low sea conditions. The experimental results show that the STC curves in the form of radar distance equation have significant performance in suppressing sea clutter in both high and low sea states; the STC curves modeled by GARCH model are suitable for low sea states; the STC curves in the form of polynomial and exponential are close to each other in different sea states.
Key words : radar,；sea clutter；sensitivity time control
0 引言
對海雷達(dá)探測海上艦船,、浮冰,、航道浮標(biāo)、漁船等目標(biāo)時,，容易受到海雜波的干擾,。雷達(dá)探測目標(biāo)接收信號過程中，近距離區(qū)域,，海雜波干擾很強,，需要對雜波信號進(jìn)行抑制衰弱，否則將無法區(qū)分雜波信號和目標(biāo)信號，在高海況背景下檢測小目標(biāo)尤為困難,。為確保雷達(dá)接收機能在高,、低海況下正常工作，準(zhǔn)確顯示出檢測目標(biāo),，需要使用靈敏度時間控制(Sensitivity Time Control,，STC)進(jìn)一步擴展動態(tài)范圍，抑制近距離海雜波的強度,，增強遠(yuǎn)距離目標(biāo)的信號強度,，保證接收機的靈敏度，提高接收機的性能[1-6],。文獻(xiàn)[7]論述了一種根據(jù)目標(biāo)的回波電壓隨距離二次方變化的特性,，設(shè)置數(shù)字信號實時控制大動態(tài)中頻放大器的方法，用來解決目標(biāo)信號強度隨距離降低的問題,。文獻(xiàn)[8]提出一種自適應(yīng)增益靈敏度控制的方法,，通過統(tǒng)計距離維信息，對海雜波包絡(luò)進(jìn)行擬合,，形成接收端的反饋來控制系統(tǒng)的靈敏度和視頻畫面質(zhì)量,。文獻(xiàn)[9]中提出一種雷達(dá)接收機靈敏度時間控制方法，根據(jù)雷達(dá)距離方程中雷達(dá)回波功率與雷達(dá)距離四次方成反比的規(guī)律,，對STC控制深度和控制距離分別分擋控制,。許多文獻(xiàn)對STC曲線的設(shè)計方法都有所提出或論述，但是,，STC常規(guī)曲線和其他方式設(shè)計STC曲線的性能對比的相關(guān)研究較少,，本文采用高、低兩種海況的實測數(shù)據(jù)對四種STC設(shè)計曲線方式性能進(jìn)行對比,，希望能得到對高,、低海況不同海雜波背景下有實用性的STC曲線，確保雷達(dá)接收機在不同海況下正常工作,。
