CAJ | 학술논문

高速运动目标脉间存在越距离单元走动，且多普勒频谱混叠，脉间相参积累困难。利用长时间的信号积累，来提高微弱高速运动目标在低信噪比下的检测性能理论上是一种有效方法，但积累时间长，使得目标回波越距离单元走动，相参积累更加困难。进行速度提前预估计的方法，能很好提高检测性能，但增加了技术难度，并且需要长的检测时间。本文研究一种改进的Keystone变换方法，该方法是通过计算不同模糊系数时的所有回波脉冲峰值位置的方差，记录下方差最小时的模糊系数，利用该模糊系数，结合运用 SINC函数插值实现的变换方法。该变换方法不受目标回波积累时间的限制，无需预先估计目标速度，可同时实现解多普勒模糊和补偿距离走动。仿真结果表明，与进行匹配滤波后相参积累的方法相比，结合最小方差法和 Keystone 变换的方法，能有效补偿距离走动，去除多普勒模糊，有效提高了高速运动目标回波脉冲积累的信噪比，改善了雷达的检测性能。
고속운동목표맥간존재월거리단원주동，차다보륵빈보혼첩，맥간상삼적루곤난。이용장시간적신호적루，래제고미약고속운동목표재저신조비하적검측성능이론상시일충유효방법，단적루시간장，사득목표회파월거리단원주동，상삼적루경가곤난。진행속도제전예고계적방법，능흔호제고검측성능，단증가료기술난도，병차수요장적검측시간。본문연구일충개진적Keystone변환방법，해방법시통과계산불동모호계수시적소유회파맥충봉치위치적방차，기록하방차최소시적모호계수，이용해모호계수，결합운용 SINC함수삽치실현적변환방법。해변환방법불수목표회파적루시간적한제，무수예선고계목표속도，가동시실현해다보륵모호화보상거리주동。방진결과표명，여진행필배려파후상삼적루적방법상비，결합최소방차법화 Keystone 변환적방법，능유효보상거리주동，거제다보륵모호，유효제고료고속운동목표회파맥충적루적신조비，개선료뢰체적검측성능。
The target echo migration usually exceeds a range resolution cell,when the target is moving with a high ve-locity.This causes Doppler frequency spectrum aliasing,and makes it troublesome to accumulate the pulses. Theorily,when the high-velocity target’s signal is at low signal to noise ratio(SNR),accumulating for longer time could develop the detection ability.However,during longer term accumulation,the waves of pulses may exceed several range resolution cells.This makes it much more difficult to pulses accumulation.Estimating speed before detection could develop detection ability in theory.But in fact,it’s very difficult to measure the speed.Even realized,it needs much longer time to archive.This is very difficult to come true in practice.In this paper,theoretical derivation will be carried on particularly.It tells why there would be range migration and Doppler ambiguity,and how to compensate them.Based on the theoretical derivation,a modified method which is based on Keystone transform is put forward.The method is to calculate the differences of all the points of pulses’peaks,which is gotten at different ambiguity factor,and to note the Doppler ambiguity factor when the difference is minimum.This Doppler ambiguity factor can be used to compensate Doppler ambiguity as is shown below.Keystone transform can be realized by the method of SINC interpolation and the method of calculating Doppler ambiguity factor.This method is not restricted by the accumulation time,and doesn’t need to estimate the speed before detection.What’s more,this method could compensate the range migration and Doppler ambiguity without acknowledging the target’s speed.The result shows that,compared with other methods,this method could compensate the range migration and Doppler ambiguity without acknowledging the targets’speeds.It is not restricted by the detection time.It also develops the SNR of the pulses of high-velocity targets,and Radars’detection ability in wideband radar.This method is of great value in practice,especially in millimeter wave radar.