伪随机序列调制信号的多普勒频移估计(英文)

Doppler Shift Estimation of Signals Modulated by Pseudorandom Sequences

讨论了伪随机序列调制信息的多普勒频移和延迟的估计问题。隐藏在非透光残骸内的慢速运动目标反射信号含有周期信息。例如,这些信息可能是由人为或自然灾害后幸存人员的呼吸和心跳引起的。非相关与相关噪声都会导致编码序列薄结构出现误差。提出了一种拥有非相干鉴频器的准最优接收机。该接收机拥有两个相位同步的平行通道。主要讨论了该接收机合成过程的工作条件及其特性。这一合成过程建立在改进的非线性滤波过程基础之上。整个合成过程分为两步:第一步假设信号频率无频移且已掌握该信号处理算法的基本结构;第二步,假设该算法结构未改变,利用信号滤波理论设计了移频控制回路中的滤波器。频移与信号延迟的联合估计序列可用作动态卡尔曼滤波器模型。

The problem of estimating Doppler shifts and delays of signals modulated by pseudorandom se-quences is discussed.It is shown that signals reflected from slow-moving targets hidden among optically opaque wreckages contain some information on targets in the variations of the full phase of a signal over the period that exceeds considerably the pseudorandom oscillation period.For example,these variations in the full phase may result from breathing and heartbeat of those who survived after man-made or natural disasters. Non-correlated and correlated types of noise lead to the errors in a thin structure of code sequences.In this paper a quasi-optimal receiver with non-coherent discriminators is proposed.The receiver has the two parallel channels which are synchronized by phase with a sounding signal.The receiver synthesis procedure, its operating conditions and its characteristics are fully considered.The synthesis is based on the modified non-linear filtering methods.This theory has been used to build the signal processing algorithm.The synthe-sis procedure consists of two steps.At the first step we assume that signal frequency has no shift and the base structure of the signal processing algorithm has been obtained.At the second step we assume that the structure of the algorithm remains unchanged,and using the theory of signal filtering the filter in the control loop for shifted frequencies is designed. It is shown that the sequences of combined estimates of the frequencies shifts and the signal delay can be used as a model of a dynamic Kalman filter.