A Closed-Form Location Algorithm Without Auxiliary Variables for Moving Target in Noncoherent Multiple-Input and Multiple-Output Radar System

Yifan Wei,Ping Wei,Qiu Tang,Wanchun Li,Huaguo Zhang

doi:10.1109/access.2020.2984825

Abstract

This paper focuses on the moving target localization and velocity measurement in incoherent centralized multiple-input and multiple-output (MIMO) radar systems with widely separated antennas in 3D space. In this paper, we assume that parameters such as time-of-arrival (TOA), frequency-of-arrival (FOA), azimuth angles and elevation angles have already been measured. With these measurements, a final closed-form solution of the target position and velocity can be obtained via the weighted least squares (WLS) method. When the target is located in the far field, due to poor system observability, a first-order Taylor expansion based on the WLS solution is necessary to obtain a more accurate and unbiased solution. Unlike the preceding papers which were based on the two-stage weighted least squares (2SWLS) method [1]-[3], in this paper, the angle information is introduced into the time delay equations and the Doppler frequency equations, so that the intermediate variables in the estimator can be eliminated [4], [5]. Meanwhile, the time delay equations and the Doppler equations are transformed into linear equations only related to the position and the speed of the target. This method, unlike 2SWLS-based methods [1]-[3], does not introduce auxiliary variables, so it does not require the decorrelation procedure. Simulation results show that the root mean-square error (RMSE) of position and velocity can reach Cramer-Rao lower bound (CRLB) when the noise is at a moderate level before the thresholding effect occurs.

Highlights

Multiple-input multiple-output (MIMO) radar systems are new powerful configurations with multiple emitters sending diverse waveforms synchronously and multiple receivers intercepting reflected signals [6]
The method in [5] first used the angular measurements to eliminate the intermediate variables in the MIMO radar localization system, but it was only applicable to the stationary target
Consider a centralized MIMO radar system with four transmitters placed at t1 = [−1500, −1500, 200]T m, t2 = [−1500, −1500, 700]T m, t3 = [1500, 1500, 1200]T m, t4 = [−1500, 1500, 1700]T m and four receivers located at r2 = [1500, 0, 1000]T m, r3 = [0, 1500, 2000]T m, r4 = [−1500, 0, 3000]T m.The carrier frequency of the four transmitters are 2.9, 2.96, 3.03, 3.1GHz respectively

Summary

INTRODUCTION

Multiple-input multiple-output (MIMO) radar systems are new powerful configurations with multiple emitters sending diverse waveforms synchronously and multiple receivers intercepting reflected signals [6]. In [21], the authors utilized TOA and Doppler shift to locate a target in a 2D plane using an indirect method They divided the computation into k groups, where k is the number of the receivers. The method in [5] first used the angular measurements to eliminate the intermediate variables in the MIMO radar localization system, but it was only applicable to the stationary target It just utilized AOA and TOA information. The structure of our paper lies as follows: in section II, we present the measurement model and formulate the location problem to estimate target position and velocity in 3D space. Matrices and scalars are denoted by bold lowercase, bold uppercase letters, and italic respectively. · represents the 2-norm. [] denotes the transpose operation. [A]k,l indicates the (k, l) th element of A

PROBLEM FORMULATION

ANGLE MEASUREMENTS The measurements of azimuth are modeled as θkl

LS SOLUTION FOR THE TARGET

SIMULATION RESULTS

TARGET IN NEAR FIELD

CONCLUSION