(A) study on the aircraft target classification and localization with ground radar

Abstract

This dissertation focuses on the signal processing related to target classification and positioning through ground radar system. In this dissertation, we used jet engine modulation (JEM) signature which is widely used for non-cooperative target recognition (NCTR) and the positioning error and compensation due to atmospheric refraction effect are mentioned. In the first part, we discuss the classification of jet engines through radar. Radar signals scattered by an operating jet engine contain a unique signature that can be used to classify the type of engine, and therefore the aircraft. We present a new algorithm based on the maximum likelihood estimation (MLE) principle that can identify the number of blades of the rotors in the jet engine from the returned radar signal. The proposed algorithm uses the successive interference cancellation (SIC) technique and is assessed with synthetic data as well as real radar data using a mock-up jet engine. The proposed SIC algorithm performs better than previously known jet engine-classification algorithms. In the second part, we deal with accurate target positioning of the target with surveillance radar. The positioning of a target with radar measurements could be inaccurate because of the atmospheric refraction effects. We present a technique for determining the refractivity parameters using known position information of cooperative targets. The estimated refractivity parameters are then used to find the position of a noncooperative target, along with its radar range and angle measurements. The performance of the proposed algorithm is assessed by comparing the mean square error (MSE) of the estimate with the Cramer-Rao lower bound (CRLB) as well as by testing the algorithm with real field data. Ground-based military surveillance radar can adopt the proposed algorithm and benefit when there are some cooperative flying aircraft while there is no external refractivity information such as radiosonde data.