Rate of Phase Difference Change Estimation in Single Airborne Passive Locating System

As an important parameter in the single airborne passive locating system, the rate of phase difference change contains range information of the radio emitter. Taking single carrier sine pulse signals as an example, this article illustrates the principle of passive location through measurement of rates of phase difference change and analyzes the structure of measurement errors. On the basis of the Cramér-Rao lower bound (CRLB), an algorithm associated with time-chips is proposed to determine the rates of phase difference change. In the measurement of the rates of phase difference change, phase discrimination in the frequency domain outperforms that in the time domain when signal noise rate (SNR) is lower. Multi-chip processing can significantly reduce variance of the measurement of rates of phase difference change. Simulations demonstrate the validity and accuracy of the proposed algorithm. The simulations carried out on the typical single airborne passive location have proved its adaptability to dynamic measurements. The proposed algorithm to determine the rates of phase difference change proves simple and easy to implement with less computation workload.