Abstract:

A mathematical model of mode S signals is built. Accuracy of time of arrival (TOA) measurements by pulse rise edge and best statistical estimation methods are discussed. The way to realize the best estimation is also introduced. Then a novel method is proposed to measure the TOA of mode S signals, in which the measurement is performed after the decoding of mode S signals. The accuracy of the proposed method is improved significantly compared with the single pulse measurement, which can be derived from pulse integration. The influence of sampling on TOA measurement is analyzed and the corresponding solving method is introduced. Finally, synchronization in a multilateration system is discussed and the accurate TOA of signals is used for calibration of synchronization errors among receivers.