Experimental Study on a Modif i ed Method for Propagation Delay of Long Wave Signal

The propagation of a long wave signal is influenced by many factors, such as topography, geology, and weather. How to get the accuracy signal propagation delay has always been the bottleneck restricting the realization of high-precision timing of a long wave system. Now, there are two methods to obtain the signal delay, the calculation and the measurement. The error of the calculation value is caused by the propagation path condition including of topography, geology, and weather. For users in a range, the conditions are similar on the path, and there is the correlation in the error. The relevance of the error is analyzed in theory, and a correction method of signal propagation delay is proposed. Similar to the local area differential Global Position System (GPS), in the reference station, we measure time delay, calculate the error, and send to users. The users around the reference station receive the value and modify the calculation value to get the accuracy delay. The results show that it can effectively improve the accuracy of propagation delay. For the users, the closer it is to the differential station, the higher the correction accuracy is. For the reference stations, if it is farther away from the transmitter, the users’ correction accuracy around it will be higher than others users around with the same distance.