Method for estimating the mutual time delays of satellite communication system signals based on CDMA technology for the passive direction finding problem
Ершов Роман Александрович, О. А. Морозов, I. V. Grin’, Vladimir R. Fidelman · 2018 Moscow Workshop on Electronic and Networking Technologies (MWENT) · 2018
To solve the simultaneous positioning of multiple radiating objects problem by the range-difference method in satellite communication systems based on code division multiple access technology (CDMA) an algorithm for estimating the mutual time delays of signals propagation is proposed. The Maximum Likelihood method was used as a base to compose proposed algorithm but was reduced to the cross-correlation functions calculation of signals transmitted by satellites. Also to eliminate ambiguity of time delay identification was composed an algorithm based on the sequential exclusion of estimated delays from received signals and the subsequent correlation processing. The exclusion of delays is based on the forming of “difference signals” by the sequential applying of digital processing operations: the signal shift by a specified number of samples and subtraction one signal from another. To examine the efficiency of proposed algorithm the simulation is carried out. Its stability to errors in estimating time delays by the correlation method is investigated. The proposed algorithm is stable at sufficiently low SNR signal noise ratios <;0 dB.