Abstract:In view of the limited transmission power of satellite, a new scheme of covert satellite signal transmission is proposed. On the satellite, the time-frequency domain characteristics of the original service signal are hidden by multiplying the service signal to be transmitted with the specially designed non-constant envelope masking signal. At the authorized ground station, the masking signal replica is used for cross-correlation time delay estimation and de-masking, so as to restore the original service signal. This scheme has the advantages of no increase in transmission power consumption, low complexity of on-board masking operation and strong transmission security. In addition, the covert performance of the scheme is analyzed through quantitative evaluation indexes such as processing loss and mutual information. Simulation results show that the masking scheme can achieve good masking effect in time-frequency domain. The mutual information between the masked signal and the original service signal shows that the correlation between the masked signal and the original service signal is very weak, and the communication characteristic of the original service signal has been basically covered. Under the condition that the ratio of the masking signal to the original service signal bandwidth is not less than 0.3, and the signal-to-noise ratio is not less than –4 dB, the processing loss of authorized ground station de-masking processing can be controlled within 1 dB, which has good practical value.