Research On Signal Multiplexing Strategy And Compatibility Of Compass Navigation Satellite System

To provide more accurate and diverse services, more and more navigation signals are planning to be broadcasted. Several signals need to be multiplexed into one signal with constant envelope to reduce the number of high-power amplifiers on satellites. Also, the limited resources of navigation signal spectrum result to the overlap between different signals. Then analyzing the signal interference due to spectrum overlap and the effects of high power amplifier non-linear distortion to compatibility becomes a hotspot problem.The thesis is divided into two main parts. Main contents are as follows:(1) The implementation principles and multiplexing efficiency of current multiplexing techniques in satellite navigation systems were analyzed. For B1-band signals, Interplex and major voting were adopted with the data and pilot channel power 50/50 and 25/75. The multiplexing efficiency was discussed for different shemes and reasonable multiplexing solution was given. For B2-band signals, ACE-BOC modulation was proposed and the modulated signal was analyzed from power spectral density, Gabor band width, code tracking accuracy, multipath error performance and anti-jam performance. For B3-band signals, due to the high rate of navigation data, the power of data channel couldn’t be too small for demodulation. So with the power allocation of data and pilot channel 50/50, Interplex and major voting were adopted for signals multiplexing and reasonable multiplexing scheme was given. Then established the relationship between multiplexing efficiency and code tracking and evaluated the impact of multiplexing loss on code tracking accruracy.(2) Established a model of navigation signals compatibility assessment, and given evaluation parameters and process. Then evaluated the compatibility of COMPASS, GPS and Galileo navigation signals, including SSC, CT_SSC and degradation of effective carrier-to-noise ratio, and proposed some techniques like ACE-BOC and MSK modulation to improve it.(3) Analyzed the reasons of high power amplifier non-linear effection and established a non-linear model. Through equivalent the transmitter and receiver model to baseband, the impact of filter bandwidth and high power amplifier non-linear effects on navigation signals was simulated and analyzed. Introduced the adjacent channel power ratio ACPR, and analyzed the power leakage problem and compatibility between adjacent channel signals caused by the impact of the power amplifier nonlinear distortion.