A diversity technique of anti-multipath based on STBC for pseudolite systems

In the design of indoor high-precision positioning systems, the multipath effect is the main problem impacting the performance of the pseudolite positioning system. For the indoor propagate environment, multipath fading serious, signal losing frequently, signal to noise ratio cutting down. In order to reduce the multipath effect and improve the relevant capture characteristics of the receiving loop, we presents a technical scheme adding STBC (Space-time Block Coding) to conventional pseudolite systems. Therefore the dual-transmitting and single-receiving antenna (2Tx, 1Rx) is adopted in this scheme. Meanwhile the space-time encoding based on STBC is used at the transmitter, and channel frequency estimating, space time decoding based on MLD (Maximum Likelihood Decoding) and EGC (Equal-Gain Combining) are used at the receiver. The simulation results show that the scheme can reduce the impacts of multipath effect and increase the SNR (Signal-to-Noise Ratio) of received signals, so as to improve the positioning accuracy of the pseudolite receiver.