Blind despreading of BOC signal in the radio-navigation satellite system

Binary Offset Carrier (BOC) modulation is considered for the modernized military GPS and the European Navigation System Galileo. The way of BOC signal blind despreading can be deducted from the way of BPSK. Taking the advantage of the carrier correlation of civil and military signals, carrier synchronization can be got before chip synchronization, so that the baseband signal is got which is easier to estimate the PN code. Noticing the frequency dual sides of BOC signals, the upper side band and lower side band can be separated and combined together to raise the signal-to-noise ratio for non-coherent integration. At the same time, signal can be down sampled to the rate of PN code for the relationship between the subcarrier and the PN code, that is to say, the PN code can be estimated directly ignoring the subcarrier, which simplifies hardware implementation. Experiment and simulation results show that this proposed “dual side bands combine-downsample-eigenanalysis” arithmetic can provide a good estimation to BOC signal, even in low SNR.