Y.N. Boldenkov, I.V. Lipa, A.Y. Shatilov
All modernized satellite navigation systems will utilize signals with BOC(n,m) modulation. This kind of signals have a significant drawback – multi-modal correlation function. This issue leads to some problems with signal acquisition. A modification of a known BPSK-like technique of non-ambiguous BOC(n, m) signal acquisition is provided in this article.
One of the most significant problem in signal acquisition nowadays is sensitivity improvement. It is unreasonable for some suggestions to have long coherent integration time. That’s why non-coherent integration is widely used. Non-coherent integration leads to additional squaring losses with respect to coherent integration. Special technique named «Post-detection differential scheme» is known to improve non-coherent integration performance. It is based on the fact that noise samples from different moments are uncorrelated.
Another way of non-coherent integration is considered in the article. BOC(n, m) signals have a two-component spectrum with lower and upper lobes. BPSK-like technique is based on separate processing of these lobes. While noise parts of both side lobes are uncorrelated, signal parts are strictly dependent according to signal structure. This fact gave a way to make another technique of non-coherent integration with the same characteristic, as «Post-detection differential scheme», but for simultaneous samples for correlators tuned for each lobe.