反射波が支配的な状況下でのマルチパス誤差低減

概要

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Multipath is one of the major error sources in Global Positioning System (GPS) measurements. Separation from reflection surfaces is the most effective way to reduce the multipath errors, but it is not always possible. Currently, many multipath mitigation algorithms which modify tracking loop discriminators have been invented to reduce the effect due to the multipath signals arriving after the corresponding line-of-sight signal. These techniques, however, are not applicable when multipath signals are stronger than the direct signal. This paper proposes a new multipath mitigation technique under such conditions. Instead of finding the point to maximize the correlation power using any code discriminator, the proposed algorithm detects the rising edge of the correlation triangle of the line-of-sight signal which always arrives earlier than the multipath signals. In order to evaluate this new technique, a Signal Quality Monitoring (SQM) receiver was used to collect correlation curves during code tracking. The post-processing results showed that the positioning errors caused by stronger multipath signals were effectively removed by the proposed mitigation algorithm.
社団法人日本航海学会の論文
2008-03-25