Sea state sensing with single frequency GPS receiver

Bi-static remote sensing with GPS signal (direct and reflect signals) has supported some researches in soil moisture measuring, sea state estimating and sea altimetry monitoring. In these researches the special designed receivers are generally required, such as the "delay-mapping" GPS receiver or open loop differential real-time receiver, because they can find the characteristics of the reflected electromagnetic wave affected by the object. Now the commercial single frequency GPS receiver becomes more lighter, smaller and lower power, it is potentially capable of sea remote sensing. However it is ignored. In this paper, a ground based GPS-R technology with single frequency receiver is introduced. The technology is based on both the scatter theory from the rough surface and the GPS double difference theory of carrier phase. This paper describes the GPS-R instrument, introduces the basic method and shows the result of GPS-R experiments on bridge. These results provide good initial conditions for widespread sea state monitoring if using GPS-R receiver network . this paper also discusses the results under the influence of the satellite elevation and single difference .