Chapter 57 A Fast Positioning Method for Hot Start in GNSS Receiver

摘要

Time to First Fix (TTFF) is an important parameter used for the evaluation of the performance of a GNSS receiver. For most mass market applications, it is attractive that the GNSS receiver has a first position fix within few seconds, while providing a relatively accurate first fix output. A short TTFF can be obtained by using Akopian's iterative estimation of satellite time of transmissions with a least-square method. The position computation needs at least five satellites in Akopian's method. However, several factors (such as 1-ms fuzziness and mis-acquisition, etc.) limit the usage of Akopian's method. This paper proposes the corresponding schemes to solve these problems and give a reliable and feasible fast positioning method considering both TTFF and the accuracy.