A Fast Positioning Method of Navigation Receiver Assisted by Doppler Information

In order to shorten the time to first fix (TTFF) of the satellite receiver, a fast positioning method using both carrier and pseudo code observation is proposed. First, use the Doppler information acquired by the carrier tracking loop to reduce the a priori time accuracy to 100 s. Then, use the code phase acquired by pseudo-code tracking loop, and use the five-state equation to solve the receiver position. In this way, positioning can be achieved before frame synchronization and bit synchronization. Numerical simulation and test results show that positioning can be achieved within 1s through Beidou/GPS dual system in the global or BeiDou alone in the Asia-Pacific region, when the a priori position accuracy is less than 10 km and the a priori time accuracy is less than 2 h.