Pseudolite Cellular Network in Urban and Its High Precision Positioning Technology

GNSS in urban was Easy to cause signal shielding effect, it is difficult to provide seamless positioning service, Firstly, the positioning cellular networks based on pseudolites was Proposed in the paper, the system composition, working principle and compatible signal was introduced, the innovation is put forward that the closed loop time synchronization technology based on the pseudolites navigation signal transmission network, and the digital time synchronizer was developed. The experimental tests was showed that time synchronization accuracy between pseudolites were better than 2 ns; Secondly, three network topology of pseudolite was put forward, such as star, ring and cellular structure. According to the principle of service area was biggest, quantity of pseudolites was less, GDOP and HDOP was least, it was proved that a kind of center-distribution cellular networks was optimal by the simulation analysis. Finally, The positioning performance testbed of Ye San Po for pseudolite cellular networks was build, it was showed that the pseudorange positioning accuracy was better than 5 m, carrier phase positioning accuracy was better than 20 cm, then the pseudolite cellular network could satisfy the high-precision positioning requirement of the urban.