The Integrity Monitoring Methods for Pseudolite and Satellite Navigation System

摘要

The modern positioning systems are able to determine the position with high frequency and with very high accuracy, but mostly these systems and used methods aren't usable in safety related applications. It needs the safety analyse of the system to be performed. Recently, the meaning of the satellite navigation systems (GNSS) increases. But, for the applications, with high safety level requirement, the satellite navigation in itself should not be sufficient. In this case, the positioning system must be completed with next systems - most often it is the system of inertial sensors. Besides, it's possible to use also system of ground transmitters of satellite signal - pseudolites (PL's). This system is "ground equivalent" to satellites system, only signal transmitters are not on the orbits, but they are on the fixed point on the ground. It have certain advantages compared with satellites system - especially warranted availability of the signal in critical area and accurately defined and fixed position of trasmitters. The safety analysis method will be also analogic to safety analysis of the self satellite navigation, but it must conform to all specifics. The subject of this paper will be just safety analysis, namely integrity monitoring of the PL's system and its combination with GNSS. The safety applications based on satellites and PL's system can be designed in two ways. The direct combination of signals from all transmitters (satellites and also pseudolites) - one solution of the position and integrity in one receiver or two independent channels - one for PL's system and the second for GNSS and combination of both independent solutions.