Abstract:

The model of combined GPS/GLONASS static relative positioning is introduced. The ambiguities of double difference GLONASS observations are expressed as the single difference ambiguity of reference satellite and double difference ambiguities. It is proved via error analysis that the single difference ambiguity of GLONASS can be solved as a real number, while the double difference ambiguities must be solved as integer parameters. And the weights of GPS and GLONASS observations are determined by using Helmert variance component estimation. The numerical examples with real GPS/GLONASS observations indicate that the accuracy of combined GPS/GLONASS positioning is better than that of a single system positioning. Especially, compared with the single GLONASS system, the accuracy is greatly improved, and compared with single the GPS system, the improvement is about 10% in the case of single epoch baseline solution. When available satellites of a single system are less than four, combined GPS/GLONASS positioning has more advantages.

Key words: GPS/GLONASS, relative positioning, ambiguity resolution, variance component estimation