A new positioning method by two GNSS satellites and relative position constraint

Global Navigation Satellite System (GNSS) provides consistently accurate position solutions when four or more GNSS satellites are observable. However, this condition is usually not satisfied under harsh conditions such as urban canyon, tunnels and other special application environment, and this case will lead to degradation of positioning precision or infeasibility of the positioning algorithm. This paper presents a novel method to provide reliable position solution with only two visible satellites. We propose to utilize the relative position change during a short period as a constrain condition to estimate the absolute position of GNSS receiver. The simulation experiment has been carried out and the result demonstrates that the proposed method is effective in improving the positioning performance.