GPS doppler processing for precise positioning in dynamic applications

Abstract

A doppler processing technique for smoothing the GPS code-phase measurements is presented. It is shown that this technique can enhance the resolution of C/A pseudo-range measurements to better than 1 centimeter. Data is presented to show that it is possible to obtain position fixes with an runs scatter of a few centimeters from the C/A code. Although the presented technique is applicable to both static and dynamic situations, it is particularly attractive in dynamic applications, where position averaging cannot be performed. This is shown to be a key factor in obtaining sub-meter differential accuracy in low dynamic applications. The interchannel biases in multichannel receivers are also discussed. It is shown how the advantages of multichannel design can be retained without suffering from this effect. The above techniques are implemented in the TRIMBLE 4000A LOCATORs and results are presented in this paper.