KINEMATIC AMBIGUITY RESOLUTION WITH HIGH-PRECISION C/A CODE RECEIVER

On-the-fly resolution of carrier phase ambiguities, which is the key to centimeter-level accuracy in differential kinematic GPS positioning, is investigated using a high-precision, single-frequency 10-channel, C/A code receiver. The major characteristic of this C/A code receiver is its narrow correlation spacing, which improves code-measuring accuracy to 10 cm and reduces code multipath interference. The high accuracy of the code enables the user to reduce the search area containing the correct integer-ambiguity solution. The principles of the least-squares search procedure used herein to obtain the correct ambiguity solution are described. Kinematic test results for land are presented for the cases of a benign multipath environment and a comparatively high multipath environment. For the benign multipath case, the correct ambiguities are found within 1-3 min, with a high success rate, under a relatively good six-satellite geometry (GDOP almost-equal-to 3) and a short monitor-remote separation (<5 km). In the presence of carrier phase multipath caused by nearby trees, however, the success rate decreases to less than 50% and the correct ambiguity solutions are found only after a significantly longer observation period.