The Null method applied to GNSS three-carrier phase ambiguity resolution

The Null method is a technique to fix the ambiguity in L1 phase measurements of the global positioning system (GPS). The method is adapted to new global navigation satellite systems (GNSS) which offer phase measurements at three frequencies. In order to validate the efficiency of the adapted method, results obtained using a software simulator and an emulator are presented. The results are then compared to those obtained with the least-squares ambiguity decorrelation adjustment (LAMBDA) method. Good performance of the Null method in new GNSS systems is shown.Acknowledgments. The measurements used were provided by the European Space Agency, and were generated by Spectra Precision Terrasat under contract No. 12.406/77/NL/DS. The authors thank Maria Belmontes Rivas for her comments and the reviewers for their suggestions.