Font Size: a A A

High integrity carrier phase navigation using multiple civil GPS signals

Posted on:2001-09-11Degree:Ph.DType:Thesis
University:Stanford UniversityCandidate:Jung, JaewooFull Text:PDF
GTID:2468390014453327Subject:Engineering
Abstract/Summary:
A navigation system should guide users to their destinations accurately and reliably. Among the many available navigation aids, the Global Positioning System stands out due to its unique capabilities. It is a satellite-based navigation system which covers the entire Earth with horizontal accuracy of 20 meters for stand alone civil users.; Today, the GPS provides only one civil signal, but two more signals will be available in the near future. GPS will provide a second signal at 1227.60 MHz (L2) and a third signal at 1176.45 MHz (Lc), in addition to the current signal at 1575.42 MHz (L1). The focus of this thesis is exploring the possibility of using beat frequencies of these signals to provide navigation aid to users with high accuracy and integrity.; To achieve high accuracy, the carrier phase differential GPS is used. The integer ambiguity is resolved using the Cascade Integer Resolution (CIR), which is defined in this thesis. The CIR is an instantaneous, geometry-free integer resolution method utilizing beat frequencies of GPS signals. To insure high integrity, the probability of incorrect integer ambiguity resolution using the CIR is analyzed. The CIR can immediately resolve the Lc integer ambiguity up to 2.4 km from the reference receiver, the Widelane (L1-L2) integer ambiguity up to 22 km, and the Extra Widelane (L2-Lc) integer ambiguity from there on, with probability of incorrect integer resolution of 10−4 .; The optimal use of algebraic combinations of multiple GPS signals are also investigated in this thesis. Finally, the gradient of residual differential ionospheric error is estimated to stimated to increase performance of the CIR.
Keywords/Search Tags:GPS, Navigation, CIR, Using, Signal, Integer ambiguity, Civil, Integrity
Related items