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TitleAnalysis of GPS-DCM clock corrections in support of 1Hz PPP-AR applications
AuthorKamali, O K; Lahaye, F L
SourceProceedings of the 2019 International Technical Meeting of The Institute of Navigation; 2019 p. 568-576,
Alt SeriesNatural Resources Canada, Contribution Series 20180236
PublisherInstitute of Navigation
MeetingThe Institute of Navigation (ION), International technical meeting (ITM) 2019; Reston, VA; US; January 28-31, 2019
Mediaon-line; digital
File formathtml
Subjectsremote sensing
ProgramGeodetic Survey, Canadian Spatial Reference System
Released2019 01 28
AbstractDecoupled-Clock Model (DCM) improves the accuracy of Precise Point Positioning (PPP) by enabling Ambiguity Resolution (AR). Clock and bias corrections are typically estimated at 30-seconds rate to reduce the computation time. However, high rate PPP-AR applications, typically use 1 Hz tracking data, and ideally require 1-s clock corrections. The quality of the interpolated DCM corrections are evaluated by comparing the interpolation error of DCM clocks and biases of GPS satellites over different intervals. It is showed that for short-term intervals i.e. from 5 to 30 seconds, the RMS error of DCM clock grows by 0.5, 2.5, 2.8, 3.2 and 5.6 ps per 5-second increments of the interpolation interval respectively for Blocks IIFRb, IIA, IIR, IIR-M and IIF-Cs. The RMS interpolation error of DCM biases were dominated by pseudo-range noise where the noise level of ionosphere-free code/phase biases were about ~4.2 times of the noise level of wide lane biases. Allan Deviation (ADEV) of DCM corrections are then estimated to evaluate the short-term stability and to characterize the random behaviour of these corrections within different intervals. This allows the high-rate PPP-AR users to introduce observation weights based on the expected clock instabilities and interpolation errors. The deterioration of the horizontal PPP-AR on kinematic mode are compared by applying DCM corrections at the rate of 5, 10…30 seconds. In kinematic PPP-AR, at least 60 minutes of GPS observations were required to reach 80% AR success-rate that allow for centimeter-level horizontal precisions. Using 5- and 30- second DCM corrections increased the RMS error of PPP-AR by respectively 1, and 6 mm that represents 10% and 60% deterioration comparing to 1-second solutions.
Summary(Plain Language Summary, not published)
Currently NRCan provides rigorous GPS corrections to obtain consistent cm-level positioning in Canadian Spatial Reference System. Clients with high-rate applications ideally require full 1-second corrections. However, corrections are conventionally estimated at a 30-second rate to reduce the computation time. This reduction of the rate can deteriorate the positioning precision of clients. The information on the stability of corrections is necessary for users to satisfy their positioning precision requirements. This investigation presents whether a reduced sampling rate of corrections is sufficient to reach the equivalent of full 1-second correction set.