Toward Instantaneous Network-Based Real-Time Kinematic GPS over 100 km Distance

ABSTRACT: Instantaneous (single-epoch) ambiguity resolution may not always be possible because of the increasing noise and lack of sufficient redundancy to verify the integer selection in long-range real-time kinematic (RTK) GPS positioning. The algorithm proposed here is based on a single-baseline solution aided by double-difference (DD) ionospheric delay from the previous epoch (up to 60 s latency in DD ionospheric delay can be accepted), which supports the ambiguity resolution and provides a quality instantaneous kinematic position over long distances. However, obtaining the initial DD ionospheric delay requires atmospheric corrections provided by the reference network and some accumulation at the beginning of the session—i.e., on-the-fly (OTF) initialization is needed. Afterwards, instantaneous RTK positioning is assured. In this paper, a feasibility test of instantaneous real-time rover positioning is presented, and the effect of the latency of the DD ionospheric corrections on the instantaneous ambiguity resolution in long-range RTK is investigated. The positioning accuracy achieved in the tests, expressed as the differences between the resultant coordinates and the known “true” coordinates, is at millimeter-level accuracy for the horizontal components and centimeter-level for the vertical one for baselines over 100 km long.

[1]  J. Kusche,et al.  Regularization of geopotential determination from satellite data by variance components , 2002 .

[2]  Pawel Wielgosz,et al.  Analysis of the Network Geometry and Station Separation for Network-Based RTK , 2004 .

[3]  P. Teunissen.  A new method for fast carrier phase ambiguity estimation , 1994, Proceedings of 1994 IEEE Position, Location and Navigation Symposium - PLANS'94.

[4]  Benjamin Remondi.  High Accuracy-Nationwide Differential Global Positioning System Test and Analysis Phase II Report , 2005 .

[5]  Pawel Wielgosz,et al.  Network Approach to Precise GPS Navigation , 2003 .

[6]  Christian Rocken,et al.  Obtaining single path phase delays from GPS double differences , 2000 .

[7]  Peter Teunissen,et al.  A comparison of TCAR, CIR and LAMBDA GNSS ambiguity resolution , 2003 .

[8]  Pawel Wielgosz,et al.  Free Net Adjustment in Multi Reference Stations Approach for Instantaneous RTK , 2003 .

[9]  I. Kashani.  Application of Generalized approach to Datum Transformation between Local Classical and Satellite-based Geodetic Networks , 2006 .

[10]  Jinling Wang,et al.  A discrimination test procedure for ambiguity resolution on-the-fly , 1998 .

[11]  Charles C. Counselman,et al.  Method of resolving radio phase ambiguity in satellite orbit determination , 1989 .

[12]  Yehuda Bock,et al.  Wireless Instantaneous Network RTK: Positioning and Navigation , 2003 .

[13]  H. Schmid,et al.  A Generalized Least Squares Solution Hybrid Measuring Systems , 1965 .

[14]  P. Teunissen,et al.  Rank-defect integer estimation and phase-only modernized GPS ambiguity resolution , 2003 .