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Project Highlights 2005 - GPS Measurement Corrections for Geophysicists

GPS Measurement Corrections for Geophysicists: A Calibration Procedure for Pseudorange Data

  • Principal Investigator (PI): Kristine Larson & Kevin Choi - University of Colorado
  • UNAVCO Engineers: Victoria Andreatta, Warren Gallahar
  • Dates: August 2004 - June 2006
  • Location: Boulder, Colorado

A Thermotron environmental test chamber was recently purchased providing the capability to test system components in a controlled environment at extreme temperatures (-70 deg C - 70 deg C). The chamber was primarily purchased to support the 'GPS Measurement Corrections for Geophysicists' experiment being conducted at the UNAVCO Facility by Kristine Larson and Kevin Choi. This experiment is a zero baseline experiment to measure and study pseudorange biases (C1-P1, P1-P2) between different manufacturers of high precision GPS receivers.

GPS receiver manufacturers have responded to restrictions on the GPS signal structure in different ways. The impact of their decisions means that different GPS observable combinations are available to the geophysics community depending on which receiver it purchases. Based on analysis of global tracking data, the L1 pseudoranges are known to be biased with respect to each other. The Department of Defense will shortly add a third frequency and a second civilian code. There will be biases associated with these changes and a calibration procedure is needed. The goal is to develop an accurate method for calculating and accouting for these differences.

Last modified: Sunday, 11-May-2014 18:01:25 UTC

 

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