Geodesy with the Global Positioning System

EESC G9945 Section 2

Spring Term 2013

Term Project Subgoal 4 Information

Due date: 3 May 2013 [Revised]

Background

The goal is to combine the RINEX GPS data and the orbit information (including the satellite clocks) to perform a clock solution. You will use the pseudorange models presented in class.

What your code should do

You will use the ionospheric-free linear combination of the pseduoranges in the RINEX file we have been using to perform an iterative non-linear least-squares fit to solve for the cartesian site coordinates and the receiver clock error at each epoch for which there are data. Use all data; don't eliminate data based on elevation angle. Assume a starting location of (0,0,0) for the first iteration. Assume equal weights on the LC pseudorange of 10 m. Assume a zero value for the neutral atmospheric propagation delay. Iterate until your results converge at the 0.01-m-level.

What to send me:

1. A text file with the estimated coordinates (including uncertainties) and RMS residual for each iteration
2. A plot of the residuals as a function of elevation angle
3. A plot of the clock error vs. epoch for the first 1 hour of the data file (i.e., 0 through 1 UT)

E-mail the results of your program by 5 PM on the due date.