Due: November 4, 2003

Assignment

Go back to your code for Lab 7 (GPS Errors 2). Copy it.

Instead of using "my orbits" we will now be using "your orbits." Ideally, we would just use your orbits lab code, but we need to make a slight change to use the orbit at transmit time, rather than receive time. This is a little tricky, so I am going to give you the code to do this.

Software Description

• Define the GPS constants, including those that will be needed for the ionosphere free observables.
• Read the RINEX header of the given file.
• Convert the receiver coordinates into latitude, longitude, and height.
• Read in the receiver clock corrections for the 660 epochs in your data file.
• Read in the observations. For each observation:
  1. Calculate R_L3
  2. Calculate its satellite_clock correction
  3. Calculate the geometric range at receive time (using Lab 8.)
  4. Calculate the geometric range at transmit time using my code. This code will also return the relativity correction.
  5. Calculate elevation angle (it won't matter if you use the receive or the transmit satellite coordinates).
  6. Calculate its troposphere correction, using the model from class.
  7. Calculate R_L3 - GR_receive + satellite_clk - receiver_clk - troposphere - relativity.
  8. Calculate R_L3 - GR_transmit + satellite_clk - receiver_clk - troposphere - relativity.

Plot as a function of time (hours since midnite):

• the relativity correction.
• the troposphere correction.
• R_L3 - GR_receive + satellite_clk - receiver_clk - troposphere - relativity.
• R_L3 - GR_transmit + satellite_clk - receiver_clk - troposphere - relativity.

Plots, software. Five bonus points for (correct) ideas as to why things begin to deteriorate around hour 3.