One alternative could be to run it on a GPS simulator, and collect the NMEA data, though you would have wait for the 5 hours.n

Try AGI STK (http://www.agi.com/products/). I'm doing some DOP calculations for my Master thesis in this software. There are many tutorial videos and instructional publications that can get you going. Also, there is a free version that I think is sufficient for your needs.

GPS Matlab Toolbox by l3nav

http://www.l3nav.com/

http://www.mathworks.it/products/connections/product_detail/product_35386.html

i think scientific software such as GAMIT or Berneas can help you on this issue

A Thesis is defined in K.N.TOOSI university that the objective is to produce a program to calculate constellation measures in terms of baselines such as success rate and dops. contact [email protected] who is Dr. M. Hossainali, the corresponding professor. He may help you.

From what I understand you want to find optimal DOP within specific corridor. I suggest to simplify problem to the worse point on the track and observe constellation there for time specified to determine worst conditions.

In case of 50km stretch you can define points every 10km and again check for worst conditions at each point.

One thing to consider is:

In case of land observation: any obstructions which might limit sky visibility (for ex assume 25deg cut off angle)

In case of naval observations: water reflection and extensive banking (consider 15deg cut off angle?)

Trimble website suggested before would then be sufficient.

What we have developed at K.N.Toosi University is a Matlab toolbox which uses double difference equations for computing DOPs as well as some other parameters such as success rate (which can help derived the minimal required time for making the measurements). The advantage of this toolbox to similar commercial software is that it really works in network mode. In network mode, commercial softwares estimate the planning parameters for each station separately and then compute a mean for that parameter within the network of interest. In contrary to commercial softwares this toolbox is based on double difference equations and therefore conforms to the processing procedure of GPS measurements in relative positioning mode. It also directly estimates the required measurement time. This is based on the sky view of the GPS stations which is provided to this toolbox.

1. Download "ORBITRON" (free s/w tool available @http://www.stoff.pl/) and run it.

2. Update TLE files for operational GPS from http://celestrak.com/NORAD/elements/gps-ops.txt

3. Use simulation utility of orbitron with your updated location --> jump intervals of time to simulate the GPS constellation for future times (or location)

4. For a suitable point of time (may be each 30 minutes), select a GPS satellite on the right hand bottom "skyplot" window

5. When a satellite is selected - click on "ROTOR/RADIO" tab --> you can note the elevation and azimuth of each satellite --> Note down the elevation and azimuth of all GPS satellites (above the cut off mask) for this particular point of time.

6. You can use any DOP calculating s/w for each point (of time OR location)

7. We have developed a program to do the same that calculates PDOP values fairly accurately from elevation and azimuth of satellites, please let me know if you need support.

Some of you did not understand my question. How to use the software to plan constellation teach at universities. This is a measurement at one point with terrain obstracles. Trimble Planning and other software wchich some of You recomended can be useful.

Referring to the interesting answers Rinesh solution with GPS simulator is OK, even taking into account the terrain model. But the question was about the planning which means that, for example after 30 km I would like to stop the measurements for a few minutes because the value of PDOP is to high. This funciton (planning, not stopping) cannot be realised in GPS simulators .

brgs

cezar