[sandip_aqua]

Dear All,
This my first post on GPS forum. I have started working on GPS data processing recently.

I have calculated ECEF coordinated data (i.e. x.y,z) of a GPS satellite from respective GPS ephemeris data which is extracted from navigation message data from RINEX file.

Regarding the same I have few queries. These are listed below;

Example: 2 hr Navigation message data with sampling rate of 10 sec is given.

Q.1. How to recognize from the RINEX navigation message data that at what point the first sample is finished and second sample is started ?

Q.2. How to know that how many satellites are visible at that time from RINEX file?

Q.3. How to calculate the GPS receiver position from ECEF data?

with these initial questions I am requesting you all to please look in to the matter and guide me in this regards

kind regards
Sandip

[typer]

I don't know how to do this, but there is open source software that can do it for you, like rtklib or gogps java. Maybe if you look at their code you can figure it out?