How to read obs data?

[qzmp69375 (聖元)]

I’m trobuled in read obs obs data.I want to know every numbers means to study gnss?

finally,anyone can introduced some books or thesis about gnss or post processed kinematics?

[kseniia.suzdaltseva]

Hi @qzmp69375 , and welcome to our community forum!

Data records in RINEX .obs files include the following content:

The first line is the epoch. It shows the date and time of the record in yyyymmdd hhmmss format.

In the first column:

• The letter shows the satellite system (G for GPS, R for GLONASS, E for Galileo, etc.).

• The value is the number of a particular satellite.

Each line contains several variables for the specified satellite. They go in the following order:

• C = pseudorange, which is the distance from the receiver antenna to the satellite antenna, including receiver and satellite clock offsets.

• L = career phase. It’s the difference between the phase of the receiver oscillator and the signal received from the satellite + the number of cycles at the initial start of the tracking phase.

• D = doppler, which stands for a change of frequency due to the Doppler effect. The sign of the value is positive for approaching satellites.

• S = signal strength or Signal-to-Noise Ratio (SNR). It’s the value that compares the level of the desired signal to the level of background noise. The great value for L1 frequency starts from 35-40.