Estimation of Receiver GPS-GLONASS Bias

In order to simultaneously process GPS and GLONASS data from different receivers it was necessary to estimate for each GPS-GLONASS combined receiver an inter-system bias that models the different signal path or processing delay within the antenna, cable, amplifier or receiver for the GLONASS and GPS signals.

A perturbation in the estimation of these biases is the difficulty in establishing absolute GPS and GLONASS time references due to errors caused by SA, broadcast message or our own IGS clock estimation.

After removing the common variability due to the error in the estimation of the absolute GPS and GLONASS times the biases are in most cases stable and depend mostly on the type of receiver:

• Z-18's receivers have values with offsets between -55 to 40 ns and day to day variations in the range of 1 to 3 ns.
• JPS Legacy receivers have lately stabilized at about -140 ns.
• The ESA/ISN receivers has a bias around -980 ns with day to day variations of about 1 ns.

[ nng home | gps pages | gps tdaf | data collection | data analysis | ionosphere ]