CODE contribution to the IGS Repro3: Status and assessment of the reprocessing products for integer-ambiguity precise point positioning.

Abstract:

CODE, the Center for Orbit Determination in Europe, is one of the global analysis centers (AC) of the International GNSS Service (IGS, where GNSS stands for Global Navigation Satellite Systems). As an AC CODE provides, among others, satellite orbits, Earth rotation parameters, satellite clock corrections, and observable-specific code and phase signal biases (OSB) to the community enabling integer-fixed precise point positioning (IPPP) – even for ultra-highrate applications.

In addition to the traditional IGS product lines with different latencies (final, rapid, and ultra-rapid) CODE also contributes to the reprocessing campaign Repro3 of the IGS for the next realization of the International Terrestrial Reference Frame (ITRF). For the reprocessing GPS, GLONASS, and Galileo are processed estimating, among others, their orbits, integer-fixed satellite clock correction, and the corresponding phase and code biases allowing the user to perform IPPP solutions (for GPS and Galileo). CODE follows the so called common clock and OSB approach (CC-OSB) for the IPPP enabling products.

The satellite clock corrections and OSBs are estimated using a 5 minute sampling which allows to estimate ambiguity resolved clocks and daily OSB values for the IPPP. In addition to the 5 minute clock product, CODE also provide phase based 30 second and even 5 second phase-interpolated clock corrections which have the same characteristics as the 5 minute sampled clocks – allowing for PPP ambiguity resolution (PPP-AR). The 5 second densification is in particular important for ultra-highrate applications (like kinematic LEO orbit determination) with 1 second sampled data as the clocks for GPS are not stable enough for linear interpolation over 30 seconds.

In this study we focus mainly on the PPP ambiguity resolution of our clock estimation and assess the quality of our integer-fixed clock products. In addition, we will give a brief overview on our PPP-AR strategy used during the clock estimation and how the CC-OSB clock products can be used for IPPP purposes on the user side.