AbstractThe DORIS instrument on Jason-2 is the first of a new generation. The satellite receivers have now seven simultaneous measurement channels, with synchronous dual frequency phase and pseudo-range measurements. These measurements are now described in a similar manner as GPS measurements and an extension of the RINEX 3.0 format has been defined for DORIS. Data are available to users with a shorter latency.This work describes the pseudo-range and phase observedon Jason-2 (noise, interruptions, cycle slip occurrences). An important part of the measurements is performed at low elevations (more than 50% are below 20° elevation). We show that a 2GHz cycle slip occurs frequently at maximal elevation of a pass (below 30°).A peculiarity of the DORIS system is that the frequency ratio is close to 5 (the frequencies are close to 2GHz and 400MHz). The ionosphere-free combination of the phase measurements is very close to an integer combination with small integer coefficients (5 for the 2GHz and 1 for the 400MHz data). This makes cycle slip reconstruction possible, but has also drawbacks, as some cycle slip combinations are difficult to detect. A strategy for detection and reconstructions of the phase cycle slips is proposed.The DORIS system uses a polynomial model for the on board oscillator, in order to synchronize all measurement epochs to TAI. In the preceding instruments, this synchronization was performed by the ground segment, and the result was stored in the user measurement file. Using the pseudo-range measurements of the reference time beacons given in the RINEX files, it is now possible for the user to identify the on board clock offset.The phase measurements residuals obtained using a precise Jason-2 orbit are then analyzed. Antenna phase maps are constructed to represent some of the systematic errors observed in the residuals. It is shown that an important limitation in the analysis is the effect of the clock errors during a visibility pass. An example is shown on the Fairbanks phase residuals.Finally, Jason-2 preliminary DORIS orbits using directly the phase information are presented for cycles 1–17 (July–December 2008). Although phase solutions have not been specifically adapted to overcome clock errors effects, they prove to have an equivalent performance as the standard Doppler orbits, with a better observability.
Jason-2 DORIS phase measurement processing
Advances in Space Research ; 45 , 12 ; 1441-1454
2009-12-03
14 pages
Article (Journal)
Electronic Resource
English
DORIS , GPS , Antenna phase map , Phase , Cycle slip , Orbit determination
Jason-2 DORIS phase measurement processing
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