DORIS-DIODE: two-years results of the first European Navigator Original Research Article

The DORIS system was developed to support high accuracy orbit determination and beacon positioning. For the first time, thanks to DIODE, the SPOT-4 satellite orbit is determined in real time on-board with an accuracy of 3–5 meters. Two year DIODE/SPOT-4 monitoring shows that this Navigator has been operational 99.4 % of the time with a few meters accuracy, even through maneuvers. An improved version of DIODE will be loaded on board SPOT-4 next year and will fly, including new upgrades, on board Jason-1, ENVISAT and SPOT-5. Simulations performed using TOPEX/POSEIDON DORIS measurements show that a sub-meter accuracy will be reached with Jason-1.