Usage of Terrestrial DGPS Services for High Precision Aircraft Applications

摘要

Commercial aviation and general aviation are two of thernmajor users of GPS positioning and navigation. But forrnsafety critical reasons they require high accuracy,rnavailability and reliability of the position information.rnHence during the last years wide area augmentationrnsystems like WAAS, EGNOS and MSAS have beenrndeveloped.rnNevertheless they are still under development and willrnreach operational capability only in a few years.rnBut many airborne applications require a high precisionrnpositioning and navigation nowadays. Especially users ofrnspecial mission aircrafts (e.g. meteorological airdatarnmeasurements, airborne gravimetry, airbornernphotogrammetry, instrumentation flight testing andrncertification etc.) and helicopters demand a precisernpositioning. Rescue helicopters use navigation systems tornlocalize accidents or for precision approaches on medicalrncenters. Search and Rescue helicopters (SAR) oftenrnoperate under non-visual meteorological conditions orrnduring nights. Therefore the pilot needs every additionalrninformation he can get about his position.rnMany countries have already set-up terrestrial DGPSrnservices, which provide different levels of accuracy. Mostrnof these services broadcast correction data in RTCMrnformat. It ranges from RTCM Type 1 messages for aspects of broadcast coverage, availability and accuracyrnduring flights will be addressed. In addition results fromrnflight trials will be presented. A special focus is taken onrnthe usage of a DGPS reference station system for RTKrncarrier-phase solution.