Assessments of Satellite Navigation Signal Usability for Aviation Applications
In aviation, the use of GNSS signals for en-route navigation and precision landings will gradually replace conventional navigation aids. Complementing Satellite Based Augmentation Systems (SBAS), Ground Based Augmentation Systems (GBAS) will enable precise approach and landing also down to the lowest visibility conditions (CAT-III), making it a viable successor to the Instrument Landing System (ILS). A GBAS can improve airspace design flexibility, fuel consumption and emissions and contribute to the optimization of airport capacity planning.
With its unique background as the German operator of the European Galileo navigation satellites and a certified Air Navigation Service Provider (ANSP), DLR GfR is the perfect partner during all phases of GBAS planning, implementation and operation.
Ionospheric Effects and Gradients Monitoring
The broadcast signals travelling from the GNSS satellites to the receivers on earth have to traverse the ionized upper atmosphere known as the ionosphere. This causes propagation delays which translate into errors in the calculated vertical and horizontal positions. A thorough analysis of ionospheric delays and related gradients is essential to the success of the introduction of GBAS into operation.
This is done by establishing a local or regional threat model of the ionosphere. The implementation DLR GfR recommends to fulfil this need is a local ionospheric gradient measuring station at the location of the airport, consisting of several fixed GNSS reference receivers together with the needed network and data processing infrastructure. DLR GfR operates systems of this kind remotely from its premises at Oberpfaffenhofen, Germany. Our highly experienced engineers collect the data needed to establish a local threat database and complement additional, large scale ionospheric behaviour information in order to define the expectable ionospheric threat conditions at the airport.