GNSS receivers for space applications

The new receivers are focused on the use of additional L2C and L5 frequencies for navigation, greatly expanding potential GPS use, and on a high degree of miniaturization. The use of additional frequencies allows accurate correction of ionospheric propagation delay, thus improving the positioning accuracy, and also the introduction of pseudolite-tracking capability (1340 MHz) for GEO satellites. Advantage of navigation with pseudolites is the continuous visibility, which is especially critical during orbital manoeuvres.

Though parallel and with the same ultimate objectives, the approaches of the two companies are quite different. Alcatel is using their L1 Topstar 3000 receiver and adapting its baseband processing and radio frequency front-end. The L5 study phase incorporates both existing and new technology.

The Austrian system incorporates entirely new components and can be integrated in a flexible way. Not based on any current receiver, it will incorporate a three frequency front-end and utilize a baseband processor from another ESA related activity. Austrian Aerospace is also developing modular software, hoping to make their system more easily adaptable to different missions.