Ground-based water level observations at Lake Walchen using reflected GPS L1 C/A and modernized GPS L2C signals

Abstract

Within the German Indonesian tsunami early warning system (GITEWS) project, the GeoForschungsZentrum Potsdam (GFZ) has set up a team consisting of the GFZ, the German Aerospace Center (DLR) and JAVAD GNSS to adapt and extend their new generation GNSS receivers for advanced scientific space applications on small low Earth orbit (LEO) satellites. The GNSS occultation, reflectometry and scatterometry (GORS) space receiver prototype consists of a commercial off-the-shelf JAVAD GNSS GeNeSiS-112 72 channel receiver board with raw data and position solution output. As major step forward compared to current space receivers, the new GORS receiver prototype supports tracking of the civil L2C signal of the GPS constellation. This will enable loss-less dual frequency tracking of occultation events down to very low altitudes. Signal simulator tests show that the prototype provides proper GPS measurements for orbit determination and scientific applications under the signal dynamics of a user satellite in LEO.