DLR channel measurement programme for low Earth orbit satellite systems

The German Aerospace Research Establishment (DLR) is currently performing some measurement campaigns for channel effects related to low Earth orbit (LEO) satellite systems. The programmes comprise narrowband propagation measurements, wideband propagation measurements in a bandwidth of 10 to 30 MHz, as well as interference measurements for the satellite up- and down-link. For the narrowband and the wideband experiments, an aeroplane is modelling the satellites. Radiating a test signal at 1.8 GHz, the aircraft is flying on specific paths: (a) circles with various flight heights and radii; thus, the receiving area on the ground is fully characterized as a function of the azimuth and elevation angle; and (b) paths simulating the satellite´s motion in azimuth and elevation. For the interference measurements, a spectrum analyzer samples the noise spectra. Measurements have been performed at several L- and S-band frequencies. Hits from fixed service transmitters into the satellite antenna are the main effects on the up-link, whereas man-made noise (e.g., caused by microwave ovens) dominates on the down-link. Selected results of all campaigns are presented