A multipath channel model for wideband aeronautical telemetry

The paper presents a multipath channel model for wideband aeronautical telemetry links at DoD test ranges. Channel sounding data were collected at Edwards AFB, California, at both L-band and lower S-band. Frequency domain analysis techniques were used to evaluate candidate channel models. The channel model is composed of three propagation paths: a line-of-sight path and two specular reflections. The first specular reflection is characterized by a relative amplitude of 70% to 96% of the line-of-sight amplitude and and a delay of 10-80 ns. This path is the result of "ground bounces" off the dry lake bed at Edwards and is a typical terrain feature at DoD test ranges located in the western USA. The amplitude and delay of this path are defined completely by the flight path geometry. The second path is a much lower amplitude path with a longer delay. The gain of this path is well modeled as a zero-mean complex Gaussian random variable. The relative amplitude is on the order of 2% to 8% of the line-of-sight amplitude. The mean excess delay is 155 ns with an RMS delay spread of 74 ns.