Analysis of VHF and X-Band Telemetry Systems Degradation by Reentry Environment.
Research rept. May 69-Jun 70,
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
Pagination or Media Count:
The degradation of VHF and X-band telemetry by the reentry plasma sheath has been analyzed for recent flight tests of a hypersonic reentry vehicle. A self-consistent technique utilizing the received signal strengths of both the VHF and X-band transmitters was used. It was determined that the attenuation was caused by electrons flowing back over the antennas from the stagnation region at the nose. For the X-band signal, the attenuation was a result of pattern distortion caused by refraction in the plasma layer and distortion of the field distribution in the antenna aperture. At VHF, the plasma layer is electrically thin, and the signal loss resulted from the combined effects of reflection and absorption. Author