Flight Tests of Digital Data Transmission at VHF.
Final rept. Aug 75-Jan 76,
INSTITUTE FOR TELECOMMUNICATION SCIENCES BOULDER COLO
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This report describes the results of a series of 11 experimental flights which measured the characteristics of air-to-ground digital transmission in the VHF aeronautical mobile frequency band. The tests were conducted for the Federal Aviation Administration at National Aviation Facilities Experimental Center in Atlantic City, NJ. Digital transmission rates of 2400 and 4800 bps were used with minimum-shift-keying MSK as the baseband modulation format. The MSK signal was transmitted on a test frequency of 120.85 MHz using conventional, airground voice communication equipment. A number of parameters were measured during the flights and an extensive decription is given of the bit error rates which were encountered. Received signal level was also monitored, and data describing average signal level and signal fading are presented. Other parameters measured were clock slips, carrier lossess, distribution of errors, and signal fading caused by aircraft maneuvering. The tests show that digital transmission rates of 2400 and 4800 bps can be supported, with existing FAA and ARINC equipment, at an average bit error rate near 0.00005. Author
- Radio Communications