Accession Number : AD0707710

Title :   PRECIPITATION EFFECTS ON OMEGA AIRCRAFT RECEIVERS.

Descriptive Note : Final rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Eisenberg, R. L.

Report Date : 18 MAY 1970

Pagination or Media Count : 29

Abstract : Omega is a very-low-frequency (vlf) radio navigation system characterized by very long range and an accuracy on the order of 1 to 2 mi with respect to earth coordinates. Early flight tests of Omega aircraft receivers using vertical electric-field antennas achieved excellent results in good weather but experienced almost constant signal loss in precipitation conditions. Signal losses appeared to be caused by precipitation static and shorting of the insulation at the bases of the antennas. Modifications of vertical antennas, including shielding of the leading edge and improved base insulators, reduced but did not solve the problem. An experimental NRL-designed-and-constructed crossed-loop antenna system improved reception characteristics with respect to both wetting and static pickup. NRL has evaluated the performance of modified vertical antennas and crossed-loop antennas in the laboratory and on Omega test flights. These flight tests have revealed that the crossed-loop antenna offers adequate sensitivity and a significant reduction of precipitation effects and thus provides all-weather operation of Omega aircraft receivers. (Author)

Descriptors :   *RADIO NAVIGATION, *RADIO RECEIVERS, *OMEGA NAVIGATION, VERY LOW FREQUENCY, PRECIPITATION STATIC, AIRBORNE, AIRCRAFT ANTENNAS, LOOP ANTENNAS.

Subject Categories : Air Navigation and Guidance

Distribution Statement : APPROVED FOR PUBLIC RELEASE