VORTAC PERFORMANCE IN A SNOW AND ICE ENVIRONMENT.

• Main Author: Hollins,Clinton G.
• Other Authors: SCANWELL LABS INC SPRINGFIELD VA
• Format: Text
• Language: English
• Published: 1968
• Subjects: Active & Passive Radar Detection & Equipment; (*RADIO NAVIGATION; ARCTIC REGIONS); ICE; SNOW; DEICING SYSTEMS; ELECTROMAGNETIC WAVE REFLECTIONS; VERY HIGH FREQUENCY; OMNIDIRECTIONAL ANTENNAS; NAVIGATIONAL AIDS; RADAR STATIONS; PERFORMANCE(ENGINEERING); RADAR TRACKING; RADAR ANTENNAS; SCATTERING; TACAN; Arctic
• Online Access: http://www.dtic.mil/docs/citations/AD0665814; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0665814

Investigations into the performance of VORTAC installations operating in an adverse snow and ice environment are described. VOR system performance is analyzed using a computational program for determining the course errors produced by sections of a thin spherical shell centered on the antenna system. A near field formulation of the electromagnetic problem allows simultaneous computation of the course error curves for both ground checks and aircraft orbits. Specific examples of course error curves and graphical summaries of the variation in maximum course error as the parameters describing the scatterer are altered provide a foundation for discussion of the more significant distributions of snow. Natural accumulations are shown to be capable of producing out-of-tolerance conditions accompanied by inadequate monitoring. Possible solutions for the problem are briefly discussed. The results of thermal tests performed on a TACAN transmitting antenna in order to determine the deficiencies present in the existing deicing system are evaluated. Modifications of the TACAN and VOR monitor antennas which will eliminate unwarranted outages due to ice and snow accumulation on the antenna covers are described along with the results of tests on the modified equipment. (Author)