Omega Windfinding and GATE

Abstract

When fully implemented, Omega will be a system of eight very low frequency (VLF) transmitters providing global coverage for navigation. Recently, intensive design and development has exploited Omega for tracking sondes (both free-rising and free-falling) to determine wind velocity as a function of height. During the summer of 1974, several GATE measurement systems, including radiosondes launched from ships and dropsondes released from both aircraft and constant level balloons, will provide winds derived from Omega signals. While some GATE ship radiosonde systems will use other VLF transmitters for windfinding, the principles involved are essentially identical to those required for Omega windfinding. This paper formulates the analytical techniques needed to use Omega or other VLF transmitters for windfinding, discusses sources of measurement errors, reviews Omega wind measurement error experiments, and projects wind errors into the GATE ?B? area near 10N latitude and 25W longitude.