A balloon tracking system that uses the VHF omidirectional range (VOR) network

The VHF Omnidirectional Range (VOR) system is a primary navigational aid to aircraft in the United States. Although the quantity of stations in the United States exceeds that of other areas, VOR stations are found all over the world. An inexpensive balloon navigational package that uses the existing VOR system has been developed. It employs the principle of triangulation between stations to yield position information. The station selection can be changed by telemetry command during the balloon flight in order to maximize triangulation accuracy and to minimize effects of weak signals. The VOR radials are part of the telemetry transmitted from the balloon package. Preliminary results from several flights in Palestine, Texas indicate that this system may be a viable backup or substitute for the OMEGA system commonly used. Typical accuracy of the down point prediction has been ± 1 mile.