New Evidence of Radio Stations Interfering With Fleet GPS Locator Signals

Representatives from the Fleet GPS Locator industry this year presented evidence to members of the Communications Commission’s laboratory that proposed broadcast stations interfere with car locator signals. This meeting and subsequent documents did not prevent the Bureau of International Signals from regulating ancillary ground component operations across the United States, installing up to 40,000 high-power transmitters near GPS locator frequencies.

Documents describing the tests stated that the broadcasting stations had a severe impact on the GPS frequency bands and would cause such catastrophic interference problems to the operation of GPS receivers that they would cease to operate in the vicinity of these transmitters. . The International Signals Bureau waived its own rules to allow potential jammers to broadcast from powerful land-based transmitters in L-Band 1 (1525 MHz-1559 MHz). This frequency band is located near the frequency band (1559-1610MHz) in which GPS locators and other global positioning systems (GNSS) operate.

Prior to the decision, the U.S. Fleet GPS Locator Industry Council and GPS Locator Manufacturers asked five members of the Office of Engineering and Technology, including its director, two members of the International Signals Bureau, a member of the Department of Public Safety and Homeland Security and Two members of the Wireless Telecommunications Bureau submitted experimental evidence on wide-area GPS locator interference caused by proposals to convert a portion of L-Band 1 to high-power terrestrial broadband.

This document conveys test results on a common portable consumer automotive locator and a common general aviation receiver. Consumer GPS locator devices began to experience interference at a power level of 5.8 kilometers from the analog transmitter. The consumer device lost its fixed position 1.1 kilometers from the transmitter.

During laboratory testing, the Fleet GPS Locator signal was simulated using a GPS locator simulator, representing a constellation of 31 GPS locator satellites, which is the current configuration. Signal simulation uses a signal generator for digital modulation, which is amplified to achieve the corresponding signal strength. Complete technical indicators and parameters can be found in subsequent press documents.