Frequency band protection method - using fixed receivers to measure attenuation of protected frequency band signal and determine position of interference source e.g. mobile radio unit, with unit operation inhibited if required

摘要

The method involves measurement of characteristic signal attenuation parameters at two or more points in the frequency band over a period of time. Automatic radio referencing determines the position of a mobile unit (1). The parameters and the relative position of the mobile unit are processed to determine whether or not to inhibit certain mobile units. A radio signal can be transmitted via satellites to automatically start the inhibition operation. The measurements are made by a receiver assembly (4) with an omnidirectional antenna, using parts common with the protected system. Radio sources (3) in the measurement band emit a narrow band constant amplitude signal from an omnidirectional antenna or several sources are used to emit frequency or time division multiplexed signals.