All you need to know about direction finding and radiolocation techniques
What is direction finding and radiolocation?
Detecting emissions is always the first step. But often not only the existence of a signal of interest but also the location of the emitter.
The task of a radio direction finder is to estimate the direction to an emitter by measuring and evaluating electromagnetic field parameters. Usually, the azimuth angle to the emitter of interest is sufficient; the measurement of elevation is of interest for emitters installed on airborne platforms and especially for the direction finding of shortwave signals. Direction finding is therefore an indispensable first step in radiomonitoring, particularly since the content of such emissions is usually inaccessible.
Radiolocation of emitters is often a multistage process. Countrywide direction finders allow an emitter to be located to within a few hundred meters by means of triangulation. The emitter location can be determined more precisely with the aid of direction finders installed in vehicles. Moreover, portable direction finders allow searching within the last 100 m, for instance in buildings.