Barnard Microsystems Limited

Developing Unmanned Aircraft Systems to benefit Mankind

Radio Direction Finding - RDF

Above: experimenting with the possible location of a Radio Direction Finding antenna on an early InView.

A Radio Direction Finding (RDF) system, consists of several antennae connected to a signal processing unit and is used to find the bearing (angle) to a radio transmitter.

Radio Direction Finding is used:

  • to locate a radio transmitter, using “triangulation”: see www.rdfproducts.com;

  • to locate the source of interference signals, for example, from the ignition system of a petrol (gasoline) engine, or from the brushes in an electric motor;

  • as a navigation aid, using the known location of radio and/or cell phone antennas.

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Example of a Radio Direction Finding unit.

RDF

Example of a Radio Direction Finding device with multiple antennas.

From dma1418b1_pds_01a.jpg www.rdfproducts.com .

RDF

Bearing Errors – Standard Reflection Field

Antenna type

Operation details

Peak error

RMS error

Two-spaced

Adcock

Time Of Arrival

11.4°

8.0°

One-quarter size Doppler

4 arms

8.0°

5.4°

One-half size Doppler

8 arms

5.2°

2.8°

Full size Doppler

16 arms

3.4°

1.5°

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Example of an RDF antenna at the Thales outdoor stand at the Dubai Air Show 2007

RDF

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