Signals Intelligence (SIGINT) in Avionics Systems

Signals intelligence consists of a number of different but related activities that are usually complementary in their employment and results. SIGINT is acknowledged as being used by most military forces and governments. Security surrounds its exact operational deployment and the degree of capability available to governments.

SIGINT in Electronic Walfare Elements

SIGINT consists of three major activities:

1. Communications intelligence (COMINT) which is achieved by the interception of communication signals of all types – telegraphy, voice or data – and obtaining intelligence on a prospective enemy’s intentions, capabilities and military preparedness. Frequently, the text of messages is enciphered and cannot be read immediately. However, there is still a great deal of intelligence to be derived from signals traffic analysis and direction finding which can provide both tactical and strategic advantages. Patterns of communication can be used to identify the state of readiness and location of participants. Sudden communication activity may indicate battle readiness or changes of plan. Silence can indicate departure of forces from an area, or deliberate radio silence prior to an attack. A database of such communications activity is useful in establishing a potential enemy’s radio discipline and movements. Selective or broad band jamming can be deployed to restrict useful communications.

2. Radar intelligence (RADINT) which uses standard or special-purpose radar systems to obtain intelligence on an enemy’s capabilities, deployments and intentions. These radar systems may be space, air, sea or land based. RADINT is collected by an electronic support measures (ESM) system employing a number of sensitive antennas that are able to detect radar signals in different bands. As well as detecting the signal, the ESM also establishes a precise direction of arrival of the signal. Analysis of the signal characteristics such as frequency, pulse duration, amplitude and the spacing of main power lobes and side lobes will identify a particular type of radar. Continued collection of analysed data mapped onto the types of platform carrying different radar systems enables an experienced EWoperator to identify a particular ship, aircraft or land-based system type. There are claims that experienced operators can even identify an individual platform by its radar transmitter characteristics. A successfully managed EW campaign can identify radar types and their exact locations for subsequent database update or for selective jamming. This technique is known as ‘fingerprinting’ and it requires some very clever waveform analysis equipment.

3. ELINT Electronic Intelligence involves the interception and analysis of noncommunication radio-frequency signals, usually radar, to obtain many aspects of a nation’s intentions and capabilities such as technological progress, military preparedness, orders of battle, military competence, intentions etc.