There is an undeniable relationship between EW and Signals Intelligence (SIGINT), which can lead to confusion and misinterpretation. The relationship between EW and SIGINT in the most part is relevant only to ESM. SIGINT comprises of 2 main elements: Communications Intelligence (COMINT) and Electronic Intelligence (ELINT). In simple terms and to a large extent, COMINT and ELINT mirror the EW functional areas of CESM and RESM. Generally, EW is conducted by the military, using military equipment and for military purposes on military operations, whereas SIGINT is generally undertaken by intelligence organisations. Intelligence organisations are usually a combination of military and civilian personnel and their SIGINT missions can be undertaken outside the scope of military operations. SIGINT is normally more strategic in nature, and source protection is a major factor in classification levels. EW is tactical, however there is normally a vital need for SIGINT support to military operations and therefore the relationship between both needs to be understood and taken into consideration during all planning phases on operations.
COMINT and ELINT data provide much of the information needed for successful prosecution of EW, for example emitter databases. Furthermore, the use of commercial communications technology developed for military use means that SIGINT and EW are frequently engaged in technically similar target arrays. Most nations now have close links and robust communications between the 2 disciplines.
The following are the key characteristics of ESM: • It is used only during crisis and war. During peacetime, EW and ESM will interact with SIGINT and benefit from its product, in particular building of databases.
• It is one of the few tactical information gathering systems which has the potential to provide cover to the limit of the Force Commander’s area of interest • It provides all weather, day/night, long-range information gathering systems at the operational and tactical level monitoring activity in the EM environment • It exploits an adversary’s EM emissions and can provide information on the adversary’s capabilities and intentions • It is offensive and passive, but be aware that its C2 systems can produce a unique signature that can be exploited by adversary EW • It is a non-intrusive method of signals collection
1.8.7. ESM Activities
During the initial stages of a crisis or during preparations for war, EW efforts are stepped-up in an effort to improve knowledge and readiness. In this respect ESM activities will increase in tempo and focus. The immediate threat will become the priority. The following activities, therefore, usually take place: • Individual nations, if on a Combined operation, may put increased emphasis on updating the technical parameters of all communications and non-communications systems in their area of interest. • Creation of own and friendly EOBs to ensure interoperability of systems and reduce potential for fratricide. The Electronic Warfare Co-ordination Cell (EWCC) must be kept informed of friendly EOBs, specific equipment parameters and changes made. Own and friendly EOB information will be correlated with known adversary EOBs to create a consolidated Area of Operations (AO) EOB. • Development and production of Standard Operating Procedures (SOP), Rules of Engagement (ROE), and any specific “Actions On” for the operation. For Combined operations, higher level Memorandums of Understanding and Agreement will provide the mechanism to exchange nationally held data.
There are 3 main functions associated with ESM and they are shown along with the 4 sub-divisions of the ESM process: search, intercept, direction finding (DF) and analysis. The end product of this process will provide vital information and intelligence on the adversary, such as the establishment of an adversary’s EOB, strengths, weaknesses, dispositions, reactions and intentions.
Search
Search involves the reconnaissance of the EM spectrum for adversary emissions. An experienced EW operator will scan through the EM spectrum having already been informed on targets (transmissions) of interest to the J2 Intelligence Staff. Upon detection of a target of interest, the frequency will be passed to an EW intercept operator for further exploitation. Although this process can be quite slow, modern automated wide-band search receivers have now made it possible to scan portions of the Radio Frequency (RF) spectrum to identify active targets of interest.
Intercept
The intercept process further classifies the emission by both its external characteristics (RF, modulation etc) and the internal information if available. If the emission is encrypted, very little internal information is likely to be available. The EW intercept operator will log as much information as possible extracting all potential intelligence. A transmission using clear voice will have a log of its activity made by the EW intercept operator detailing what was said, however when done live, it is very unlikely that full (verbatim) copy will be possible. Realistically, the EW intercept operator ill log or “gist” only the most relevant information (locations, intentions, reactions etc) but good practice is to make a recording that allows further extraction of information following a full transcript of the activity in slower time.
Direction Finding (DF)
An emitter’s location can be obtained using the DF technique. This involves measuring the bearing at which the target signal arrives at a specialist EW DF receiver. If only one DF station is used then a line of bearing (LOB) is produced. This will provide only the direction to the transmitter but will not actually locate the target unless the distance from the DF sensor is known, which is unlikely. Two DF sensors will provide a better indication of where the target transmitter is located; however it is best practice to deploy 3 or more sensors to provide a fairly accurate location of the target. This is called Position Fixing (PF). When 3 or more sensors each provide their LOB, an ellipse can be drawn on a map, in which there is an approximate 90% chance the target is located.
Optimum accuracy of a DF system is approximately 1 degree, however at longer distances accuracy can vary up to 3 degrees and even more at the very limit of the target being audible. At distances of 30-50 km the target location ellipse will be quite large and this precludes DF being used for Target Acquisition. However, even at 3 degrees variation, DF is useful to cue other ISTAR resources to determine a more accurate target location. Figs 7 and 8 below show a typical land-based EW deployment of 4 DF sensors attempting to PF an enemy transmission and an aircraft attempting the same PF using a “rolling” baseline
Direction Finding & Position Fixing
Aircraft Direction Finding & Position
Analysis of EM emissions is carried out for multiple objectives, which include:
·. Adversary’s intentions
·. Adversary’s response to own or friendly Information Operations (INFO OPS)
·. Affects of own or friendly ECM operations
·. Establishment of a comprehensive EOB
·. Targeting for kinetic action
The analysis of traffic collected by ESM sensors should, if at all possible, be fused with other intelligence Sources and Agencies (SANDA). There is a “special” relationship between EW and SIGINT and product from both can be similar and complimentary, but fusing Imagery Intelligence (IMINT) and / or Human Intelligence (HUMINT) for example, will give much greater granularity and credibility to the information derived from the ESM intercept and DF. The fusion of all the information by the J2 All Sources Cell (ASC) can provide crucial intelligence to the J3 Staff in order to allow the Commander to make key decisions.
