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Recent Developments and Future Trends
In December 2000, SaabTech Electronics received an order from Germany for the adaptation of its BOW-21 Radar Warning Receiver (RWR) for the German TORNADO fleet. The BOW-21 was first ordered in late 1999 for Sweden's JAS-39 GRIPEN. The German production contract is expected in 2003, with first deliveries tentatively scheduled for 2004-5. The manufacturing process will involve close co-operation with the German industry.
The German Armed Forces' decision to adopt the Swedish BOW-21 system was received by many independent observers of the defence procurement scene as a rather extraordinary development, in that Sweden is not a member of the TORNADO programme while there certainly is no shortage, in Germany as well as in the other TORNADO member countries, of highly capable electronics industries. This situation has focused attention on the operational and technological aspects of the development of RWR systems is Sweden.
General Considerations
The designers of modern Radar Warning Receivers (RWRs) are faced with an environment that is continuously increasing in complexity. The number of radar sources is expanding and they are more varied as regards both the platform (to include fixed or mobile ground installations, ships, aircraft and ultimately the attacking missiles themselves) and the use of the whole range of advanced emission control technologies. The increasing range of both weapons and sensors mean that RWRs must detect priority threats at much greater distances if they are to alert the pilot and/or initiate countermeasures early enough to be effective. Moreover, the speed of the aircraft itself means that new areas and new threats are constantly coming into play, while others are rapidly left behind.
Dealing with a radar environment of such density and complexity requires a marriage of hardware and software. Sensitivity in detecting radar signals, selectivity in distinguishing pulses and accuracy in recording the characteristics of each pulse for processing are the primary duties of the hardware. The software must then discriminate between different emitters (correlating all associated pulses); identify their type - if possible - by reference to library information; locate each emitter as accurately as possible; and assess the threat level it represents. It must then present to the pilot a constantly updated situation picture, warning him...