Detection Systems Section

Alan Sewards, 1977

CRC Photo 77-34930

The Detection Systems Section was formed at the time of the creation of DRTE, in part to assume responsibilities in Electronic Warfare (EW) which had been carried out by NRC throughout World War II and of which NRC wished to divest itself. These responsibilities included the development of technology to counter jamming of the various North American radar defence chains, such as the DEW line, Mid Canada Line, and Pinetree Line. In order to be able to do this, it was necessary to have the means to generate jamming and to measure its effects, and the Section, with industrial support through DND Project "Napkin", developed one-off jammers and vehicles containing receivers and analysis equipment which was used to conduct trials against selected radars. One of the means used to reduce the effect of jamming was the "Dicke-Fix" receiver: versions of this were developed for the Canadian radar chains and tested against various forms of jamming.

A related program was the "Back-up Interceptor Program" or BUIC. This was an investigation into whether it was possible to locate jamming aircraft based on their emissions using a cross-correlation technique.

Another offshoot of this work was the development of a battlefield receiver which could detect that the operator was being illuminated by a radar and signal an alarm. This receiver, named the Micradet (microwave detector), was the forerunner of the current crop of radar warning receivers now routinely fitted to almost all military aircraft. The receiver was developed by CGE in Toronto with DRTE acting as the scientific authority on behalf of the army who was the sponsor. Unfortunately, although the receiver prototypes worked very well and met all objectives, there was insufficient support in the operational ranks of the army for its production and deployment.

At the same time as support was being given to the Air Force and the Army on the activities described above, interest was also being shown by the Navy on deployment of Electronic Support Measures (ESM) receivers if they make accurate measurements of the signal as distinct from just producing a warning. The navy had deployed several types of receivers including the WLR-1 (a tunable microwave receiver originally developed for electronic intelligence purposes) and the UPD-501, which could do direction-finding on radar signals. Project Zander was created by the Navy to allow for R&D to be carried out in support of these receivers and to investigate new techniques, and to provide industrial support where needed. One of the concerns was identification of the type of radar from the measurements made on the received signals, such as frequency, pulse width, pulse repetition frequency and direction. This had to be done by looking data up in a large book, which was not very effective and was time-consuming. Some of the staff in the Section had the idea of using the newly introduced mini-computers to carry out this function, and after further study realized that the mini computer could do far more, to the point of being able to automate most of the receiver functions.

This realization occurred at the same time as the UK was developing a new type of receiver called instantaneous frequency measurement (IFM), which could make measurements of the various parameters of interest within the duration of the radar pulse and produce the output instantaneously in digital form. Under Zander, a program was started within the Section to build a prototype processor for the UK receivers. This processor had two parts: a digital preprocessor which processed the incoming stream of data from the IFM receiver, reducing it in an intelligent manner to a rate where the mini computer could handle it, and the software running on the mini computer which sorted out the incoming data stream into pulse trains from the various radars in the environment and measured secondary parameters such as pulse repetition interval and scan period, as well as doing the look-up identification task which had been the original stimulus for the work. This work was very successful and was tested at sea using the UK receivers on a Royal Navy ship operated by the Admiralty Surface Weapons Establishment at Portsdown. As a result, the Canadian navy decided to adopt the concept and proceed to develop it further, using Canadian Westinghouse as the contractor. Ultimately, the system, now named CANEWS, was manufactured by MEL Defence Systems (a company set up specially to build CANEWS) located in Stittsville, and is now on all Canadian warships.

Prepared By

Alan Sewards, Friends of CRC