Doppler Navigation Radar
This project was begun in 1952 by B.A.Walker who joined DRTE/EL from UK Defence Research. The RCAF was interested in having continuous ground speed data and drift angle for pursuit aircraft in conditions of cloud or over vast areas of northern Canada and the seas where landmarks were very few and far between. The UK had already developed such a system for large bombers but this weighed several hundred pounds and required considerable electrical power. It did, however, function at all angles of vertical elevation of the bomber. The RCAF wanted a similar system if this could be of much lighter weight, certainly no heavier than a man and preferably lighter still, with a power requirement of less than one watt* which could be provided from existing aircraft power sources. As Walker soon became superintendent of the Electronics laboratory with wider responsibilities, R. Keith Brown became project leader with John Barry responsible for much of the laboratory development.
The concept was to use much lighter solid state components, which were then rapidly becoming available, and to design a system that functioned within ten degrees of horizontal. For climb angles of the aircraft outside this range the speed and drift values continued constant from the last values obtained until the aircraft heading returned within the range. These intervals were nearly always very short and made negligible differences to the desired information. By doing this a considerable saving in weight was possible. Harold Raine acted as engineer in charge of flight trials and some ten engineers and technical officers supported the project, including Norman Harrison. Two others, Dick Stacey and Chester Mott, left later to form the nucleus of a new electronics firm at Carleton Place - Leigh Instruments - which achieved great success in subsequent years.
Parallel with this effort, Canadian Marconi Company, under an RCAF contract directed by DRTE, developed the microwave portion of the system as well as the integration of the whole system into a package for manufacturing* The frequency modulation technique devised by Keith Glegg of Marconi was a key factor in the success of the system, which became a world leader in light-weight Doppler Navigation.
Several of these models were installed in RCAF aircraft and functioned as stipulated with a weight just under 100 pounds. B.A. Walker was instrumental in persuading Marconi Co. to exploit the system for commercial aircraft and their commercial models were eventually sold to several major airlines and to US Defense Departments. These sales amounted to some $175 million in subsequent years.
Meanwhile the DRTE team further extended the use of solid state components and produced a Doppler Navigation System at fifty pounds in weight. This did not, however, receive additional financing so became a museum piece in DRTE.
Frank T. Davies/ht
9 October 1973.
*possibly one kilowatt
See also the article "Doppler Navigator Development" written by John Barry
