RADAR IN ATC
In 1935 Dr. Robert Watson-Watt of the United Kingdom determined that "radio detection" was feasible. By 1937, the first operational station of the British Home Chain was built. It was this technological advance that was the forerunner of the use of Radar in ATC today. Radar was used extensively by the Allies during the war. In late 1941, feasibility of experiments in blind landing were carried out at Quonset Point Naval Air Station. On 22 December, 1942 Ensign Griffin USN made the first Ground Controlled Approach at Quonset Point, talked down by Lt Aurand, USN.
The U.S. Army contracted with Gilfillan and the U.S. Navy with Bendix to produce the first ATC radar sets (AN/MPN 1). Training of personnel on the first GCA sets was somewhat different than today. The tasks of the crews were as follows:
First Director - Performed initial aircraft pickup and vectored to base leg.
Second Director - Vectored aircraft from base leg to final and coordinated with tower; also performed the same duty as First Director when more than one aircraft was being controlled by the unit.
Azimuth Tracker - Tracked aircraft on final approach by using cursor.
Elevation Tracker - Tracked aircraft on glide slope by using cursor.
Final Controller - Conducted final approach by giving readings from an Error Meter.
The Azimuth and Elevation trackers did not have direct radio communication with pilots but gave their readings to the Final Controller. In some cases pilots expressed a great deal of enthusiasm for the GCA facilities, but every now and agin, there was a Commander who expressed disbelief that some "groundling" would have the temerity to attempt to tell him how to land his aircraft. In the Story of GCA, written by Chester F. Porterfield, there is a story of a Colonel Base Commander who did not believe the GCA crew could ever help him.
"The crew got all set up on their own and simply waited for a day when the Colonel got himself caught up in a heavy fog, and had no choice but to use the GCA facilities. He was brought in to a perfect landing, though the field was so thoroughly closed that a jeep had to be sent out to guide the plane to its dispersal point; the jeep drove off the perimeter road twice in the fog. Needless to say, the Colonel changed his mind and became a staunch GCA supporter from that day onwards."
GCA was used at the main RAF Bomber Base of Elsham Wolds, critical bases of Coastal Command and Prestwick. GCA was used extensively by the Allies at war's end, but it was the Berlin Airlift of 1947 when GCA became the mainstay; there was little doubt that it was here to stay.
RADAR IN RCAF MILITARY ATC
The RCAF made its first purchases of Ground Control Approach (GCA) units in 1948 and 1950; the Gilfillan AN/MPN 1(c) units were installed in Montreal (St. Hubert), Greenwood, Edmonton and Sea Island.
In 1951, the RCAF purchased a surplus USAF AN/MPN 1(c) which was installed at Fort Nelson B.C. The AN/MPN 1(c) consisted of a prime mover (Diamond T Truck), an operations trailer, and a power unit. The equipment was mobile so it could be moved about the aerodrome, and sited on surveyed, prepared pads which served the runway in use.
The Operations trailer housed two control positions, consisting of a Surveillance scope, maximum range - 40 miles and two Precision Radar (PAR) scopes. The PAR scopes were interesting in that one had a range of ten miles, while the other's range was three miles and the controller moved back and forth between them, depending on which range was needed for controlling. The antennae servos for the PAR were operated by foot pedals and the cursors were manually set overlays. The Operations trailer had a window at the back just to the left of the PAR scope, covered with an appropriate curtain. This window was a boon to the more capable (and sly) PAR controllers. On a certain day I remember a particular Sgt (later Captain) Glen Hazlett carrying out a PAR approach, and just as the plane was due to touchdown, leaning over, opening the curtain a crack and intoning, "You are just about to touchdown with your wheels...NOW!" Such a degree of control and professionalism never failed to impress the pilots.
The success of the purchase of these first GCA units prompted the RCAF to purchase more Gilfillan units, AN/CPN 4s this time, which were installed at RCAF Stations:
Comox;
Gimli;
Portage La Prairie;
North Bay;
Ottawa;
Trenton;
Bagotville;
St. Hubert;
Greenwood;
Chatham, NB; and
Winnipeg.
1 (F) Wing Marville, France;
2 (F) Wing Grostenquin, France;
3 (F) Wing Zweibruecken, Germany;
4 (F) Wing Baden-Soellingen, Germany; and
30 Air Material Base, Langar, England;
Cold Lake, Alberta received the last unit of this purchase in 1954.
The AN/CPN 4 consisted of two trailers, a power trailer, and operations trailer. The power trailer contained two diesels, an air conditioner, and a gas-operated heating unit. The operations trailer held all the radar equipment and three operating positions. Each position had a 40-mile surveillance scope and a 10 mile Precision Scope. All alignment equipment was electronically operated.
Prior to completion of the contract, the requirements changed to purchase AN/MPN 11s. The equipment of the AN/MPN 11 was identical to the AN/CPN 4 but the trailer construction was vastly improved. While the CPNs were bolted together, which allowed drafts and rain to enter, the AN/MPN 11 trailers were rivetted and welded eliminating leakage. The ATC view held that the only difference between the units was "that the MPN11 did not leak". Although originally planned to be mobile, the AN/CPN 4 and the AN/MPN 11 became fixed-site units providing PAR to only one runway. Later, turntables at the RCAF NATO Stations allowed the PAR to provide approaches to opposite ends of the main Fighter Runway.
In the mid 1950s, the RCAF purchased several sets of the AN/FPN-33 Quad-radar. These units were installed at:
Namao;
Churchill;
Winnipeg;
Rivers;
Torbay;
Summerside
Val d'Or;
Toronto/Downsview;
Vancouver;
Saskatoon; and
RCN HMCS Shearwater.
1 (F) Wing Marville, France;
2 (F) Wing Grostenquin, France;
3 (F) Wing Zwiebruecken, Germany;
4 (F) Wing Baden-Soellingen, Germany; and
30 Air Material Base Langar, UK.
Once again, this contract was changed partway through to provide the RCAF with the AN/FPN 36, a much more stable Quad-radar.
Quad-radar derives its name from the four functions for which it was originally designed.
Height-finding;
Surveillance;
Precision Approach; and
Airport Surveillance Detection.
The RCAF never used the four functions, but rather only the Surveillance and Precision Approach portions. The unit consists of a mount position which held the pedestal, transmitter, receiver, antenna group and an indicator position. The indicator was a single display which could only be used in one function at a time; i.e. either Surveillance or Precision mode.
During the 1960s, each Fighter Wing in Europe had an operations convoy which included a quadradar. These units would deploy regularly to their applicable satellite field (Bertix and St. Hubert in Belgium and Rocroi in France) with a squadron of Sabre aircraft; these operations were usually one to two weeks in time. As a result of these exercises and with a perceived need to provide mobile support for tactical and transport operations, a mobile support team was permanently established at CFB Trenton and called the ATCCU (Air Transportable Communications and Control Unit). This unit consists of Communications Specialists and ATC personnel with portable Quadradars, a Tower and Radio/Tacan vans. The Quadradar was lightweight, compact and ruggedly built so it was a natural choice for this type of operation.
Updated: November 28, 2004