Navigational Aids
Gee AMES Type 7000
Gee
The Gee systems was the primary radio navigational aid used during the war in Europe and proved to be an invaluable homing system. It differed from the simple arrangement already described in minor ways, all of which were designed to make the task of the aerial navigator easier. To obviate the necessity of using different radio frequencies for each of the three transmitters and also to remove any confusion that might arise through not being sure whether the B pulse were lagging or leading the A pulse, it was arranged that the B transmitter pulses should be emitted with a 'standard' delay of 1 millisecond with respect to those from the A transmitter. Suppose, for example, that the transmitter A and B in Fig. 17.4 were at such a distance apart that wireless waves took 500 uSec to cover the distance AR.
Then along the perpendicular bisector of AB the two pulses would be received at times separated by the standard delay of 1000 uSec; at points nearer to B than to A the delay would be less than 1000 uSec and at points nearer to A, more than 1000 uSec and the hyperbolae could be labelled in the manner shown in the figure.
To enable the delay between the A and C pulses to be measured without confusion, the A pulse which is to be compared with the C pulse is made double. The complete cycle of transmissions from A, the "master" station and the two "slave" stations B and C consists of a pulse from A followed by a pulse from B 1000 uSec later, followed after a further 1000 uSec by a double pulse from A and
