Radar System Engineering

sm. 51] TYPES OF RA DAR-BEACON SYSTEMS 247
system, ” involved simultaneous determination by two ground
stations of the ranges of a beacon-carrying aircraft with great
accuracy. Coded signals for guiding the navigation of the plane
were given by the radar sets by suitable modulation of the interrogating
pulses.
3. Portable beacons. Portable beacons used with portable interrogators
form the basis of anew and accurate system of surveying.
1 Gontrolbw Controlbox
I
FIG. S.3.—Component parts of the AN/APN-19 beacon. The AN/A PN-19 is a IO-cm
beacon designedfor installationin aircraft.
The position of ground
fixed by measurement
known points.
radar sets can sometimes conveniently be
of ranges to portable beacons placed at
Ship
Radar.
1. Fixed ground beacons. The beacon is here the radar analogue
of the old-fashioned lighthouse. Since range to the beacon is
measured aswellas its bearing, observation of asingle beacon gives
two intersecting lines of position and a fix more accurate than is
customarily obtained by other methods.
2. Shipborne beacons. This combination can be of use principally
for identification.
3. Airborne beacons. Beacons have facilitated control of military
aircraft from a ship, and have been useful for identification of aircraft.
Inthepast war, they were used toenable ships to horn eon
aircraft that were orbiting in regions where submarines had been
sighted.