The following description
of Aerodist appears on page 2 of the August 1965 issue of "Australian
Aerial Survey Review".
an example of Adastra's co-operation with the National Defence Services.
This instrument is made in South Africa by the producers of the widely-used tellurometer
system, which is operated by microwave, and used for ground measurement of geodetic
As used in Adastra aircraft, Aerodist is designed for simultaneous measurement,
during flight, to three ground stations, known respectively as Red, White and
Its function is long-range extension of horizontal control, and aircraft positioning
in aerial survey.
The immediate effectiveness of Aerodist was seen in New Guinea when Adastra began
to fly an extensive project on behalf of the Australian Army Survey Corps.
First, Army land parties established ground stations, the most onerous part of
Survey Corps men were landed by helicopter in small clearings with equipment and
supplies in jungle country.
In one case, Army technicians found themselves working among the clouds, on the
brink of a 2,000 feet drop.
Speed of Aerodist survey resulted in as much progress being made in an hour as
would have been achieved in six months by land parties using conventional methods.
Aerodist gives accurate long-range extension of horizontal control in three ways.
 distance measurement between ground stations, using the aircraft as an intermediate
station (line-crossing technique)
 fixing an unknown ground station from two known ground stations using an aircraft
and continuous trilateration
 fixing two unknown ground stations by the foregoing means.
Aerodist accurately positions an aircraft in flight, continuously or at an instant
of camera exposure, and also determines altitudes.
In the Adastra aircraft, these facts were obtained by obtaining a fix in space
as function of three slant distances, using the Aerodist three channel system,
and by using two channels to measure slant distances while the third channel gave
direct height measurement from a ground station established at a known height,
the ground station antenna being set vertically."
channels of the Aerodist system required three separate antennae.
The original configuration had one antenna on top of the fuselage
and two on the belly. (photos A and B). This was subsequently
changed to one on the belly and one under each wing tip. (photos
C, D & F). As will be seen from these photographs, the ground
clearance for the (non-retractable) aft belly antenna was minimal.
By late April 1965, VH-AGS was being operated without any Aerodist
antennae, although the aircraft retained the mounting for the
upper fuselage location (photo G). It is believed that VH-AGS
was the only Adastra Hudson to carry the Aerodist installation.