11.
Guidance.
As a guide to the survey party, the tactical, operational, and weather
conditions existing at the time of survey and the dose should be weighed
against the following factors:
a. The slower the aircraft speed and the shorter the time interval
between readings, the more accurate the results.
b. The unreliability of survey data obtained at heights of more than
150 meters above the ground. A height of 60 meters is considered optimum.
c. High winds have no effect on the response time of the AN/VDR-2.
d. The combination of ground speed and reading time interval should be
selected so that the ground distance between readings is not more than 500
meters.
For increased plotting accuracy, at least 10 readings between
checkpoints are desirable.
e. Air-ground correlation factor data should be taken where aerial and
ground dose rates can be read most accurately on the survey meter, for
example, in the dose rate range of 5 to 10 cGyph.
12.
Factors Influencing Reliability.
With the guidance and procedures outlined, aerial surveys provide the
control party with adequate and sufficiently reliable data. Generally, the
dose rate determined by aerial survey varies from the true dose rate at the
ground location.
Reasons for variance are survey meter, pilot, and
monitoring errors and errors due to contamination of aircraft at touchdown
for ground reading, and the overall system errors.
CM5206
4-16
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