Airborne Gravity 2010 - Geoscience Australia

Airborne Gravity 2010
The prototype system hardware was ready for testing in early 2006, and an initial series of ground
based tests was used to prove the concept. For ground testing, the system was mounted in a van and
driven along a straight road to simulate as closely as possible an aircraft flight (Figure 3). Logistically
this type of testing is much easier to setup and far cheaper than aircraft testing (Figure 4). It also has
the advantage of making it much easier to follow the same ground track on every run. A long straight,
flat road is required which also has minimal obstructions for a clear GPS signal. In practice such roads
are not easy to find in Colorado and the test line road has several features which make it less than
ideal, such as elevation changes of a few tens of metres and bumps from road surface irregularities.
The disadvantages, while making the testing more challenging, also served to add some real world
turbulence and flight deviations which allowed for a more rigorous examination of how the system
might respond in an aircraft. The prototype system was tuned until it consistently exceeded the
1 milligal repeatability and 4 km filter resolution specification for a minimum of 4 repeat line passes
during a test (Figure 5). The system was then prepared for a series of airborne tests later in 2006
(Figure 4).
Figure 3. Prototype system set up in a van
for ground based testing in early 2006.
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Figure 4. Advanced prototype TAGS
mounted in a Piper Navajo for flight testing
in late 2006.