In-loop geometry means fewer corrections need to be applied to correct for lag offsets, thus preserving the integrity of the originally measured data, together with higher accuracy as to where the anomaly originated. Additionally, the rigid slung load platform’s position and orientation is continuously monitored and together with its separation from the aircraft means that Caesium-vapour magnetic data is not being corrected with lower frequency response fluxgate data in the compensation calculations. Corrections regarding frame geometry are actual and not approximated.
Confidence in the DATA
Unlike many other systems, SkyTEM’s low drift means that frequent flights to high altitude to determine drift corrections are not required (some systems require this test several times per flight). On longer surveys, repeat flights to high altitude are conducted approximately weekly in order to verify that the null-coupling, bias and standard deviations have not changed. High altitude checks are also performed following any potential damage to the frame (e.g., hard landing) or replacement of major electronic components.
- Primary Field Compensation (PFC) allows earlier time channel data to be used in the aLCI inversion, thus resolving shallow layers even more effectively than before.
A spectral analysis will be performed daily on raw, unstacked data to monitor for VLF and sferic activity. In any case our primary sensor (due to the in-loop design of the system) is the Z and is significantly less affected than other systems.
Data will be re-flown at the Contractor’s expense when the standard deviation of the normally processed late (e.g. 8904 μs for the 304) time gate EM channel continuously exceeds 2 nV/m2 for Z-component data and 6nV/m for X-component data over a horizontal distance of 2 km under normal (conditions free of man-made interference e.g powerline interference, radio transmitter, etc) survey conditions.