Airborne Gravimetry from Strapdown Inertial Navigation System
21/09/2016 | 08:30 | Session 4: On the ground and airborne gravimetry
Author(s): Tim Enzlberger Jensen, Arne Vestergaard Olsesen and Rene Forsberg
Tim Enzlberger Jensen, Arne Vestergaard Olsesen and Rene Forsberg
For geodetic surveying, with the purpose of measuring Earth’s gravitational attraction for global models and geoid determination, DTU Space has been flying with spring-type gravimeters on a stabilized platform for 20 years. Recently, in collaboration with TU Darmstadt, we have been flying a Strapdown Inertial Navigation System (SINS) alongside the spring-type gravimeter. In this context, the SINS system has proven itself superior in precision, reliability and ease-of-operation. However, comparison with the older spring-type gravimeter has indicated that the long-wavelength part of the signal is still not fully controlled.
With all these promising indications, DTU Space has now purchased a new iMAR-RQH Inertial Navigation System (INS), intended for high-accuracy airborne applications. This system has been tested on a four hour flight across Denmark and is used for new surveys in the South China Sea, all in a strapdown configuration. Since the Denmark region is well-covered by both terrestrial and marine gravity observations, the airborne observations can be directly compared with a “true signal” in this area.
In the presentation we use the Waypoint software (Inertial Explorer) for processing the inertial data, and compare results to upward continued gravity data in Denmark. We also compare selected gravity data for new Malaysia offshore surveys, acquired by both the iMAR SINS and a Lacoste and Romberg (spring-type) system, in order to evaluate long-period drift and sensitivity to turbulence and maneuvers.