Airborne Measurement of Earth Gravity by Comparing Three Kinds of Gravimeters

Abstract

NUDT (National University of Defense Technology) has developed a strapdown gravimeter based on the SINS/GPS named SGA-WZ01. From April to May 2012, an airborne gravimetry flight test was carried out in the South China Sea. In this flight test, except SGA-WZ01, a 3-axis inertial platform gravimeter, GT-1A, and a damped 2-axis platform gravimeter, TAGS, were installed to obtain the gravity information. This was the first time that such a flight campaign was undertaken in China. The flight test contains one repeated line flight and four gridded line flights. The evaluation of the repeatability is based on repeated surveying lines, and the evaluation of the internal accuracy is based on all gridded lines. The results show that both GT-1A and TAGS have systematic biases about several mGal for repeated lines along west-east and northwest-southeast repeated lines, and the repeatability of SGA-WZ01 is consistent along repeated lines in different directions. The accuracy of gridded lines without crossover adjustment of GT-1A is about 1.73 mGal, while the crossover accuracy is 2.76 mGal and 2.08 mGal for TAGS and SGA-WZ01, respectively. The outcomes show that the performance of the SGA-WZ01 is comparable to that of foreign gravimeters.