The study of moving base INS/GNSS gravimetry on a land vehicle

Abstract

Gravity is traditionally measured by land gravimeter; however it is time and labor consuming In order to overcome this deficiency and measure gravity conveniently vehicle airborne or ship gravimetry are developed but nowadays these equipments are still very expensive and lack operational efficiency Compared to traditional methods using gravimeters a moving base gravimetry system composed of a SINS/GNSS integrated system by mounting on land vehicle is relatively efficient labor and cost saving Compared to airborne gravimetry it also could provide highly accurate high spatial resolution and local gravity signals Besides The SINS/GNSS derived gravity can be used to study scientific topics; for example determining geoid investigating orogeny study sea floor structure hydrology mass inbalance The systems applied in this study include a navigation grade IMU with gyro and accelerometers biases less than 0 002deg/h and 10ug and GNSS receiver In our study there are two experiments for the plain area The first one was carried out along the highway from Tainan to Taian The second one started from Rende along the highway (National Freeway No 1→ Expressway 82→National Freeway No 3→ Expressway 86) and back to Rende in western Taiwan The routes were repeated more than once Therefore we could analyze the quality of our gravity estimates in terms of repeatability The capability of the IMU for gravimetry was tested in the static and kinematic mode respectively In the static mode the car was stopped five minutes every stopping point to perform ZUPT We can check if the GNSS acceleration and gravity disturbance are good or not The estimated gravity accuracy is at the level of 10mGal which indicates good applicability of the unit for geodetic purposes In kinematic mode the gravity disturbances have not reached a reasonable value until now Therefore we hoped it could be improved in the future work

Date of Award	2014 Aug 21
Original language	English
Supervisor	Kai-Wei Chiang (Supervisor)