Research On Methods Of Data Processing For New Airborne Gravimeters

The earth gravity field is of great significance in the field of geodetic survey, geological survey, geophysics, military applications and so on. Airborne gravimetry is a gravity measurement method which can quickly obtain the information of the area or local gravity field. It is not limited by ground transportation conditions, and with the advantages of high efficiency and wide range of measurement, so it has been widely studied and applied. In the western region of China, there is a large area with unknown gravity, which is urgently needed to carry out airborne gravimetry. The methods of data processing for airborne gravimeters are investigated in detail in this dissertation and the main research results are as follows:The study of window function FIR and Butterworth low pass filters applied in the data processing of airborne gravimetry is conducted. A Chebyshev optimal uniform approximation of FIR and a Elliptic low pass filter are designed for the data processing, and the influence of design parameters on their amplitude frequency characteristics is investigated and discussed. The selection and parameter design of low pass filters in airborne gravity data processing is summarized, which has certain reference value for the low pass filtering in airborne gravimetry data processing.For the domestic new strapdown airborne gravimeter, Kalman smoothing filtering method and cascaded method of window function FIR and Kalman smoothing filtering are both presented for the airborne gravity data processing, where the state equations and observation equations of Kalman filtering are established with the gravity anomaly as a expanded state variable. Dealing with the measurement data of the new strapdown airborne gravimeter, and comparing with the results from GT-1A airborne gravimeter which was on the same airplane with the new gravimeter, the difference using the Kalman smoothing filtering method is 0.6mGal. The accuracy of airborne measurement data processing using the cascaded method is better than the Kalman smoothing filtering and window function FIR low pass filtering method in some local details.Kalman smoothing filtering method and cascaded method of low pass Butterworth and Kalman smoothing filtering are given for the gravity data processing based on the domestic new air-sea gravimeter with a three axis inertial stabilized platform, The Kalman filtering state equations and observation equations are established. By calculating the gravity anomaly on repeated lines, the internal accord accuracy is under 0.5mGal. The cascaded method of Butterworth and Kalman smoothing filtering is better than the Kalman smoothing filtering and the Butterworth low pass filtering method.The data processing software for the domestic new strapdown airborne gravimeter and the air-sea gravimeter with a three axis inertial stabilized platform is designed and implemented. The software includes data preprocessing, GPS data solving, inertial/GPS integrated navigation, gravity anomaly solving, results analysis and evaluation and so on. It has not only the capabilities of gravity data processing, analyzing and displaying, but is also easy to operate and expanded. The software has an important reference and application value of domestic airborne gravity measurement data processing.