傳統重力測量利用重力儀量測特定點的重力值，需要很多人力而且耗時，為了克服這些缺點，更方便測得重力，其他形式的重力測量慢慢發展，例如車載、船載、空載重力測量。車載移動式SINS/GNSS整合系統與傳統重力儀相比，比較有效率，人力和花費也都較省，而與空載重力測量相比，車載移動式整合系統可以提供高精度與較小空間解析度的重力場資訊。此外，這些重力資料可以應用在其他科學研究，例如決定大地水準面、調查造山運動、研究海底構造、質量不平衡的地方等等。
在本研究中使用儀器包括一個導航等級的IMU搭配GNSS接收儀。導航等級IMU中，陀螺儀和加速度計的偏差分別小於0.002deg/h 和10ug (戰術等級的IMU，陀螺儀和加速度計的偏差分別小於0.1deg/h和100ug)。本研究規劃了兩個實驗，一個是收集台南到泰安休息站的高速公路的資料，另一個則是從仁德出發，沿著國道一號→快速道路82→國道三號→快速道路86的路線繞一圈，最後回到仁德，同一路線會重複跑兩到三次，因此我們可以針對重力資訊的重複性作分析。實驗分成靜態及動態兩種模式。靜態測量時，車子沿路會停五分鐘作ZUPT，利用ZUPT的資料來檢驗GNSS算出來的加速度以及重力擾動是否合理，目前靜態重力資料的精度可在10mgal內。動態資料中還無法求得合理重力擾動值，所以希望未來可以藉由訊號處理技術得到改善。

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.

References
1.Chiu, C.J. (2002): A study of the INS/GPS airborne gravimetry-the direct difference approach, Master thesis, National Cheng Kung University

2.Chuang, F.F. (2004): A study on kalman filter for determining gravity field from airborne GPS/INS measurement data, Master thesis, National Cheng Kung University

3. Shih, H.C. (2004): Measurement system of airborne gravity, Master thesis, National Chiao Tung University

4.Li, T.Y. (2005): Determination of aircraft velocity and acceleration with GPS for airborne gravimetry, Master thesis, National Cheng Kung University

5.Hu, Z.Y. (2008): The utilization of a low cost tightly coupled INS/GPS integrated system for seamless land vehicle navigation, Master thesis, National Cheng Kung University

6.Bell, R.E., Coakley, B.J., Blankenship, D.D., Hodge, S.M., Brozena, J.M. and Jarvis, J. (1992): Airborne gravity from a light aircraft: CASERTZ 1990–91, In: Yoshida, Y. (ed) Recent Progress in Antarctic Earth Science, Terrapub, Tokyo, pp. 571–577

7.Brozena, J.M. (1992): The Greenland aerogeophysics project: airborne gravity, topographic and magnetic mapping of an entire continent, In: Colombo, O. (ed) From Mars to Greenland, Proceedings of the IAG Symposia 110. Springer, New York, pp. 203–214

8.Brozena, J.M., Peters, M.F. and Salman, R. (1996): Arctic airborne gravity measurement program. In: Segawa, J., Fujimoto, H. and Okubu, S. (eds) Gravity, Geoid and Marine Geodesy, Proceedings of the IAG Symposia 117, Springer, Heidelberg, pp. 131–138

9.Bruton, A.M., Glennie, C.L. and Schwarz, K.P. (1999): Differentiation for high-precision GPS velocity and acceleration determination, GPS solutions, Vol 2, pp.7-21

10.Bruton, A.M. (2000): Improving the accuracy and resolution of SINS/DGPS on airborne gravimetry, UCGE reports, Number 20145

11.Bar-Shalom, Y., Lin, X., Kirubarajan, T. and Xiaorong Li (2001): Enhanced accuracy GPS navigation using the interacting multiple model estimator, Aerospace Conference, IEEE Proceedings, Vol4

12.Chiang, K.W. (2004): INS/GPS Integration Using Neural Networks for Land Vehicular Navigation Applications, UCGE Reports, Number 20209, Department of Geomatics Engineering, the University of Calgary, Canada

13.Chiang, K.W., Chang, H.W., Li, C.Y. and Huang Y.W. (2009): An Artificial Neural Network Embedded Position and Orientation Determination Algorithm for Low Cost MEMS INS/GPS Integrated Sensors, Sensors, Vol 9, issue 4, EISSN 1424-8220

14.Chiang, K.W., Trung Duong T., Liao, J.K., Chang C.C., Cai J.M. and Huang, S.C. (2012): On-Line Smoothing for an Integrated Navigation System with Low-Cost MEMS Inertial Sensors, Sensors, Vol 12, issue 12, EISSN 1424-8220

15.Elieff, S. and Ferguson, S. (2008): Establishing the “air truth” from 10 years of airborne gravimeter data, First Break, 26, 73–77, November 2008

16.El-Sheimy, N. (2000): An Expert Knowledge GPS/INS System for Mobile Mapping and GIS Applications, Proceeding of the 2000 National Technical Meeting of the Institute of Navigation, January 26-28 ,2000, California, USA, CD

17.Gelb, A. (1974): Applied optimal Estimation, The M.I.T. Press, Massachusetts Institute of Technology , Carnbridge, Massachusetts and London, England,

18.Gerlach, Ch., Dorobantu, R., and Rothacher, M. (2005): Results of a combined INS/GPS experiment for geodetic application, Navigation, Vol 53, pp.31-47

19.Gerlach, Ch., Dorobantu, R., Ackermann, Ch. and Boedecker, G. (2010): Preliminary Results of a GPS/INS Airborne Gravimetry Experiment over the German Alps, Graity, Geoid and Earth Observation, International Association of Geodesy Symposia 135, Springer-Verlag Berlin Heidelberg

20.Hannah, J. (2001): Airborne gravimetry: A status report, Department of Surveying, University of Otago, PO Box 56, Dunedin

21.Hofmann-Wellenhof, B., Lichtenegger, H. and Wasle, E. (2008): GNSS–Global Navigation Satellite Systems, Springer Science & Business Media , Germany

22.Jekeli, C. and Garcia, R. (1997): GPS phase accelerations for moving-base vector gravimetry, Journal of Geodesy, Vol. 71, pp. 630-639

23.Jekeli, C. and Kwon, J.H. (2001): A new approach for airborne vector gravimetry using GPS/INS, Journal of Geodesy, 690-700

24.Jekeli, C. and Li, X. (2006): INS/GPS vector gravimetry along roads in western Montana, OSU Report, No. 477, Department. of Geodetic Science and Surveying, the Ohio State University, Columbus, Ohio 43210

25.Kalman, R.E. (1960): A New Approach to Linear Filtering and Prediction Problems, Transactions of the ASME– Journal of Basic Engineering, Vol. 82, Number Series D, pp. 35-45

26.Kennedy, S.L. (2002), Acceleration estimation from GPS carrier phases for airborne gravimetry, A thesis of the degree of master of science in geomatic engineering, University Calgary, Canada

27.Klingele, E., Halliday, M., Cocard, M. and Kahle, H.-G (1995): Airborne gravimetric survey of Switzerland, Vermessung, Photogrammetrie, Kulturtechnik, 4, pp. 248–253

28.Kreye, Ch., Hein, G.W. and Zimmermann B. (2004): Evaluation of airborne gravimetry integratin GNSS and strapdown INS observations, Gravity, Geoid and Space Missions, Session 2, pp 101-106, Germany

29.Li, X. and Jekeli, C. (2006): Ground-Vehicle INS/GPS Vector gravimetry assessment using repeated traverses in Montana, Division of Geodesy and Geospatial Science, School of Earth Sciences, The Ohio State University, Columbus, OH 43210-1398

30.Li, X. (2011): Strapdown INS/DGPS airborne gravimetry tests in the Gulf of Mexico, Journal of Geodesy, Vol. 85, Issue 9 , pp 597-605

31.Misra, P. and Enge, P. (2011): Global Positioning System: Signals, Measurements, and Performance, Revised Second Edition, Ganga-Jamuna Press, Lincoln, Massachusetts

32.Skaloud J., Bruton A.M, and Schwarz, K.P. (1999): Detection and Filtering of Short-Term (1/f) Noise in Inertial Sensors, Journal of The Institute of Navigation, Vol.46, No.2, pp 97-107

33.Schwarz, K.P. and Wei, M. (2000): INS/GPS Integration for Geodetic Applications, Lecture Notes ENGO 623, Department of Geomatics Engineering., The University of Calgary, Canada.

34.Shin, E.H. (2001): Accuracy of low cost INS/GPS for land applications, UCGE reports, Number 20156, Department of Geomatics engineering, The University of Calgary, Canada.

35.Williams, S. and MacQueen, J.D. (2001): Development of a versatile, commercially proven, and cost-effective airborne gravity system. The Leading Edge, vol. 20, issue 6, pp 651–654