隨著科技的進步與蓬勃發展，人們對於衛星導航服務品質的需求也日漸增高，對於衛星導航的使用者而言，其最為詬病的便是因遮蔽效應而導致衛星導航服務的中斷，或是因受到多路徑效應等衛星觀測量粗差的影響而導致衛星導航服務品質不佳。然而，由中國自主研發的北斗衛星導航系統 (BeiDou Navigation Satellite System, BDS) 已於2012年底完成區域性系統的建置，並由14顆運行的衛星組網，提供服務給亞太地區的使用者，且由於BDS佈署了5顆地球靜止軌道衛星及5顆傾斜地球同步軌道衛星，故對於台灣的使用者而言，BDS的平均可視衛星數目儼然已成為全球導航衛星系統 (Global Navigation Satellite System, GNSS) 之首，有鑑於此，以及GPS與BDS間之高度兼容性與互操作性，本研究嘗試將GPS與BDS進行整合，並提出了偵錯與整合之方法，以期能改善衛星導航之服務品質。

在使用GNSS的時候常因人為、環境或系統本身的因素而導致衛星觀測量產生粗差，而為了處理觀測量粗差對於衛星導航之服務品質的不良影響，本研究使用Data Snooping來進行衛星觀測量粗差的偵測與剔除；再者，雖然將GPS與BDS整合後可增進其衛星幾何強度，但由於GPS與BDS為兩異質性之系統，因此若僅單純地使用等權或固定權比例的方式來整合GPS與BDS，將無法精確地反映GPS與BDS觀測量本身的實際精度，且整合之成果並不理想，故本研究使用Helmert方差分量估計來計算GPS與BDS觀測量之權比例，使兩異質的系統能更自動化且妥善地結合。

本研究使用連續接收約31個小時的GPS以及BDS雙頻觀測資料，以進行GPS/BDS整合式系統之單點定位，且為了深入地探討GPS/BDS整合式系統之效能，本研究藉由設定衛星截仰角的方式來模擬各種觀測條件，最後再透過衛星可視性、衛星幾何強度、內部可靠性、外部可靠性以及導航性能需求中的精確度、完整性、連續性以及可用性等性能指標，分析及評估GPS/BDS整合系統之效能，並將其與單一導航衛星系統之成果進行比較。

研究成果顯示，本研究用以進行偵錯之方法，可有效地偵測並排除觀測量粗差，使得衛星導航保有其正常之服務品質，且相較於使用單一的導航衛星系統，GPS/BDS整合式系統更可克服觀測量粗差對衛星導航服務品質之不良影響；再者，藉由本研究所提出之整合方法，GPS/BDS整合式系統將可透過改正數資訊，自動化地求得GPS與BDS間之精確的權比例，使其在衛星幾何強度與觀測量誤差間取得權衡，除了可更妥善地整合兩異質性的GPS與BDS外，其整合後之定位精確度亦可優於GPS單系統，尤其當使用者處於非空曠的觀測環境時，GPS/BDS整合式系統相對於GPS單系統之定位精確度的改善程度可達約70%至95%，除此之外，GPS/BDS整合式系統在水平與垂直方向的可用性也可提高約0.31至0.84與0.39至0.49，由此可知，GPS/BDS整合式系統克服遮蔽效應之影響的能力比單系統要來得好。

Chinese BeiDou Navigation Satellite System (BDS) has been established and composed of 14 operational satellites for providing navigation service in Asia-Pacific region. To the users in Taiwan, the number of visible BDS satellites is much more than other GNSS’s in average. In consideration of above reasons, the high compatibility and interoperability between GPS and BDS, we try to integrate widely used GPS and emerging developed BDS for better service quality of satellite navigation in this research.

In this research, we use dual-frequency pseudorange observation data for GPS/BDS single point positioning and simulate various observational conditions by adjusting satellite cut-off elevation angles. In the calculating process, we use data snooping for fault detection and exclusion (FDE), moreover, we use Helmert variance component estimation (VCE) to integrate these two heteroskedastic systems, so called GPS and BDS. The experimental results show that blunders can be detected and excluded efficiently by the FDE method used in this researchy, especially for GPS/BDS integrated system due to higher reliability, which can better prevent the bad effect from blunders. Furthermore, the weight ratio between GPS and BDS can be automatically calculated by Helmert VCE through the residual information for better integration. Comparing with GPS-only, when the user is not at spacious environment, the accuracy of GPS/BDS integrated system can be improved about 70% to 95%, the availability can be enhanced about 0.31 to 0.84 and 0.39 to 0.49 for horizontal and vertical directions, respectively.

Angrisano A., Gaglione S., Gioia C. (2013) Performance assessment of GPS/GLONASS single point positioning in an urban environment. Acta Geodaetica et Geophysica, 48 (2):149-161.
Baarda W. (1967) Statistical concepts in geodesy. Rijkscommissie voor Geodesie, Delft, Netherland.
Baarda W. (1968) A testing procedure for use in geodetic networks. Rijkscommissie voor Geodesie, Delft, Netherland.
Barker B.C., Betz J.W., Clark J.E., Correia J.T., Gillis J.T., Lazar S., Rehborn K.A., Straton III J.R. Overview of the GPS M code signal. In: Proceedings of the ION National Technical Meeting 2000, Anaheim, USA, January 26-28, 2000. pp. 542-549.
Bonhoure B., Vanschoenbeek I., Boschetti M., Legenne J. GPS-Galileo urban interoperability performance with the GPS-Galileo time offset. In: Proceedings of the ION GNSS 2008, Savannah, USA, September 16-19, 2008. pp. 971-981.
Brinker R.C., Minnick R. (1995) The surveying handbook. Chapman & Hall, New York, USA.
Brown R.G. (1992) A baseline GPS RAIM scheme and a note on the equivalence of three RAIM methods. Navigation, 39 (3):301-316.
Chen P., Wen H., Cheng Y., Wang H. (2009) Parameters of the CGCS2000 ellipsoid and comparisons with GRS80 and WGS84. Acta Geodaetica et Cartographica Sinica, 38 (3):189-194.
Chu F., Yang M. (2014) GPS/Galileo long baseline computation: method and performance analyses. GPS solutions, 18 (2):263-272.
Clinton B. (2000) Statement by the president regarding the united states’ decision to stop degrading global positioning system accuracy. Office of the Press Secretary, The White House, Washington, DC, USA.
CSNO (2013a) BeiDou navigation satellite system open service performance standard. China Satellite Navigation Office, Beijing, China.
CSNO (2013b) BeiDou navigation satellite system signal in space interface control document. China Satellite Navigation Office, Beijing, China.
CSNO (2013c) Report on the development of BeiDou (COMPASS) navigation satellite system. China Satellite Navigation Office, Beijing, China.
Cui X., Yu Z., Tao B. (2009) General surveying adjustment, 2 edition. The Publishing House of Wuhan University, Wuhan, China.
DeCleene B. Defining pseudorange integrity-overbounding. In: Proceedings of the ION GPS 2000, Salt Lake City, USA, September 19-22, 2000. pp. 1916-1924.
Dellago R., Detoma E., Luongo F. Galileo-GPS interoperability and compatibility: a synergetic viewpoint. In: Proceedings of the ION GPS/GNSS 2003, Portland, USA, September 9-12, 2003. pp. 542-548.
Deng C., Tang W., Liu J., Shi C. (2013) Reliable single-epoch ambiguity resolution for short baselines using combined GPS/BeiDou system. GPS Solutions, 18 (3):375-386.
Dierendonck A., Hegarty C. (2000) The new L5 civil GPS signal, GPS World, 11 (9):64-71.
DoD (2008) Global positioning system standard positioning service performance standard. Department of Defense, Washington, DC, USA.
DOD, DHS, DOT (2012) Federal radionavigation plan. Department of Defense, Department of Homeland Security, Department of Transportation, Springfield, USA.
Essen L., Froome K. (1951) The refractive indices and dielectric constants of air and its principal constituents at 24,000 Mc/s. Proceedings of the Physical Society, 64 (10):862-875.
FAA (2014) Global positioning system (GPS) standard positioning service (SPS) performance analysis report. Federal Aviation Administration, Washington, DC, USA.
Feng Y. (2003) Combined Galileo and GPS: a technical perspective. Journal of Global Positioning Systems, 2 (1):67-72.
Fontana R., Latterman D. GPS modernization and the future. In: Proceedings of the IAIN World Congress and the 56th AM of the ION, San Diego, USA, June 26-28, 2000. pp. 222-231.
Fontana R.D., Cheung W., Novak P.M., Stansell T. The new L2 civil signal. In: Proceedings of ION GPS 2001, Salt Lake City, USA, September 11-14, 2001. pp. 617-631.
Georgiadou Y., Doucet K.D. (1990) The issue of selective availability, GPS World, 1 (5):53-56.
Gleason S., Gebre-Egziabher D. (2009) GNSS applications and methods. Artech House, Norwood, USA.
Groves P.D. (2013) Principles of GNSS, inertial, and multisensor integrated navigation systems. Artech House, Norwood, USA.
Han C., Yang Y., Cai Z. (2011) BeiDou navigation satellite system and its time scales. Metrologia, 48 (4):S213-S218.
Harrington P. (2008) GPS program update. Paper presented at the IGG expert meeting on GNSS, Montreal, Canada, July 15.
Hawkins D.M. (1980) Identification of outliers. Chapman and Hall, New York, USA.
He H., Li J., Yang Y., Xu J., Guo H., Wang A. (2013) Performance assessment of single- and dual-frequency BeiDou/GPS single-epoch kinematic positioning. GPS Solutions, 18 (3):393-403.
Hegarty C.J., Chatre E. (2008) Evolution of the global navigation satellite system (GNSS). IEEE, 96 (12):1902-1917.
Hein G. (2006) GNSS interoperability: achieving a global system of systems or does everything have to be the same, Inside GNSS, 1 (1):57-60.
Hofmann-Wellenhof B., Lichtenegger H., Wasle E. (2008) GNSS–global navigation satellite systems: GPS, GLONASS, Galileo, and more. Springer-Verlag Wien, New York, USA.
Hopfield H. (1969) Two‐quartic tropospheric refractivity profile for correcting satellite data. Journal of Geophysical research, 74 (18):4487-4499.
Hudnut K.W., Titus B. (2004) GPS L1 civil signal modernization (L1C). Final Report of Interagency GPS Executive Board Stewardship Project #204.
ICAO (2007) International Standards and Recommended Practices, Annex 10 to the Convention on International Civil Aviation, Radio Navigation Aids. International Civil Aviation Organization, Montreal, Canada.
ICAO (2012) Global navigation satellite system (GNSS) manual. International Civil Aviation Organization, Montreal, Canada.
Jan S.-S., Lu S.-C. (2010) Implementation and evaluation of the WADGPS system in the Taipei flight information region. Sensors, 10 (4):2995-3022.
Kaplan E.D., Hegarty C.J. (2005) Understanding GPS: principles and applications, 2 edition. Artech house, Norwood, USA.
Kelly R., Davis J. (1994) Required navigation performance (RNP) for precision approach and landing with GNSS application. Navigation, 41 (1):1-30.
Koch K.-R. (1999) Parameter estimation and hypothesis testing in linear models, 2 edition. Springer, Germany.
Kuusniemi H. (2005) User-level reliability and quality monitoring in satellite-based personal navigation. Institute of Digital and Computer Systems, Tampere University of Technology, Finland.
Langley R.B. (1991) The mathematics of GPS, GPS World, 2 (7):45-50.
Leick A. (2004) GPS satellite surveying, 3 edition. John Wiley & Sons, New Jersey, USA.
Li D., Yuan X. (2002) Error processing and reliability theory, 2 edition. The Publishing House of Wuhan University, Wuhan, China.
Li H., Dang Y., Bei J., Yang F. (2013) Research on spatiotemporal unification of BDS/GPS/GLONASS multi-mode fusion navigation and positioning. Geodesy and Geodynamics, 33 (4):73-78.
Luo X., Cai C. (2013) Accuracy assessment of combined GPS/Galileo single point positioning. Geodesy and Geodynamics, 33 (3):136-140.
Malys S., Slater J. Maintenance and enhancement of the world geodetic system 1984. In: Proceedings of the ION GPS 1994, Salt Lake City, USA, September 20-23, 1994. pp. 17-24.
Meng W., Liu E., Han S., Yu Q. (2012) Research and development on satellite positioning and navigation in China. IEICE Transactions on Communications, E95.B (11):3385-3392.
Misra P., Enge P. (2006) Global positioning system: signals, measurements and performance, 2 edition. Ganga-Jamuna Press, Lincoln, USA.
Montenbruck O., Hauschild A., Steigenberger P., Hugentobler U., Teunissen P., Nakamura S. (2012) Initial assessment of the COMPASS/BeiDou-2 regional navigation satellite system. GPS Solutions, 17 (2):211-222.
Moudrak A., Konovaltsev A., Furthner J., Hornbostel A., Hammesfahr J. GPS Galileo time offset: How it affects positioning accuracy and how to cope with it. In: Proceedings of the ION GNSS 2001, Long Beach, CA, September 11-14, 2001. pp. 660-669.
Ochieng W., Sheridan K., Han X., Cross P., Lannelongue S., Ammour N., Petit K. (2001) Integrity performance models for a combined Galileo/GPS navigation system. Journal of Geospatial Engineering, 3 (1):21-32.
Parkinson B.W., Axelrad P. (1988) Autonomous GPS integrity monitoring using the pseudorange residual. Navigation, 35 (2):255-274.
Parkinson B.W., Gilbert S.W. (1983) NAVSTAR: global positioning system—ten years later. IEEE, 71 (10):1177-1186.
Parkinson B.W., Spilker J.J. (1996) Global positioning system: theory and applications. American Institute of Aeronautics and Astronautics, Washington, DC, USA.
Pellerin C. (2006) United states updates global positioning system technology: new GPS satellite ushers in a range of future improvements, http://iipdigital.usembassy.gov/.
Perino D. (2007) Statement by the press secretary. Office of the Press Secretary, White House, Washington, DC, USA.
Petovello M. (2013) Calculating time offsets: how do you deal with timing differences between GNSSs? , Inside GNSS, 8 (3):32-37.
Ran C. (2011) Development of BeiDou navigation satellite system. Paper presented at the Proceedings of the 6th ICG, Tokyo, Japan, September 5-9.
Ran Y., Hu X., Liu Y., Ke T., Tang Z. (2010) Compatibility analysis of Compass navigation signals. SCIENCE CHINA Physics, Mechanics & Astronomy, 40 (5):676-684.
RTCA (2006) Minimum operational performance standards for global positioning system/wide area augmentation system airborne equipment (DO-229D). Radio Technical Commission for Aeronautics, Washington, DC, USA.
Saastamoinen J. (1972) Atmospheric correction for the troposphere and stratosphere in radio ranging satellites. Geophysical Monograph Series, 15:247-251.
Satirapod C., Rizos C., Wang J. (2001) GPS single point positioning with SA off: how accurate can we get? Survey Review, 36 (282):255-262.
Schaffrin B. (1997) Reliability measures for correlated observations. Journal of Surveying Engineering, 123 (3):126-137.
Seeber G. (2003) Satellite geodesy: foundations, methods, and applications, 2 edition. Walter de Gruyter, Berlin, Germany.
Seynat C., Kealy A., Zhang K. (2004) A performance analysis of future global navigation satellite systems. Journal of Global Positioning Systems, 3 (1-2):232-241.
Shrestha S.M. (2003) Investigations into the estimation of tropospheric delay and wet refractivity using GPS measurements. University of Calgary, Calgary, Canada.
Smith E.K., Weintraub S. (1953) The constants in the equation for atmospheric refractive index at radio frequencies. Proceedings of the IRE 1953, 41 (8):1035-1037.
Sun F., Liu S., Zhu X., Men B. (2012) Research and progress of BeiDou satellite navigation system. Science China Information Sciences, 55 (12):2899-2907.
Teunissen P. Quality control in integrated navigation systems. In: Position Location and Navigation Symposium (PLANS), Las Vegas, USA, 1990. IEEE, pp. 158-165.
Teunissen P. (2000) Testing theory: an introduction. Delft University Press, Delft, Netherland.
Teunissen P.J.G., Odolinski R., Odijk D. (2013) Instantaneous BeiDou+GPS RTK positioning with high cut-off elevation angles. Journal of Geodesy, 88 (4):335-350.
UNOOSA (2010) Current and planned global and regional navigation satellite systems and satellite-based augmentations systems. United Nations Office for Outer Space Affairs, New York, USA.
Vanschoenbeek I., Bonhoure B., Boschetti M., Legenne J. (2007) GNSS time offset: effects on GPS-Galileo interoperability performance, Inside GNSS, 2 (6):60-70.
Wallner S., Avila-Rodriguez J., Hein G. (2006) Interference computations between several GNSS systems. ESA Navitec:11-13.
Walter T., Enge P. Weighted RAIM for precision approach. In: Proceedings of the ION GPS 1995, Palm Springs, USA, September 12-15, 1995. pp. 1995-2004.
Wang J., Knight N.L., Lu X. (2011) Impact of the GNSS time offsets on Positioning Reliability. Journal of Global Positioning Systems, 10 (2):165-172.
Wei Z. (2008) China geodetic coordinate system 2000 and its comparison with WGS84. Journal of Geodesy and Geodynamics, 28 (5):1-5.
Wells D.E., Beck N., Delikaraoglou D., Kleusberg A., Krakiwsky E., Lachapelle G., Langley R., Nakiboglu M., Schwarz K.-P., Tranquilla J. (1999) Guide to GPS positioning. Department of Geodesy and Geomatics Engineering, University of New Brunswick, Fredericton, Canada.
Wong R.F., Rollins C.M., Minter C.F. Recent updates to the WGS84 reference frame. In: Proceedings of the ION GNSS 2012, Nashville, USA, September 17-21, 2012. pp. 1164-1172.
Xu G. (2007) GPS: theory, algorithms and applications, 2 edition. Springer, New York, USA.
Yang Y. (2009) Chinese geodetic coordinate system 2000. Chinese Science Bulletin, 54 (15):2714-2721.
Yang Y. (2010) Progress, contribution and challenges of Compass/Beidou satellite navigation system. Acta Geodaetica et Cartographica Sinica, 39 (1):1-6.
Yu W., Dai W., Ding X., Yang W., Gao X. Stochastic model of GPS/BD combined standard single point positioning. In: Proceedings of the China Satellite Navigation Conference (CSNC) 2012, Guangzhou, China, May 15-19, 2012. Springer Berlin Heidelberg, pp. 325-334.
Zhao C., Ou J., Yuan Y. (2005) Positioning accuracy and reliability of Galileo, integrated GPS-Galileo system based on single positioning model. Chinese Science Bulletin, 50 (12):1252-1260.
Zhou S., Cao Y., Zhou J., Hu X., Tang C., Liu L., Guo R., He F., Chen J., Wu B. (2012) Positioning accuracy assessment for the 4GEO/5IGSO/2MEO constellation of COMPASS. Science China Physics, Mechanics and Astronomy, 55 (12):2290-2299.
Zhu C. (2012) Algorithm research and experimental analysis for GNSS multi-constellation integrated positioning. Paper presented at the the IAIN World Congress 2012, Cairo, Egypt, October 1-3.