Abstract
The Open Source GNSS Reference Server (OSGRS) exploits the GNSS Reference Interface Protocol (GRIP) to provide assistance data to GPS receivers. Assistance can be in terms of signal acquisition and in the processing of the measurement data. The data transfer protocol is based on Extensible Mark-up Language (XML) schema. The first version of the OSGRS required a direct hardware connection to a GPS device to acquire the data necessary to generate the appropriate assistance. Scenarios of interest for the OSGRS users are weak signal strength indoors, obstructed outdoors or heavy multipath environments.
This paper describes an improved version of OSGRS that provides alternative assistance support from a number of Global Navigation Satellite Systems (GNSS). The underlying protocol to transfer GNSS assistance data from global casters is the Networked Transport of RTCM (Radio Technical Commission for Maritime Services) over Internet Protocol (NTRIP), and/or the RINEX (Receiver Independent Exchange) format. This expands the assistance and support model of the OSGRS to globally available GNSS data servers connected via internet casters. A variety of formats and versions of RINEX and RTCM streams become available, which strengthens the assistance provisioning capability of the OSGRS platform.
The prime motivation for this work was to enhance the system architecture of the OSGRS to take advantage of globally available GNSS data sources. Open source software architectures and assistance models provide acquisition and data processing assistance for GNSS receivers operating in weak signal environments. This paper describes test scenarios to benchmark the OSGRSv2 performance against other Assisted-GNSS solutions. Benchmarking devices include the SPOT satellite messenger, MS-Based & MS-Assisted GNSS, HSGNSS (SiRFstar-III) and Wireless Sensor Networks Assisted-GNSS. Benchmarked parameters include the number of tracked satellites, the Time to Fix First (TTFF), navigation availability and accuracy.
Three different configurations of Multi-GNSS assistance servers were used, namely Cloud-Client-Server, the Demilitarized Zone (DMZ) Client-Server and PC-Client-Server; with respect to the connectivity location of client and server. The impact on the performance based on server and/or client initiation, hardware capability, network latency, processing delay and computation times with their storage, scalability, processing and load sharing capabilities, were analysed.
The performance of the OSGRS is compared against commercial GNSS, Assisted-GNSS and WSN-enabled GNSS devices. The OSGRS system demonstrated lower TTFF and higher availability.
References
[1] 911 Services, Public Safety and Homeland Security Bureau, (2009), viewed 15 June 2010, http://www.fcc.gov/pshs/services/911-services/.Search in Google Scholar
[2] Apache common libraries, viewed and downloaded 11 Sept 2010, http://commons.apache.org.Search in Google Scholar
[3] Bahl P/ & Padmanabhan, V., RADAR: An In-Building RF-based User Location and Tracking System, Microsoft Research, Infocom 2000, Volume: 2, On page(s): 775-784 vol.2, 26 Mar 2000.Search in Google Scholar
[4] Networked Transport of RTCM Protocol, NTRIP, viewed 15 Aug 2010, http://igs.bkg.bund.de/index_NTRIP.htmSearch in Google Scholar
[5] Dammalage T., Srinuandee P., Samarakoon L., Susaki J., Srisahakit T., Potential Accuracy and Practical Benefits of NTRIP Protocol Over Conventional RTK and DGPS Observation Methods, Map Asia 2006.Search in Google Scholar
[6] Diggelen F. V., AGPS: Assisted GPS, GNSS and SBAS, NavtechGPS, Springfield, VA, (2009), 31-43.Search in Google Scholar
[7] EUREF (2007), Global NTRIPServers and Casters listing viewed Aug 2010, http://www.euref-ip.net/home.Search in Google Scholar
[8] Featherstone W. E., and Kuhn, M., Height Systems and Vertical Datums: A Review in the Australian Context, Journal of Spatial Science 51(1) (2006), 21-42.10.1080/14498596.2006.9635062Search in Google Scholar
[9] 911 Wireless Services, http://www.fcc.gov/pshs/services/911-services/, viewed 6 July 2010.Search in Google Scholar
[10] Garin L., Wireless Sensor Network-Based Distributed GNSS. Receiver Architecture for Infrastructure Monitoring, UCGE Reports Number 20302, Positioning, Location and Navigation (PLAN), Jan 2010.Search in Google Scholar
[11] Gurtner W., The Receiver Independent Exchange Format, RINEX, Version 3.00, Astronomical Institute, University of Bern, November 28, 2007 www.epncb.oma.be/ftp/data/format/rinex300.pdfSearch in Google Scholar
[12] Harper N., Server-Side GPS and Assisted-GPS in Java (2009), Artech House Publishers.Search in Google Scholar
[13] Janssen V., Understanding Coordinate Reference Systems, Datums and Transformations, International Journal of Geoinformatics 5(4), (2009), 41-53.Search in Google Scholar
[14] Krumm J., Williams L., Smith G., SmartMoveX on a graph—an inexpensive Active Badge Tracker, UbiComp 2002 LaMarca A., J. Hightower, I. Smith, and S. Consolvo (2005) “Self-Mapping in 802.11 Location Systems”, Intel Research Seattle, Lecture Notes in Computer Science, 2005, Springer, ISSN 0302-9743.Search in Google Scholar
[15] Lorincz K. & Welsh M., MoteTrack: A Resilient, Uncentralized Approach to RF-Based Location Tracking, Springer Personal and Ubiquitous Computing, Special Issue on Location and Context-Awareness, October 2006. ISSN: 1617-4909 (Print) 1617-4917 2006.Search in Google Scholar
[16] Mautz R., Overview of Current Indoor Positioning Systems, Geodesy and Cartography, Versita, 2009.10.3846/1392-1541.2009.35.18-22Search in Google Scholar
[17] Murata M., St. Laurent S., Kohn D., XML Media Types (RFC 3023), (2001). http://www.rfceditor.org/rfc/rfc3023.txt, viewed 20 Dec 2010.Search in Google Scholar
[18] Open Mobile Alliance, Secure User Plane Location architecture v1.0 June 2007, OMA-AD-SUPLV1_0-20070615-A.Search in Google Scholar
[19] Open Mobile Alliance, Secure User Plane Location Architecture v2.0, Sep2010, OMA-AD-SUPL-V2_0-20110527-C.Search in Google Scholar
[20] Open Mobile Alliance, Secure User Plane Location Architecture v3.0, May2011, OMA-AD-SUPL-V3_0-20110308-C.Search in Google Scholar
[21] Receiver Independent Exchange Format (2007), RINEX, viewed 25 Jan 2011, http://gps.wva.net/html.common/rinex.html.Search in Google Scholar
[22] RFC3023 (2001), XML media types, http://tools.ietf.org/html/rfc3023, viewed 30 Jun 2010 and 20 July 2012.Search in Google Scholar
[23] RTCM Special Committee 104 on Global Navigation Satellite Systems (GNSS) Service (2001) RTCM10402.3, RTCM Recommended Standards for Differential GNSS (Global Navigation Satellite Systems) Service, Version 2.3, The Radio Technical Commission for Maritime Services, Arlington.Search in Google Scholar
[24] Sarwar, Ali Hassan, Performance of location determination techniques in weak signal environments employing reference server, caster, cellular and sensor networks and multiple assisted global navigation satellite systems, School of Surveying and Geospatial Engineering, Faculty of Engineering, University of New South Wales, (2013).Search in Google Scholar
[25] Sarwar A., Glennon E. & Rizos C., Proposing a MultiGNSS Assisted GNSS-Concept and Performance, IGNSS Symposium, 15-17 Nov 2011.Search in Google Scholar
[26] Sarwar A., Glennon E. & Rizos C., RRLP (LPP and LPPe) Based Open Source Mobile Multi-GNSS Assisted GNSS Assistance Model, IPIN, 13-15 Nov 2012.Search in Google Scholar
[27] Sarwar A., Glennon E. & Rizos C., Test results of a Wireless Sensor Networks Assisted Global Navigation Satellite System (WSN-AGNSS), International Global Navigation Satellite Systems Society IGNSS Symposium 2011.Search in Google Scholar
[28] SiRFstarIII, High Performance, Low Power GPS Solution, SiRF Chips + GPS (2007), viewed 13 Oct 2007, http://www.sirf.com/products/GSC3LPProductInsert.pdf.Search in Google Scholar
[29] Turunen S., Network Assistance, what will new GNSS signals bring to it, Inside GNSS, Spring 2007.Search in Google Scholar
[30] XML parser libraries, viewed and downloaded 10 Sept 2010, http://xerces.apache.org.Search in Google Scholar
[31] Yan T., Mumford P., Dempster A. G., Rizos C., Hoang N., & Fernand, M., Open source GNSS reference server, 20th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Fort Worth, Texas, 25-28 September, 2007, 2224-2229.Search in Google Scholar
[32] Wirola L., Location Standards Driving mass market LCS adoption, Location and Commerce, Nokia, ICL-IGNSS 2011, 29 Jun 2011, http://www.icl-gnss.org/2011/index.phpSearch in Google Scholar
© 2015 Walter de Gruyter GmbH, Berlin/Boston
Articles in the same Issue
- Frontmatter
- Research Articles
- Comparison between multi-constellation ambiguity-fixed PPP and RTK for maritime precise navigation
- Performance of the High Sensitivity Open Source Multi-GNSS Assisted GNSS Reference Server.
- An Improved Between-Satellite Single-Difference Precise Point Positioning Model for Combined GPS/Galileo Observations
- Accuracy of unmodified Stokes’ integration in the R-C-R procedure for geoid computation
- Outlier Detection by means of Monte Carlo Estimation including resistant Scale Estimation
Articles in the same Issue
- Frontmatter
- Research Articles
- Comparison between multi-constellation ambiguity-fixed PPP and RTK for maritime precise navigation
- Performance of the High Sensitivity Open Source Multi-GNSS Assisted GNSS Reference Server.
- An Improved Between-Satellite Single-Difference Precise Point Positioning Model for Combined GPS/Galileo Observations
- Accuracy of unmodified Stokes’ integration in the R-C-R procedure for geoid computation
- Outlier Detection by means of Monte Carlo Estimation including resistant Scale Estimation