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THEME 1: CORS OPERATIONS & HIGH-ACCURACY GNSS ALGORITHMS
Academic staff members
of the School of Surveying &
Spatial Information Systems, University of New South Wales, now
undertake research and teaching in areas beyond just the narrow field
of "satellite navigation and positioning" of the original
SNAP group of the 1990s, to also embrace what may be referred to as "earth observation" (geodesy, airborne and satellite remote sensing and imaging). To better describe the range of activities
in the fields of satellite and ground-based wireless positioning, our
research projects are grouped into several themes. Download
our SNAP Lab Research Directions document to see what we'll be
researching over the next few years. The SNAP Lab has also produced a Research
Brochure that explains the range of research topics being undertaken,
identifying opportunities for potential graduate students as well as
research collaboration with external partners. ...email
us for a hardcopy, or download
a PDF version.
Theme 1 deals with the general topics of navigation sensor data processing algorithms (principally those related to GPS/GNSS carrier phase data processing), and how permanent Continuously Operating Reference Station (CORS) receiver networks may be used to support high-accuracy GPS/GNSS positioning (and non-positioning) applications. SNAP Lab is:
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a developer of carrier phase data processing algorithms, for both baseline and network-modes, to support rapid (single-epoch) ambiguity resolution, including in real-time
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operates a research CORS network in the Sydney area to support next generation CORS services and products
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undertakes research into multi-GNSS algorithms and implications for high accuracy/integrity users
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operates a variety of GNSS hardware (all commercial brands of GNSS receivers), as well as being the only Australian organisation that operates a receiver capable of tracking the GIOVE-A satellite
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has developed, and operates, an Open Source GNSS Reference Server to support Assisted-GNSS users
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is a beta test site for Leica's SpiderNet software
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is a beta test site for NTRIP, and operates an NTRIP Caster
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is a participant in the IGS's Real-Time Pilot Project
Researchers at UNSW commenced investigations into GPS observation modelling and the development of data processing software in 1984. (Although SNAP publications are listed only since 1992, publications by Chris Rizos on GPS algorithms/software go back to 1984.) Over the years many algorithms have been developed by graduate students, staff and visiting researchers. However, no effort was made to develop a comprehensive suite of SNAP software. Bernie Hirsch, a former programmer within the School of Surveying, was working with Chris Rizos since the mid-1980s, and until his untimely death in December 1997. In 2002 a strategic decision was made to continue development of a suite of software for static and kinematic positioning, capable of both real-time and offline (post-processing) scenarios. This includes single baseline and network-based positioning and is now the fundamental software platform for future GNSS research. For a short history of SNAP's major achievements click here ... The SNAP Lab operates a range of GNSS receivers. The latest acquisitions were four Leica System 1200 GPS+Glonass receivers. The SNAP Lab also operates a GIOVE-A tracking receiver (on loan from DLR, Germany).
 Leica System 1200 receivers in the SNAP Lab |
 Septentrio GeNeRx receiver in the SNAP Lab with antenna installed on the roof of the Electrical Eng. Bld. on 4 February 2008 |
The primary focus of GPS studies at UNSW during the 1980s were the geodetic applications of the (then) new GPS space technology such as orbit determination and station network processing. ("GPS Geodesy" could claim to be the first civilian application of GPS, having its origins in the early 1980s with the development of carrier phase tracking receivers and software.) Many of these early GPS studies were related to fundamental challenges of algorithms and software, as academic geodesists the world over enthusiastically embraced GPS, and researched the modelling and algorithms relevant to the post-processing of GPS carrier phase data. However SNAP researchers were also engaged in geodetic applications such as the Bass Strait Regional Tide Gauge Survey, the Australian GPS Orbit Determination Pilot Project, and later studies related to volcano deformation monitoring in Indonesia. The software used for these studies was a combination of inhouse developed software, and "scientific" GPS software packages such as GAMIT and Bernese.
From the beginning of the 1990s geodesists at all Australian universities with surveying/geomatics departments were taking advantage of the GPS technology to address challenges such as the establishment of geodetic datums in different countries (particularly in the Australasian region), and even in Antarctica, as well as for geodynamic studies in areas of S.E. Asia and the Pacific. In addition, at this time the Geodesy Group within the Australian Surveying and Land Information Group (AUSLIG - now part of Geoscience Australia) was achieving impressive results. (The National Geospatial Reference System Project within GA continues to process GPS data on a daily basis to address global and regional geodetic problems.)
During the 1980s the focus of algorithm/software research was on fundamental GPS data modelling (e.g. undifferenced processing verses double-differencing), and the parameterisation of the "clock biases". The applications were related to static, geodetic uses such as orbit determination and station network processing. Later applications for surveying were considered, and by the early-mid-1990s the research focus was clearly on efficient/rapid carrier phase ambiguity resolution. Ultimately the geodetic or surveying (i.e. static) mode of carrier phase-based GPS positioning gave way to precise GPS navigation or "kinematic surveying".
In the mid-1990s the SNAP Lab made a strategic decision to withdraw from GPS geodesy research on the global or regional scale, and focus instead on very local geodetic applications such as volcano deformation, ground subsidence and structural monitoring. These "local" or "engineering" geodesy applications remain an important SNAP Lab research focus within Theme 2.
(1) Carrier Phase Algorithm Research
Graduate students who have made contributions to algorithm research for geodetic applications over the last two decades include: Bertrand Merminod, Don Grant, Penshan Hung, Mustafa Subari, Cliff Chu, David Lin, Shaowei Han, Horng-Yue Chen, Linlin Ge, Chalermchon Satirapod, Clement Ogaja, Craig Roberts, Volker Janssen and Tajul Musa. In fact much of the present day reputation of SNAP is based on the ground-breaking research undertaken in this area. For example, different positioning modes were investigated: rapid static, GPS traversing, network-based kinematic positioning, mixed dual-frequency/single-frequency receiver positioning, medium and long-range baseline estimation, GPS+Glonass positioning, and so on.
Graduate students who have made contributions to algorithm research for navigation (or "kinematic") applications include: Bertrand Merminod, Wan Fu, Shaowei Han, Liwen Dai, Michael Moore, Ben Soon, H.K. Lee and Bill Ely.
The functional and stochastic models of GPS measurements remain very important research topics even today. GPS data is increasingly combined with measurement data from Inertial Navigation Systems and Pseudolites, and will soon be augmented with new signals from other Global Navigation Satellite Systems (GNSSs) such as the EU's Galileo, Russia's Glonass and China's Compass, and regional space-based systems such as Japan's Quasi-Zenith Satellite System and the Indian Regional Navigation Satellite System (IRNSS). Hence it is vital that SNAP continues this tradition of algorithm research. However, algorithm research feeds back into software development, and hence there is close collaboration of research assistants such as Yong Heo and Thomas Yan with academic researchers, research associates and graduate students.
(2) GNSS CORS Research
Continuously Operating Reference Stations (CORS) of GNSS receivers currently support many high accuracy applications in surveying, mapping, navigation and geodesy. CORS networks are being established at an ever increasing rate around the world, and this infrastructure will be used for long-term geoscientific studies as well as provide the basis for GNSS-RTK (Real-Time Kinematic) positioning and augmentation services (including Assisted-GNSS or A-GNSS). From the 1980s the SNAP Lab has been a research leader into a new concept of survey-accuracy (cm-level) GPS positioning based on multiple CORS receivers. The standard mode of commercial GPS carrier phase-based positioning for surveying and mapping applications was the baseline approach, where one GPS receiver was located at a point of known coordinates and the second (‘rover’) receiver would have its coordinates determined relative to the fixed reference station. In this mode the longest practical baseline length was typically between 10-20km (and varied with ionospheric activity, satellite geometry, and the effects of other residual biases). In the "network mode" the CORS inter-receiver distances could be 50-70km, making it a much more economical technique for CORS coverage across large areas. Graduate students who have made contributions to network algorithm research include: Shaowei Han, Liwen Dai, Horng-Yue Chen and Tajul Musa.
In early-2003 the Department of Lands (NSW) initiated a project to “…establish a multi-reference differential GPS network capable of providing suitable equipped users with centimetre level position accuracy in real time across the greater Sydney metropolitan area…”. This network, which came to be known as “SydNet”, was also to be a test-bed for SNAP Lab research into CORS network-based algorithms, technologies and concepts. SydNet now consists of seven stations in the Sydney basin area plus four more regional stations at Bathurst, Newcastle, Nowra and Gouldburn, with plans for two more at Port kembla and Wyong in the 2008-09 financial year. Over the next few years the network will extend across the state of NSW. Testing of Leica’s SpiderNet and NTRIP/RTCM protocols and formats is an ongoing activity.
Seven sites within the SydNet CORS network in the Sydney basin. In addition UNSW hosts several CORS receivers, including a GIOVE-A tracking receiver.
The extension of SydNet, to eventually become “NSWNet”, is partly driven by the investment in GNSS CORS infrastructure as part of the Federal Government’s NCRIS (National Collaborative Research Infrastructure Strategy) Capability 5.13, Structure and Evolution of the Australian Continent, also known as AuScope. Over 100 new GNSS CORS will be established across Australia over the next three years.
Planned AuScope GNSS CORS receiver sites.
Current CORS real-time augmentation systems can be described as being “generation 1”, as the RTK services that are provided to a small number of subscribers on a “use-as-is” basis, without guarantee of service. CORS network hardware and software systems are going to face a number of challenges in the coming years, including the need to track new GNSS signals, generate new RTK correction services, integrate free real-time data streams from the International GNSS Service (IGS) (& other CORS networks), develop improved algorithms to support ultra-high accuracy geodetic applications, and develop new CORS-based services. All of these challenges will require a paradigm shift away from service providers being the government agencies that invest in the CORS infrastructure (receivers, communication links, servers, etc.) to a variety of new architectures and business models that can take advantage of the opportunities offered by improved CORS network infrastructure. The term “generation 2” has been suggested to describe this new paradigm. Research challenges range from designing the appropriate IT components and GNSS CORS receiver technology, and the new baseline and network algorithms utilising the new GNSS signals, new data processing models based on different configurations of CORS and user GNSS receivers, leading to new RTK services, delivered by a variety of new wireless communication links, incorporating new value-added services such as server-based processing, which more closely link RTK to real-time geodesy operations and fundamental geoscientific applications.
The current activities and challenges in Theme 1 can be summarised as:
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Stochastic & functional modelling research at SNAP was being conducted hand-in-hand with new carrier phase-based positioning techniques pioneered by Shaowei Han (1995-1997), based on dual-frequency measurements. Adaptive stochastic modelling was the "key" to very rapid (single-epoch) amibiguity resolution. In 2000, Jinling Wang joined SNAP as an ARC Postdoctoral Fellow, and continued research into stochastic modelling and ambiguity resolution for GPS and Glonass systems. His research was further supported by several ARC grants. Former graduate students Chalermchon Satirapod (1998-late-2001) and Tajul Musa (mid-2002-2006) have progressed this research. New triple carrier algorithms are currently being researched within the CRC-SI Project 1.04 in collaboration with Yanming Feng (Queensland University of Technology).
- Real-time GPS positioning issues; this research addressed the critical issues of rapid online (real-time) ambiguity resolution and validation for kinematic carrier phase-based GPS/Glonass positioning, i.e." real-time kinematic" or RTK. This research was undertaken for both single baseline mode as well as network mode (the latter necessary for the reference station network processing to support network-RTK), by Shaowei Han and Liwen Dai. Keun Lee developed a number of carrier phase-smoothed filter algorithms. Since 2002, TCP/IP and UDP/IP algorithms for RTCM-RTK message transmission by wireless, packet-based communications systems have been investigated. This research is being continued using the Sydney CORS Network, or "SydNet", principally by Thomas Yan, on topics such as NTRIP, RTCM and other industry protocols and formats for real-time operations. Software development is currently being undertaken to support future research, e.g. by integrating Locata data (see Theme 3).
- Network-RTK is the culmination of several years of research into static and kinematic network-based GPS positioning that led to the establishment of the Singapore Integrated Multiple Reference Station Network (commenced in 1999). This was used as a testbed for new network-RTK algorithms. In 2003 it was proposed to establish a similar CORS network in Sydney. The Sydney Network ("SydNet") functions as an 'open air' laboratory for network-RTK research, including the communications/user aspects, and has been used for CRC-SI and ARC-funded research projects. SNAP Lab is also a participant in the International GNSS Service (IGS) Real-Time Pilot Project.
- Next generation CORS networks is a research field led by Prof. Chris Rizos and Dr. Samsung Lim, currently supported by CRC-SI funding. Research Assistants Yong Heo and Thomas Yan are engaged on this project. Research challenges range from designing the appropriate IT components and GNSS CORS receiver technology, and data processing algorithms utilising the new GNSS signals, new processing methodologies based on different configurations of CORS and user GNSS receivers, and the IGS service, leading to new RTK services.
- OSGRS is an Open Source project ('Open Source GNSS Reference Server') to develop the software and protocols for operating an Assisted-GNSS (A-GNSS) server connected to one or more reference stations. The protocol is known as GRIP (based on XML), and currently the server connects to a NovAtel OEM3 or OEM4 reference receiver. Work is underway to connect via the NTRIP protocol to any CORS receiver that outputs RTCM messages 18 & 19. The OSGRS provides "assistance" messages to user receivers able to make use of such messages to rapidly acquire weak GPS/GNSS signals. These receivers typically are found within mobilephones and similar devices. The software can be downloaded from http://sourceforge.net/projects/osgrs.
A Short History ... The following is a sample of SNAP geodesy, CORS GNSS and high-accuracy GNSS algorithm research carried out over the years, with reference to seminal papers:
- GPS Geodesy in Australia 1984-93: GPS satellite orbit determination
in Australia; potential of GPS for geodynamic studies; Antarctica GPS
surveys; precise regional GPS survey of network of tide gauges in Bass
Strait. Software and algorithms developed within the group led by Assoc.
Prof. Art Stolz (with Chris Rizos
and Ewan Masters as postdoctoral fellows), with national and international
collaborators. Sample papers:
RIZOS, C., STOLZ, A., & MASTERS, E.G., 1984. Surveying and geodesy in Australia with GPS. Aust. Surveyor, 32(2), 202-225.
RIZOS, C., & STOLZ, A., 1985. Force modelling for GPS satellite orbits. 1st Int. Symp. on Precise Positioning with GPS, Rockville, Maryland, 15-19 April, 87-98.
RIZOS, C., GOVIND, R. & STOLZ, A., 1989. The Australian GPS orbit determination pilot project: a status report. IAG symp. 101 "Global and Regional Geodynamics", eds. P. Vyskocil, C. Reigber & P.A. Cross, Edinburgh, U.K., 3-12 August, 164-172.
RIZOS, C., COLEMAN, R., & ANANGA, N., 1991. The Bass Strait GPS survey: preliminary results of an experiment to connect Australian height datums. Aust. J. Geod. Photo. Surv., 55, 1-25.
RIZOS, C., MORGAN, P., & CHU, C.M., 1993. GPS orbit computations in Australia within the International GPS Geodynamics Service: should we? could we? 7th Int. Symp. on Geodesy & Physics of the Earth, Potsdam, Germany, 5-10 October, IAG Symp. No.112, 28-32.
STOLZ, A., MASTERS, E.G., & RIZOS, C., 1984. Determination of GPS satellite orbits for geodesy in Australia. Aust. J. Geod. Photo. Surv., 40, 41-52.
STOLZ, A., RIZOS, C., HIRSCH, B., SCHUTZ, B., & TAPLEY, B., 1987. An experiment to determine regional and global GPS satellite orbits. Aust. J. Geod. Photo. Surv., 46 & 47, 1-16.
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GPS Data Modelling 1984-94: differenced vs undifferenced algorithms; cycle slip detection; parameterisation of "clock biases". A productive period of GPS research by former graduate students Don Grant, Penshan Hung and Cliff Chu, when GPS observation models were still an intense topic of research. Sample papers:
GRANT, D.B., RIZOS, C., & STOLZ, A., 1990. Dealing with GPS biases: some theoretical and software considerations. In "Contributions to GPS studies from the School of Surveying", C. Rizos (ed.), UNISURV Rept. S38, School of Surveying, The University of New South Wales, 204pp.
HUNG, P.S., & RIZOS, C., 1992. Least squares adjustment algorithms for undifferenced GPS data processing. J. Surv.Eng., 34(4), Chinese Soc. of Surv. Eng., 33-46.
RIZOS, C.,& GRANT, D.B., 1990. Time in GPS. In "Contributions to GPS studies from the School of Surveying", C. Rizos (ed.), UNISURV Rept. S38, School of Surveying, The University of New South Wales, 204pp.
RIZOS, C., & CHU, C.M., 1993. Automatic detection and repair of cycle slips on a single station basis. J. Surv.Eng., 35(1), Chinese Soc. of Surv. Eng., 47-64.
- GPS Data Processing Software/Algorithms 1988-94: Kalman filtering
algorithms; UNSW satellite measurement analysis software system (USMASS);
simple baseline estimation software. Following the algorithm development,
several attempts were made to develop a suite of software for precise
estimation of receiver coordinates (as well as other parameters such
as orbit state, clock biases, etc.). Graduate students who made contributions
included Wan Fu, Mustafa Subari (see SUBARI, M.D., 1997, Low-Cost
GPS Systems for Intermediate Surveying and Mapping Accuracy Applications,
UNISURV S-50), S. Subsuantaeng & C. Subarya.
Sample papers:
RIZOS, C., & STOLZ, A., 1988. The UNSW satellite measurement analysis software system (USMASS). Aust. J. Geod. Photo. Surv., 48, 1-28.
RIZOS, C., SUBSUANTAENG, S., & SUBARYA, C., 1990. Developing and testing GPS software: considerations, results and conclusions. 2nd. Int. Symp. on Precise Pos. with GPS, Ottawa, Canada, 3-7 September, 961-976.
RIZOS, C., SUBARI, M., & FU, W.X., 1994. The use of low-cost GPS navigation receivers for surveying applications. Commission 5 "Survey Instruments & Methods", XXth F.I.G. Congress, Melbourne, Australia, 5-12 March, 139-151.
SUBARI, M., & RIZOS, C., 1994. The low-cost GPS surveying package. The Surveyor, Professional Journal of the Institution of Surveyors Malaysia, 29(4), 27-33.
- Planning GPS Surveys 1990-95: development of BDOPs (or "Bias
Dilution of Precision") by former graduate student Bertrand Merminod:
HAN, S. & RIZOS, C., 1995. GPS network design and adjustment for rapid static operational mode. Proc. 5th S.E.Asian and 36th Australian Surveyors Congress, Singapore, 16-20 July.
MERMINOD, B., GRANT, D.B., & RIZOS, C., 1990. Planning GPS surveys - using appropriate precision indicators. Can. Inst. Surv. & Mapping J., 44(3), 233-249.
MERMINOD, B., & RIZOS, C., 1994. Optimisation of rapid static GPS surveys. Manuscripta Geodaetica, 19(4), 231-246.
- GPS Ambiguity Resolution Studies 1995-97: constructing double-differenced
ambiguities; developing and testing ambiguity resolution algorithms;
dual-frequency data techniques; etc. This was an extremely productive period
by Shaowei Han while he was a
graduate student between 1995-97. Readers are referred to his PhD thesis:
HAN, S., 1997, Carrier Phase-Based Long-Range GPS Kinematic Positioning,
UNISURV S-49. Sample papers:
HAN, S., 1997. Ambiguity recovery for GPS long range kinematic positioning. Navigation, Journal of The Institute of Navigation, USA, 44(2), 257-266.
HAN, S., & RIZOS, C., 1995. A new method for constructing multi-satellite ambiguity combinations for improved ambiguity resolution. 8th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'95, Palm Springs, California, 12-15 September, 1145-1153.
HAN, S., & RIZOS, C., 1996. A comparison of GPS ambiguity resolution techniques. Int. Symp. on GPS, Digital Photogrammetry Systems, Remote Sensing & Geographical Systems (Geo-Informatics'96), Wuhan, P.R. China, 16-19 October, Vol.1, 136-146.
HAN, S. & RIZOS, C., 1996. Improving the computational efficiency of the Ambiguity Function algorithm. Journal of Geodesy, 70(6), 330-341.
HAN, S., & RIZOS, C., 1996. Integrated method for instantaneous ambiguity resolution using new generation GPS receivers. IEEE Position Location & Navigation Symp., Atlanta, Georgia, 22-25 April, 254-261.
- Quality Control Research: identification of observation outliers;
ambiguity validation; RAIM; etc. Sample papers:
DAI, L., HAN, S., & RIZOS, C., 1999. A multiple outlier detection algorithm for instantaneous ambiguity resolution for carrier phase-based GNSS positioning. Int. Symp. on Digital Earth (ISDE), Beijing, P.R. China, 29 November - 2 December, 321-332.
HAN, S., 1997. Quality control issues relating to ambiguity resolution for real-time GPS kinematic positioning. Journal of Geodesy, 71(6), 351-361.
HAN, S. & RIZOS, C., 1996. Validation and rejection criteria for integer least-squares estimation. Survey Review, 33(260), 375-382.
HAN, S., & RIZOS, C., 1998. Quality control, ambiguity resolution and GPS network adjustment. Proc. 11th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'98, Nashville, Tennessee, 15-18 September, 39-48.
HEWITSON, S., & WANG, J., 2006. GNSS Receiver Autonomous Integrity Monitoring (RAIM) performance analysis. GPS Solutions, 10(3), 155-170. (Download PDF)
HEWITSON, S., & WANG, J., 2007. GNSS Receiver Autonomous Integrity Monitoring (RAIM) with a dynamic model. Journal of Navigation, Royal Institute of Navigation, 60(2), 247-263. (Download PDF)
HEWITSON, S., LEE, H.K., & WANG, J., 2004. Localizability analysis for GPS/Galileo Receiver Autonomous Integrity Monitoring. The Journal of Navigation, 57, 249-259. (Download PDF)
JIA, M., RIZOS, C. & DING, X., 1996. A new reliability measure for dynamic survey systems and its application in dynamic system quality control. Proc. 9th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'96, Kansas City, Missouri, 17-20 September, 1215-1223.
MERTIKAS, S.P. & RIZOS, C., 1997. On-line detection of abrupt changes in the carrier phase measurement of GPS. Journal of Geodesy, 71, 469-482.
MERTIKAS, S.P., & RIZOS, C., 1998. Real-time failure detection in the carrier phase measurements of GPS by robust and conventional Kalman filtering. Journal of Marine Geodesy, 21(1), 41-65.
WANG, J., & WANG, J., 2007. Mitigating the effect of multiple outliers on GNSS navigation with M-estimation schemes. IGNSS2007 Symp. on GPS/GNSS, Sydney, Australia, 4-6 December, paper 70, CD-ROM procs. (Download PDF)
WANG, J., WANG, J., & ROBERTS, C.A., 2007. Reducing carrier phase errors with EMD-Wavelet for precise GPS positioning. U.S. Institute of Navigation National Tech. Meeting, San Diego, California, 22-24 January, 919-928. (Download PDF)
- Optimal Adjustment of Baselines: improved network adjustment
of GPS baselines. Sample papers:
HAN, S. & RIZOS, C., 1995. Standardization of the variance-covariance matrix for GPS rapid static positioning. Geomatics Research Australasia, 62, 37-54.
HAN, S. & RIZOS, C., 1995. Selection and scaling of simultaneous baselines for GPS network adjustment, or correct procedures for processing trivial baselines. Geomatics Research Australasia, 63, 51-66.
HAN, S., & RIZOS, C., 1998. Quality control, ambiguity resolution and GPS network adjustment. Proc. 11th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'98, Nashville, Tennessee, 15-18 September, 39-48.
HAN, S., & RIZOS, C., 1999. Network adjustment issues using mixed GPS surveying techniques. 40th Aust. & 6th S.E.Asian Surveyors Congress, Fremantle, Australia, 30 October - 5 November, 68-76. (Download PDF)
JANSSEN, V., 2001. Optimising the number of double-differenced observations for GPS networks in support of deformation monitoring applications. GPS Solutions, 4(3), 41-46. (Download PDF)
- Long-Range GPS Kinematic Positioning 1995: pioneering work
with Dr. Oscar Colombo and the late Bernie Hirsch (research assistant
in SNAP) in Sydney Harbour experiments, that demonstrated the capability
of what we called "kinematic geodesy" at the time, based on
estimating in a complex Kalman filter the simultaneous estimation of
mobile receiver coordinates and GPS satellite parameters using data from a network
of CORS GPS reference stations:
COLOMBO, O.L., RIZOS, C., & HIRSCH, B., 1995. Decimeter-level DGPS navigation over distances of more than 1000km: results of the Sydney Harbour experiment. 1995 Mobile Mapping Symp., Columbus, Ohio, 24-26 May, 105-114.
COLOMBO, O.L., RIZOS, C., & HIRSCH, B., 1995. Long-range carrier phase DGPS: the Sydney Harbour experiment. 4th Int. Conf. Differential Satellite Navigation Systems DSNS95, Bergen, Norway, 24-28 April, paper no.61, 8pp. COLOMBO, O.L., & RIZOS, C., 1995. Testing high accuracy long range carrier phase DGPS in Australasia. IAG Symp. 115, "GPS Trends in Precise Terrestrial, Airborne, and Spaceborne Applications", Boulder, Colorado, 2-14 July, 226-230.
- Medium & Long-Range GPS Positioning 1995-98: groundbreaking
work by Shaowei Han during his
PhD studies (see Carrier Phase-Based Long-Range GPS Kinematic Positioning,
UNISURV S-49) and subsequently, including ambiguity
resolution and ambiguity-recovery using dual-frequency carrier phase
and pseudo-range data, and long-range airborne kinematic positioning experiment
in support of Laser Airborne Depth Sounder (LADS). Sample papers:
CHEN, H.Y., 2000. An instantaneous ambiguity resolution procedure suitable for medium-scale GPS reference station networks. 13th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Salt Lake City, Utah, 19-22 September, 1061-1070. (Download PDF)
CHEN, H.Y., DAI, L., RIZOS, C., & HAN, S., 2005. Ambiguity recovery using the triple-differenced carrier phase type approach for long-range GPS kinematic positioning. Marine Geodesy, 28(2), 119-135. (Download PDF)
FENG, Y. & HAN, S., 1996. A long-range dynamic GPS system and positioning results. Proc. IEEE Position Location & Navigation Symp., Atlanta, Georgia, 22-25 April, 711-718.
FENG, Y., KUBIK, K. & HAN, S., 1996. A long-range dynamic GPS positioning system and its test results. Proc. XVIIIth ISPRS Congress, Vienna, Austria, 9-19 July.
HAN, S., & RIZOS, C., 1995. On-the-fly ambiguity resolution for long range GPS kinematic positioning. IAG Symp. 115, "GPS Trends in Precise Terrestrial, Airborne, & Spaceborne Applications", Boulder, Colorado, 2-14 July, 290-294.
HAN, S. & RIZOS, C., 1996. Centimeter GPS kinematic or rapid static surveys without ambiguity resolution. Journal of Surveying & Land Information Systems, 56(3), 143-148.
HAN, S., & RIZOS, C., 1997. An instantaneous ambiguity resolution technique for medium-range GPS kinematic positioning. 10th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'97, Kansas City, Missouri, 16-19 September, 1789-1800.
HAN, S., RIZOS, C., & ABBOT, R., 1998. Long-range GPS kinematic positioning and its application in sea surface determination. Spatial Information Science & Technology (SIST'98), Wuhan Technical University of Surveying & Mapping, Wuhan, P.R. China, 13-16 December, 46-54.
HAN, S., RIZOS, C., & ABBOT, R., 1998. Flight testing and data analysis of airborne GPS LADS survey. 11th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'98, Nashville, Tennessee, 15-18 September, 1211-1221.
ISSHIKI, H., & WANG, J., 2006. A new algorithm for long baseline kinematic positioning with dual-frequency GPS/GNSS receivers. Artificial Satellites, 41(4), 117-135. (Download PDF)
- Ionospheric Parameters from GPS Measurements: undertaken by
former graduate student David Lin during his studies, and continued
in 2005 under ARC funding:
FU, W.X., HAN, S., RIZOS, C., KNIGHT, M., & FINN, A., 1999. Real-time ionospheric scintillation monitoring using GPS. 12th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'99, Nashville, Tennessee, 14-17 September, 1461-1471. (Download PDF)
JIN, S.G., WANG, J., ZHANG, H., & ZHU, W., 2004. Real-time monitoring and prediction of ionospheric electron content by means of GPS. Chinese Astronomy & Astrophysics, 28, 331-337. (Download PDF)
JIN, S.G., PARK, J.U., WANG, J., CHOI, B.K., & PARK, P.H., 2006. Electron density profiles derived from ground-based GPS observations. The Journal of Navigation, 59(3), 395-401. (Download PDF)
LIN, L.S., 1997. A novel approach to improving the accuracy of real-time ionospheric delay estimation using GPS. Proc. 10th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'97, Kansas City, Missouri, 16-19 September, 169-178.
LIN, L.S., & RIZOS, C.,1996. An algorithm to estimate GPS satellite and receiver L1/L2 differential delay biases and its application to regional ionosphere modelling. Geomatics Research Australasia, 65, 1-26.
LIN, L.S., & RIZOS, C., 1997. On real-time regional ionosphere modelling using grid-based algorithms. 3rd Satellite Navigation Technology Conf., Sydney, Australia, 8-10 April, paper 41.
LIN, L.S. & RIZOS, C., 1997. On real-time regional ionosphere modelling using grid-based algorithms. Proc. 3rd Satellite Navigation Technology Conf., Sydney, Australia, 8-10 April, paper no. 41.
LIN, L.S., RIZOS, C., & MERTIKAS, S.P., 1998. Real-time failure detection and repair in ionospheric delay estimation using GPS by robust and conventional Kalman filter state estimates. In "Advances in Positioning and Reference Frames", Springer-Verlag, ISBN 3-540-64604-3, 295-300.
OUYANG, G., WANG, J., WANG, J., & COLE, D., 2007. Generating a 3D TEC model for Australia with combined LEO satellite and ground based GPS data sets. 20th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Fort Worth, Texas, 25-28 September, 2285-2290. (Download PDF)
ZHANG, H., WANG, J., ZHU, W.Y., & HUANG, C., 2005. Gaussian random process and its application for detecting the ionospheric disturbances using GPS. Journal of GPS, 4(1-2), 76-81. (Download PDF)
- Tropospheric Delay Studies: primarily for improved baseline
estimation, but also to improve InSAR and pseudolite results:
GE, L., CHANG, H.C., YONEZAWA, C., & RIZOS, C., 2004. GPS derived tropospheric delay corrections to radar interferometry. 17th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Long Beach, California, 21-24 September, 881-891. (Download PDF)
JANSSEN, V., 2003. GPS-derived tropospheric delay corrections to Differential InSAR results. 16th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Portland, Oregan, 9-12 September, 2692-2704. (Download PDF) JANSSEN, V., GE, L., & RIZOS, C., 2004. Tropospheric corrections to SAR interferometry from GPS observations. GPS Solutions, 8(3), 140-151. (Download PDF)
MUSA, T.A., LIM, S., & RIZOS, C., 2005. Low latitude troposphere: A preliminary study using GPS CORS data in South East Asia. U.S. Institute of Navigation National Tech. Meeting, San Diego, California, 24-26 January, 685-693. (Download PDF)
ROBERTS, C., & RIZOS, C., 2001. Mitigating differential troposphere for GPS-based volcano monitoring. 5th Int. Symp. on Satellite Navigation Technology & Applications, Canberra, Australia, 24-27 July, paper 38, CD-ROM proc.(Download PDF)
TSUJII, T., WANG, J., RIZOS, C., HARIGAE, M., & INAGAKI, T., 2001. Tropospheric delay mitigation for high-altitude vehicle positioning. Geomatics Research Australasia, 75, 87-106. (Download PDF)
WANG, J.J., WANG, J., SINCLAIR, D., WATTS, L., & LEE, H.K., 2005. Tropospheric delay estimation for pseudolite positioning. Journal of GPS, 4(1-2), 106-112. (Download PDF)
XU, C., WANG, H., GE, L., YONEZAWA, C., & CHENG, P., 2006. InSAR tropospheric delay mitigation by GPS observations: A case study in Tokyo area. Journal of Atmospheric & Solar Terrestrial Physics, 68, 629Ð638. (Download PDF)
- Combined GPS & Glonass Algorithms: modelling and ambiguity
resolution; single-baseline and network-based techniques. Contributions
by Shaowei Han, Liwen
Dai (see DAI, L., 2002, Augmentation of GPS with Glonass and
Pseudolite Signals for Carrier Phase-Based Kinematic Positioning,
UNISURV S-72) and Jinling
Wang:
DAI, L., 2000. Dual-frequency GPS/GLONASS real-time ambiguity resolution for medium-range kinematic positioning. 13th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Salt Lake City, Utah, 19-22 September, 1071-1080. (Download PDF)
DAI, L., WANG, J., RIZOS, C., & HAN, S., 2001. Real-time carrier phase ambiguity resolution for GPS/GLONASS reference station networks. Int. Symp. on Kinematic Systems in Geodesy, Geomatics & Navigation (KIS2001), Banff, Canada, 5-8 June, 475-481. (Download PDF)
DAI, L., HAN, S., & RIZOS, C., 2001. Performance analysis of integrated GPS/GLONASS carrier phase-based positioning. Journal of Geospatial Information Science, 4(4), 9-18. (Download PDF)
DAI, L., RIZOS, C., & HAN, S., 2003. An adaptive procedure for carrier phase-based GPS/GLONASS positioning. Geomatics Research Australasia, 78, 19-36. (Download PDF)
DAI, L., WANG, J., RIZOS, C., & HAN, S., 2003. Predicting atmospheric biases for real-time ambiguity resolution in GPS/GLONASS reference station networks. Journal of Geodesy, 76, 617-628. (Download PDF)
HAN, S., DAI, L., & RIZOS, C., 1999. A new data processing strategy for combined GPS/Glonass carrier phase-based positioning. 12th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'99, Nashville, Tennessee, 14-17 September, 1619-1627. (Download PDF)
WANG, J., 2000. An approach to GLONASS ambiguity resolution. Journal of Geodesy, 74(5), 421-430.
WANG, J., RIZOS, C., STEWART, M.P., & LEICK, A., 2001. GPS and GLONASS integration: Modelling and ambiguity resolution issues. GPS Solutions, 5(1), 55-64. (Download PDF)
WANG, J., STEWART, M.P., & TSAKIRI, M., 2001. Modelling GLONASS measurements for precise positioning. Survey Review, 36(282), 110-120.
- Multi-Frequency GPS/GNSS Algorithms: for fast ambiguity resolution
using the "modernized" GPS L1, L2 and L5 signals, Galileo and other GNSS:
FENG, Y., & RIZOS, C., 2005. Three carrier approaches for future global, regional and local GNSS positioning services: Concepts and performance perspectives. 18th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Long Beach, California, 13-16 September, 2277-2287. (Download PDF)
FENG, Y., & WANG, J., 2007. Exploiting GNSS RTK performance potentials with GPS & virtual Galileo measurements. U.S. Institute of Navigation National Tech. Meeting, San Diego, California, 22-24 January, 218-226. (Download PDF)
FENG, Y., RIZOS, C., & MOODY, M., 2006. Exploring GNSS performance benefits from multiple satellite systems and multiple carrier signals using existing GPS constellation and measurements. Symp. on GPS/GNSS (IGNSS2006), Surfers Paradise, Australia, 17-21 July, CD-ROM procs. (Download PDF)
FENG, Y., RIZOS, C., & HIGGINS, M., 2007. Multiple carrier ambiguity resolution methods and performance benefits for regional RTK and PPP GNSS positioning services. 20th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Fort Worth, Texas, 25-28 September, 668-678. (Download PDF)
HAN, S., & RIZOS, C., 1999. The impact of two additional civilian GPS frequencies on ambiguity resolution strategies. 55th National Meeting U.S. Institute of Navigation, "Navigational Technology for the 21st Century", Cambridge, Massachusetts, 28-30 June, 315-321. (Download PDF)
- GPS Attitude Determination: multi-antenna algorithms, with
or without gyro aiding. Contributions by Shaowei
Han, Michael Moore, and
Yong Li. Sample papers:
HAN, S., WONG, K. & RIZOS, C., 1997. Instantaneous ambiguity resolution for real-time GPS attitude determination. Proc. Int. Symp. on Kinematic Systems in Geodesy, Geomatics & Surveying (KIS'97), Banff, Canada, 3-6 June, 409-416.
HAN, S., & RIZOS, C., 1999. Single epoch ambiguity resolution for real-time GPS attitude determination with the aid of one dimensional optical fibre gyro. GPS Solutions, 3(1), 5-12.
HWANG, D.H., OH, S.H., LEE, S.J., PARK, C., & RIZOS, C., 2005. Design of a low-cost attitude determination GPS/INS integrated navigation system for a UAV. GPS Solutions, 9(4), 294-311. (Download PDF)
LI, Y., & YUAN, J., 2005. Attitude determination using GPS vector observations. GNSS World of China, 30(3), 51-56, ISSN 1008-9268. (Download PDF)
LI, Y., DEMPSTER, A.G., & LI, B., 2005. A low-cost attitude heading reference system by combination of GPS and magnetometers and MEMS inertial sensors for mobile applications. Int. Symp. on GPS/GNSS, Hong Kong, 8-10 December, paper 5A-01, CD-ROM procs. (Download PDF)
MOORE, M., 2002. The use of wavelets for determining wing flexure in airborne GPS multi-antenna attitude determination systems. 15th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Portland, Oregan, 24-27 September, 1022-1029. (Download PDF)
MOORE, M., RIZOS, C., & WANG, J., 2002. Quality control issues relating to an attitude determination system using a multi-antenna GPS array. Geomatics Research Australasia, 77, 27-48. (Download PDF)
MOORE, M., RIZOS, C., WANG, J., BOYD, G., & MATTHEW, K., 2003. A GPS based attitude determination system for a UAV aided by low grade angular rate gyros. 16th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Portland, Oregan, 9-12 September, 2417-2424. (Download PDF)
WANG, J., TSUJII, T., RIZOS, C., DAI, L., & MOORE, M., 2000. Integrating GPS and pseudolite signals for position and attitude determination: Theoretical analysis and experiment results. 13th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Salt Lake City, Utah, 19-22 September, 2252-2262. (Download PDF)
- Network-RTK:
multi-reference station techniques were first implemented in real-time,
to complement standard single-baseline RTK ("real-time kinematic")
techniques in the late 1990s by Trimble in their VRS ("virtual
reference station") product. Several university groups have also
carried out fundamental research into VRS-type systems. SNAP assisted
in the establishment of the Singapore Integrated Multiple Reference
Station Network (SIMRSN) and more recently
the SydNet CORS
network. Sample papers:
CHEN, X., HAN, S., RIZOS, C., & GOH, P.C., 2000. Improving real-time positioning efficiency using the Singapore Integrated Multiple Reference Station Network (SIMRSN). 13th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Salt Lake City, Utah, 19-22 September, 9-18. (Download PDF)
RIZOS, C., 2002. Network RTK research and implementation: A geodetic perspective. Journal of Global Positioning Systems, 1(2), 144-150. (Download PDF)
RIZOS, C., & HAN, S., 2003. Reference station network based RTK systems - Concepts & progress. Wuhan University Journal of Nature Sciences, 8(2B), 566-574. (Download PDF)
RIZOS, C., SATIRAPOD, C., CHEN, H.Y., & HAN, S., 1999. GPS with multiple reference stations: surveying scenarios in metropolitan areas. 40th Aust. & 6th S.E.Asian Surveyors Congress, Fremantle, Australia, 30 October - 5 November, 37-49. (Download PDF)
RIZOS, C., HAN, S., CHEN, H.Y., & GOH, P.C., 1999. Continuously operating GPS reference station networks: new algorithms and applications of carrier phase-based, medium-range, static and kinematic positioning. In "Quo vadis geodesiaŠ?", special publication to celebrate Prof. Erik W. Grafarend's 60th birthday, Dept. of Geodesy & Geoinformatics, University of Stuttgart, ISSN 0933-2839, 367-378.
RIZOS, C., HAN, S., & CHEN, H.Y., 2000. Regional-scale multiple reference stations for real-time carrier phase-based GPS positioning: a correction generation algorithm. Earth, Planets & Space, 52(10), 795-800. (Download PDF)
RIZOS, C., KINLYSIDE, D., YAN, T., OMAR, S., & MUSA, T.A., 2003. Implementing network RTK: The SydNET CORS infrastructure. 6th Int. Symp. on Satellite Navigation Technology Including Mobile Positioning & Location Services, Melbourne, Australia, 22-25 July, CD-ROM proc., paper 50. (Download PDF)
ROBERTS, C.A., YAN, T., ALLISON, S., HENDRO, F., KINLYSIDE, D., McELROY, S., & JONES, G., 2007. Centimetres across Sydney: First results from the SydNet CORS network. Spatial Sciences Conference, Hobart, Australia, 14-18 May, 152-161. (Download PDF)
YAN, T.S., 2006. GNSS data protocols: Choice and implementation. Symp. on GPS/GNSS (IGNSS2006), Surfers Paradise, Australia, 17-21 July, CD-ROM procs. (Download PDF)
YAN, T., 2007. Test results from the next generation of NTRIP. IGNSS2007 Symp. on GPS/GNSS, Sydney, Australia, 4-6 December, paper 85, CD-ROM procs. (Download PDF)
ZHANG, K., RIZOS, C., ROBERTS, C.A., KEALY, A., GE, L., WU, F., RAMM, P., HALE, M., KINLYSIDE, D., & HARCOMBE, P., 2006. Sparse or dense: Challenges of Australian network RTK. Symp. on GPS/GNSS (IGNSS2006), Surfers Paradise, Australia, 17-21 July, CD-ROM procs. (Download PDF)
- Stochastic Modelling: while an enormous topic, SNAP researchers
have focussed on modelling of temporal and physical correlations, adaptive
stochastic modelling for AR, etc., for network-based GPS positioning,
as well as other positioning sensors. Contributions by Jinling
Wang, Shaowei Han and former
graduate student Chalmerchon Satirapod
(SATIRAPOD, C., 2002, Improving the GPS Data Processing Algorithm
for Precise Static Relative Positioning, UNISURV
S-68). Sample papers:
DAI, L., RIZOS, C., & HAN, S., 2003. An adaptive procedure for carrier phase-based GPS/GLONASS positioning. Geomatics Research Australasia, 78, 19-36. (Download PDF)
DING, W., WANG, J., & RIZOS, C., 2006. Stochastic modelling strategies in GPS/INS data fusion process. Symp. on GPS/GNSS (IGNSS2006), Surfers Paradise, Australia, 17-21 July, CD-ROM procs. (Download PDF)
DING, W., WANG, J., & RIZOS, C., 2006. Improving covariance based adaptive estimation for GPS/INS integration. 12th IAIN Congress & 2006 Int. Symp. on GPS/GNSS, Jeju, Korea, 18-20 October, 259-264. (Download PDF)
HAN, S., & RIZOS, C., 1997. An instantaneous ambiguity resolution technique for medium-range GPS kinematic positioning. 10th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation GPS ION'97, Kansas City, Missouri, 16-19 September, 1789-1800.
JIN, S., & WANG, J., 2004. Impacts of stochastic models on near real-time GPS ZTD estimations. 17th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Long Beach, California, 21-24 September, 941-946. (Download PDF)
JIN, S.G., WANG, J., & PARK, P.H., 2005. An improvement of GPS height estimations: stochastic modeling. Earth Planets Space, 57(4), 253-259. (Download PDF)
MUSA, T.A., WANG, J., & RIZOS, C., 2003. Stochastic modelling for network-based GPS positioning. 6th Int. Symp. on Satellite Navigation Technology Including Mobile Positioning & Location Services, Melbourne, Australia, 22-25 July, CD-ROM proc., paper 41. (Download PDF)
MUSA, T.A., WANG, J., & RIZOS, C., 2004. A stochastic modelling method for network-based GPS positioning. GNSS2004, Rotterdam, The Netherlands, 16-19 May, CD-ROM proc., paper 143. (Download PDF) SATIRAPOD, C., WANG, J., & RIZOS, C., 2001. A new stochastic modelling procedure for precise static GPS positioning. Zeitschrift für Vermessungswessen, 126(6), 365-373. (Download PDF)
SATIRAPOD, C., WANG, J., & RIZOS, C., 2001. Modelling residual systematic errors in GPS positioning: Methodologies and comparative studies. IAG Scientific Assembly, Budapest, Hungary, 2-7 September, CD-ROM proc. Symp. C5 "Biases in GNSS Positioning", poster 14. (Download PDF)
SATIRAPOD, C., WANG, J., & RIZOS, C., 2002. A simplified MINQUE procedure for the estimation of variance-covariance components of GPS observables. Survey Review, 36(286), 582-590. (Download PDF)
WANG, J., 2000. Stochastic modeling for real-time kinematic GPS/Glonass positioning. Navigation, 46(4), 297-305.
WANG, J., SATIRAPOD, C., & RIZOS, C., 2002. Stochastic assessment of GPS carrier phase measurements for precise static relative positioning. Journal of Geodesy, 76(2), 95-104. (Download PDF)
WANG, J., LEE, H.K., LEE, Y.J., MUSA, T.A., & RIZOS, C., 2005. Online stochastic modelling for network-based GPS real-time kinematic positioning. Journal of GPS, 4(1-2), 113-119. (Download PDF)
- Multipath Studies: these commenced in 1997, and have been contributed
to by Shaowei Han, David Lin,
Linlin Ge and Chalmerchon
Satirapod:
FANTINO, M., DOVIS, F., & WANG, J., 2005. Quality monitoring for multipath affected GPS signals. Journal of GPS, 4(1-2), 151-159. (Download PDF)
GE, L., HAN, S., & RIZOS, C., 2000. Multipath mitigation using an adaptive filter. GPS Solutions, 4(2), 19-30. (Download PDF)
GE, L., & RIZOS, C., 2001. Slope stability monitoring by the use of GPS multipath as a signal. IAG Scientific Assembly, Budapest, Hungary, 2-7 September, CD-ROM proc. Symp. C3 "New Concepts in Engineering Geodesy", poster 1. (Download PDF)
GE, L., HAN, S., & RIZOS, C., 2002. GPS multipath change detection at permanent GPS stations. Survey Review, 36(283), 306-322. (Download PDF)
HAN, S., & RIZOS, C., 1997. Multipath effects on GPS in mine environments. Xth Int. Congress of the Int. Soc. for Mine Surveying, Fremantle, Australia, 2-6 November, 447-457.
HAN, S., & RIZOS, C., 2000. GPS multipath mitigation using FIR filters. Survey Review, 35(277), 487-498.
LIN, L.S., & RIZOS, C., 1997. Use of multipath template technique for mitigating GPS pseudo-range multipath: methodology and test results. First Trans Tasman Surveyors Conf., Newcastle, Australia, 12-18 April, paper 22.
SATIRAPOD, C., & RIZOS, C., 2005. Multipath mitigation by wavelet analysis for GPS base station applications. Survey Review, 38(295), 2-10. (Download PDF)
SATIRAPOD, C., KHOONPHOOL, R., & RIZOS, C., 2003. Multipath mitigation of permanent GPS stations using wavelets. 2003 Int. Symp. on GPS/GNSS, Tokyo, Japan, 15-18 November, 133-139. (Download PDF)
WEISS, J.P., AXELRAD, P., DEMPSTER, A.G., RIZOS, C., & LIM, S., 2007. Estimation of simplified reflection coefficients for improved modeling of urban multipath. 63rd U.S. Institute of Navigation Annual Meeting, Cambridge, Mass., 23-25 April, 635-643. (Download PDF)
- Dynamic Modelling & Kinematic Positioning Algorithms: Kalman
filters and phase-smoothed filters for kinematic GPS positioning &
attitude determination, and integrity monitoring, using carrier phase
and pseudo-range data. Contributed to by former visiting fellow Dr. H.K.
Lee and several former graduate students:
DAI, L., RIZOS, C., & HAN, S., 2003. An adaptive procedure for carrier phase-based GPS/GLONASS positioning. Geomatics Research Australasia, 78, 19-36. (Download PDF) HAN, S., & RIZOS, C., 2000. An instantaneous ambiguity resolution technique for medium-range GPS kinematic positioning. Navigation, 47(1), 17-32.
LEE, H.K., & RIZOS, C., 2003. A new recursive carrier-smoother-code filter for differential Global Navigation Satellite Systems. 11th Int. Assoc. of Institutes of Navigation World Congress, Berlin, Germany, 21-24 October, CD-ROM proc., paper 263. (Download PDF) LEE, H.K., RIZOS, C., & JEE, I.G., 2003. Design and analysis of DGPS filters with consistent error covariance information. 6th Int. Symp. on Satellite Navigation Technology Including Mobile Positioning & Location Services, Melbourne, Australia, 22-25 July, CD-ROM proc., paper 47. (Download PDF)
LEE, H.K., RIZOS, C., & JEE, I.G., 2004. Design of kinematic DGPS filters with consistent covariance information. IEE proc. of Radar, Sonar & Navigation, 151(6), 382-388. (Download PDF)
LEE, H.K., WANG, J., & RIZOS, C., 2005. An integer ambiguity resolution procedure for GPS/Pseudolite/INS integration. Journal of Geodesy, 79, 242-255. (Download PDF)
LI, Y., ZHANG, K., & GRENFELL, R., 2005. Improved Knight method based on narrowed search space for instantaneous attitude determination. The Journal of Navigation, 52(2), 111-119. (Download PDF)
LIM, S., & TRAN, B.Q., 2004. Convergence of Block Decorrelation Method for the integer ambiguity fix. Journal of GPS, 3(1-2), 290-295. (Download PDF)
MOORE, M., & WANG, J., 2001. Adaptive dynamic modelling for kinematic positioning. IAG Scientific Assembly, Budapest, Hungary, 2-7 September, CD-ROM proc. Symp. C4 "Probabilistic and Non-Probabilistic Assessment in Data Analysis", paper 4. (Download PDF)
MOORE, M., & WANG, J., 2003. An extended dynamic model for kinematic positioning. Journal of Navigation, 56, 79-88. (Download PDF)
WANG, Z., RIZOS, C., & LIM, S., 2006. Single epoch algorithm based on Tikhonov regularization for deformation monitoring using single frequency GPS receivers. Survey Review, 38(302), 682-688. (Download PDF)
- Ground-based
Regional Augmentation System (GRAS) Studies were conducted by
Bill Ely, a graduate student
from the GNSS Program Office, AirServices Australia, who completed his
PhD studies in 2006 (see ELY, W.S., 2006. GRAS
development, approval and implementation in Australia. PhD thesis,
School of Surveying & Spatial Information Systems, University of New
South Wales, Sydney, Australia.
(Digital Thesis here...) . Some of the GRAS papers include:
ELY, W.S., 2001. A portable GNSS data tramsitter: Development and testing. 5th Int. Symp. on Satellite Navigation Technology & Applications, Canberra, Australia, 24-27 July, paper 12, CD-ROM proc.
ELY, W.S., 2003. Development of GRAS cockpit displays for advanced approach and landing procedures. National Technical Meeting of the U.S. Institute of Navigation, Anaheim, California, 22-24 January, 287-299.
ELY, W.S., 2004. Development and flight testing of a low cost VHF data link antenna for the Ground-based Regional Augmentation System. U.S. ION National Technical Meeting, San Diego, California, 26-28 January. (Download PDF)
ELY, W.S., 2004. Use of post-processed GPS data as a truth source for long baseline flight testing of the Ground-based Regional Augmentation System (GRAS). 17th Int. Tech. Meeting of the Satellite Division of the U.S. Institute of Navigation, Long Beach, California, 21-24 September, 325-334. (Download PDF)
ELY, W.S., McPHERSON, K.W., CROSBY, G.K., & STEWART, J.M., 2002. Flight testing of the D8PSK/TDMA datalink technology for the Ground-based Regional Augmentation System. 15th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Portland, Oregan, 24-27 September, 1038-1043. (Download PDF)
- Studies into New CORS Operations & Services, including the impact of improvements in the International GNSS Service (IGS); new business models for CORS networks; server-based positioning architectures; A-GNSS server development; and developments with respect to Galileo and modernized GPS:
DOW, J., NEILAN, R., & RIZOS. C., 2007. The International GNSS Service (IGS): Preparations for the coming decade. 20th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Fort Worth, Texas, 25-28 September, 2136-2144. (Download PDF)
FENG, Y., RIZOS, C., & HIGGINS, M., 2007. Impact of multiple frequency GNSS signals on future regional GNSS services. IGNSS2007 Symp. on GPS/GNSS, Sydney, Australia, 4-6 December, paper 128, CD-ROM procs. (Download PDF)
LIM, S., & RIZOS, C., 2007. A new framework for server-based and thin-client GNSS operations for high accuracy applications in surveying and navigation. 20th Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, Fort Worth, Texas, 25-28 September, 2169-2177. (Download PDF)
RIZOS, C., 2000. GPS survey technology: Why doesn't every Surveyor own a kit? Surveying World, 8(4), 26-29.
RIZOS, C., 2003. GNSS interoperability: Future or fantasy? GPS World Showcase Directions 2004, 14(12), 24-25. (Download PDF)
RIZOS, C., 2005. Trends in geopositioning for LBS, navigation and mapping. Int. Symp. & Exhibition on Geoinformation 2005, Penang, Malaysia, 27-29 September, invited paper. (Download PDF
RIZOS, C., 2006. New GNSS developments and their impact on the geospatial industry. GIS Development Asia-Pacific, 10(6), 34-36. (Download PDF)
RIZOS, C., 2007. Alternatives to current GPS-RTK services & some implications for CORS infrastructure and operations. GPS Solutions, 11(3), 151-158. (Download PDF)
RIZOS, C., & CRANENBROECK, J.van, 2006. Making GNSS-RTK services pay. FIG Congress, Munich, Germany, 8-13 October, CD-ROM procs, paper TS13.1. (Download PDF)
RIZOS, C., HIGGINS, M., & HEWITSON, S., 2005. New GNSS developments and their impact on survey service providers and users. Spatial Sciences Conference, Melbourne, Australia, 12-16 September, 1100-1113, CD-ROM procs. (Download PDF)
YAN, T., MUMFORD, P., DEMPSTER, A.G., RIZOS, C., HOANG, N., & FERNANDO, M., 2007. 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, 2224-2229. (Download PDF)
- Real-time GPS positioning issues; this research addressed the critical issues of rapid online (real-time) ambiguity resolution and validation for kinematic carrier phase-based GPS/Glonass positioning, i.e." real-time kinematic" or RTK. This research was undertaken for both single baseline mode as well as network mode (the latter necessary for the reference station network processing to support network-RTK), by Shaowei Han and Liwen Dai. Keun Lee developed a number of carrier phase-smoothed filter algorithms. Since 2002, TCP/IP and UDP/IP algorithms for RTCM-RTK message transmission by wireless, packet-based communications systems have been investigated. This research is being continued using the Sydney CORS Network, or "SydNet", principally by Thomas Yan, on topics such as NTRIP, RTCM and other industry protocols and formats for real-time operations. Software development is currently being undertaken to support future research, e.g. by integrating Locata data (see Theme 3).
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