Systems for data processing, anaylsis and representation

Allam, Mosaad; Plunkett, Gordon

Bibliographic data

Monograph

Persistent identifier:: 1067490280

Title:: Systems for data processing, anaylsis and representation

Sub title:: ISPRS Commission II Symposium : June 6 - 10, Ottawa, Canada

Scope:: 1 Online-Ressource (XX, 530 Seiten)

Year of publication:: 1994

Place of publication:: Ottawa

Publisher of the original:: The Surveys, Mapping and Remote Sensing, Natural Resources Canada

Identifier (digital):: 1067490280

Illustration:: Illustrationen

Signature of the source:: ZS 312(30,2)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Allam, Mosaad; Plunkett, Gordon

Corporations:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Adapter:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Founder of work:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Other corporate:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Wednesday, June 8, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Joint ISPRS/ GIS '94 Plenary III]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: THE USE OF GPS FOR GIS GEOREFERENCING: STATUS AND APPLICATIONS M. Elizabeth Cannon

Document type:: Monograph

Structure type:: Chapter

hniques res ing Iccuracy 1 (30-60 min) ing ub-metre n (5-15 min) receivers s < 15 km ing vel 4 SVs s < 15 km d processing several m in real-time ng equired al cm level s < 50 km 4 SVs ng 1 required al cm level | s « 50 km | less units is usually quirements, sults during cial. Of the e kinematic > easiest to 0 the use of plifies the s as data itor receiver 0 bps using format, i.e. me mode of achieved in reaks in the t Guard has correction adiobeacons 't of the US dco. Future plans are to expand the service to the entire US coastline (Alsip,1993). The Canadian Coast Guard is also in the process of deploying a similar service in Canada. To achieve cm-level accuracies in real-time, the requirements for data transmission may exceed 2000 bps since the raw carrier phase data must be transmitted. As with post-mission processing, the algorithms are more complex than for code differential processing and thus the development of real-time, cm-level accuracy systems has lagged code differential systems. However, recently systems have been developed which show the feasibility of using real-time kinematic systems for high precision surveys (e.g. Frodge et al., 1994). 4. LAND-BASED APPLICATIONS 41 Sub-Metre Positioning in Static Mode Many GIS applications traditionally required a few metre accuracy for georeferencing static points occupied during a survey. The current emphasis is on sub-metre accuracy which can place particular constraints on the type of GPS receiver technology that must be used as well on the time required to occupy a point. Generally, the GIS community uses standard C/A code technology which delivers 1-3 m accuracy. In order to improve the accuracy below a metre with these receivers, the carrier phase observable must be used and the point occupied for a longer period of time in order to acquire sufficient satellite geometry. A study to determine the time required to reach the sub-metre level, a test was conducted with the Motorola LGT10007M, a GPS/GIS terminal which can track six satellites simultaneously and can also output the carrier phase measurement. Data was collected on baselines of 500 m and 10 km. About 2 hours of data were recorded for each baseline, and post-processed using The University of Calgary's SEMIKIN™ program (Cannon,1990). The data was processed in subsets and the resulting coordinates were compared to the known baseline coordinates in order to determine the achievable accuracy. Figure 3 shows the relationship between site occupation time and 3-D accuracy for the 100 m baseline. Figure 4 shows the same for the 10 km baseline. The two figures clearly show that the achievable accuracy improves as a function of the site Occupation time. Although the results are slightly different for the two baselines due to the increased errors on the 10 km line, they both show that within 5 minutes of data acquisition, the sub-metre level can be met. See Cannon et al. (1993) for further details on the above test. 70 3-D Error (cm) es) S À 0 Li i T 1:52 th Lori TI 3/54. 5.6.7 8 9 10 Occupation Time (min) Fig. 3: Position Accuracy as a Function of Station Occupation Time - 500 m Baseline 70 60 - 50 - 40 - 30 - 3-D Error (cm) 20 - 10 4 a 4°°5 60 172,8. 9,10 Occupation Time (min) Fig. 4: Position Accuracy as a Function of Station Occupation Time - 10 km Baseline 4.2 Use of GPS in an Urban Environment One of the major limitations of using GPS for GIS applications is the shading problem that is experienced under foliage and near buildings. Although it is an important concern for static applications, it is magnified for kinematic applications when a continuous trajectory is usually required. The susceptibility of GPS to shading is partially a function of the receiver that is used. For example, it is expected that a 12 channel receiver will generally be less susceptible 167

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