Sect_10.1.2

10.1.2 GPS and Quality Issues

QUALITY ASSURANCE PROCEDURES

Two important aspects of QA are highlighted here:

the importance of documentation and reporting, and

checklists that "track" the application of QA procedures from the beginning of a project to its completion.

Documentation and Reporting

In many countries geodetic control surveys are carried out by professional surveyors in private practice or government service. Appropriate reporting, documentation and archiving standards should be maintained in order to provide the client with a clear overview of all aspects of the survey "job". In some countries the results of geodetic control surveys are to be reported to the geodetic authority in a prescribed the format.

The following comments may be made:

A written report should be prepared, and signed by the surveyors in responsible charge of the project. It should include, as a minimum, the following data:
- A narrative description of the project which summarises the project conditions, objectives, methodologies, QC/QA procedures, and conclusions.
- A discussion of the observation plan, equipment used, satellite constellation status, and observables recorded.
- A description of the data processing performed. Note the software used (version number, etc.) and the techniques employed (including ambiguity resolution), and error modelling.
- Provide a summary and detailed analysis of the minimally constrained and the constrained Least Squares network adjustments performed. List the baseline observations and parameters included in the adjustment. List the absolute and standardised residuals, the variance factor, and the relative error ellipse/ellipsoid information.
- Identify any data or baseline solutions excluded from the network with an explanation as to why it was rejected.
- Provide details of the transformation model used, or derived, and any GPS/geoid height information that was determined.
- Include a diagram of the project stations and control points at an appropriate scale. Descriptions for each of the monuments should be included, perhaps accompanied by photographs.
Data files, including observations, computed baselines, network adjustments, and coordinates, if not submitted with the project report, should be archived for inspection and future analysis (perhaps in the SINEX format -- section 9.3.7), as should all field sheets and other reconnaissance information.

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