Geosciences
Auditing Geodetic Networks with Satellite Positioning
An advanced programme in planning geodetic control networks with static Global Navigation Satellite System (GNSS) observations, processing their baselines, adjusting them by least squares, testing their quality statistically, and converting ellipsoidal heights to orthometric heights with a geoid model.
Overview
About the programme
Duration
4 days
Delivery
Training room with field work
Language
Arabic or English
Objectives
Training outcomes
- Understand the error sources in satellite positioning: orbits and clocks, ionospheric and tropospheric delay, multipath and antenna phase centre.
- Plan a control network: geometry, observation sessions, independent baselines and connection to continuously operating reference stations.
- Process baselines and assess their solutions.
- Adjust the network by least squares, both minimally constrained and constrained, interpret the statistical tests and error ellipses, and detect outliers.
- Understand the national geodetic reference frame and the relation between ellipsoidal height, orthometric height and the geoid model.
Content
What the programme covers
Day 1: foundations and error sources
- GNSS constellations: GPS, GLONASS, Galileo and BeiDou, signals and frequencies.
- Code and carrier-phase observations, single, double and triple differences, and ambiguity resolution.
- Error sources and how to mitigate them, and precise orbits.
- Reference frames: ITRF, the Saudi geodetic reference frame (KSA-GRF17), epochs and station velocities.
Day 2: planning and observation
- Network design: geometry, redundancy, independent baselines, and connection to known points and continuously operating reference stations (CORS).
- Planning sessions and observation times according to baseline length and required accuracy.
- Field exercise: setting up receivers, measuring antenna height and keeping observation logs.
- Real-time kinematic (RTK) and network RTK: uses and limitations.
Day 3: processing and adjustment
- Baseline processing and solution assessment: fixed and float solutions, ratio and residuals.
- Loop closures and repeated baselines.
- Least-squares adjustment: minimally constrained adjustment, then constrained adjustment to known points.
- Statistical tests: the chi-square test, the tau test for outliers, error ellipses and relative precision.
Day 4: heights and auditing the report
- Ellipsoidal and orthometric heights and the geoid model (H = h − N), and global and local geoid models.
- Coordinate transformation between frames and datums, and transformation parameters.
- Auditing a network report: what it must contain and the common signs of problems.
- Final exercise on the data of a complete network, followed by the assessment.
Who it is for
Target audience
Surveyors and geodetic engineers, technicians responsible for control networks in government bodies, municipalities, survey companies and major projects, and reviewers of survey work.
Method
Delivery method
Lectures and calculation exercises, a field session of static observation with the organisation’s receivers where available, then processing and adjustment on the computer. Receivers and processing software are agreed with the organisation before delivery. Delivered in Arabic or English.
Questions
FAQ
Is particular processing software required?
No. The programme can run on the processing and adjustment software the organisation uses; the principles of processing, adjustment and statistical testing are the same across packages.
Can we work on data from our own networks?
Yes. The adjustment and auditing exercise can be built on raw observation files and earlier network reports from the organisation, if they reach the centre before delivery.
Who is the programme for?
For those who already work with satellite positioning and need a deeper understanding of adjustment and auditing. It assumes a basic knowledge of surveying and coordinate systems.
A programme tailored to your organisation
The duration and topics of the programme are adjusted to the organisation's needs, and it is delivered at its site, in a training hall arranged by the Center, or virtually.