TerraPOS Uses Precise Point Positioning to Provide Confident Airborne Kinematic Positioning Without Ground Reference

 

TerraPOS is GNSS (GPS+GLONASS) post-processing software capable of accurate positioning without the use of reference stations or DGPS services. Reference stations are made obsolete by employing precise satellite orbits and satellite clock corrections coupled with state-of-the-art error modeling.

 

TerraPOS is specially developed for kinematic applications, such as airborne photogrammetry or LIDAR operations, seabed mapping, or seismic surveying. When processing kinematic raw data of good quality, accuracy of 3 cm (horizontal) and 4 cm (vertical) RMS has been independently verified. The combination of great ease-of-use and this level of performance makes TerraPOS unique worldwide.

 

The software suite is based on the principle of Precise Point Positioning and has been developed by TerraTec of Norway

 

“It works anywhere in the world. Setting up base stations for projects in remote areas or for corridor Lidar work has always been a major cost factor”, says Oivind Aase, president of TerraTec, “Weather turning bad or suddenly clearing makes flying-in a ground crew to remote locations an expensive logistical nightmare.”

 

Unlike other software packages based on Precise Point Positioning, TerraPOS delivers cm-level positioning reliably and confidently. Great efforts have been made to rigorously implement the latest algorithms.

 

Operation

When using a survey-grade dual-frequency GPS receiver, the positioning accuracy with TerraPOS is reliably predictable by the duration of GPS data collected. Data sets should be preferably more than 3 hours long. If missions will be shorter, one can run the GPS receiver in the plane on ground power before or after the flight to extend the data logging period. After 24 hours of the mission the freely available precise orbital parameters are automatically downloaded within TerraPOS from the internet.

 

Typical kinematic accuracy with TerraPOS

 

  

Output

All internal computations are done on the ITRF datum, the International Terrestrial Reference Frame. The results are then transformed to many different datums and output in various formats within TerraPOS. This flexibility is crucial to integrate into an existing map production workflow. For example, through the Waypoint CMB file format TerraPOS data can be seamlessly imported into further GPS/INS processing.

 

“We fly 1-2 LIDAR missions daily and rely on TerraPOS to deliver us accurate GPS positions for our 7 million hectare forest inventory project”, reports Dr. Markus Rombach, Managing Director of Digimapas Chile. “It is a very cost-saving and relaxing situation to have an additional possibility to process our navigation data, independently of the functionality of our base stations”

 

Benefits

Not having to operate or sub-contract GPS base stations is a tremendous cost and time saver.

 

There are too many things that can go wrong when operating a GPS base station such as the crew not arriving on time, flat batteries, defective data cards and so on. Some problems become apparent only at data processing time. TerraPOS is able to save projects even when they have been flown months ago.

 

For corridors or large-area projects there is no need to set-up multiple base stations. There is no accuracy degradation due to baseline effects since there are no distances to base stations. Positioning is homogenous throughout the project area.

 

For international projects having to rely on local land surveyors to set-up a reference station is expensive and a risk that is completely eliminated with TerraPOS which works world-wide with the same accuracy.

 

TerraPOS is sold and supported by Frontier Geomatics Inc. For more information contact Roman Kathofer at RomanK@FrontierGeomatics.com or call +1-905-478-1208.