UAS trajectory improvements for ground control

UAS trajectory improvements for ground control independence in photogrammetry

 

PhD student: Ben Grayson

Supervisors: Dr Nigel Penna, Prof. Jon Mills, Dr Darion Grant

Sponsor: EPSRC

Start Date: Sept 2014

 

Abstract: Large-scale photogrammetric mapping currently undertaken by the majority of unmanned aerial systems (UAS) is highly reliant on ground control points due to the limited precision of orientation systems. The imposed monetary and time-costs along with spatial operating constraints makes excluding ground control points from the workflow particularly desirable. This would also enhance applications such as landslide monitoring, forest change detection and rapid disaster response. Ground control may be reduced, if not removed, without loss of mapping accuracies if camera orientations (position and attitude) can be determined with better precision.

This study targets the GNSS (global navigation satellite systems) processing strategy, more specifically the adaptation of precise point positioning (PPP). In suitable conditions, regarding observations and processing, cm-level positioning is attainable by post-processing in a dedicated PPP software package. However, GNSS issues of data noise, cycle slips and short observation periods (for example) must first be addressed in the UAS environment. The quality of positioning will dictate achievable mapping accuracies, although the context and method of photogrammetric processing will also be strongly influential.