Tethered UAV achieves simultaneous air-ground mapping

October 20, 2016  - By

Geonumerics reported a mapping benchmark achieved in June 2016: operation of a tandem aerial-terrestrial system conceived for simultaneous geodata acquisition in corridor mapping missions.

The mapKITE system tests were carried out at the BCN Drone Center on 2,500 hectares of segregated airspace outside Barcelona. A 2-kilometer rural road served as a testing corridor and was operated successfully around ten times. The testing site was prepared with several ground control points for quality checking.


Kinematic ground control point enables tandem ground-air mapping via sensor orientation and calibration.

Tethering the UAS to the terrestrial vehicle. By means of a real-time navigation system, the terrestrial vehicle generates the basic source information for generating waypoints to be followed by the aerial platform. Schematically, for every terrestrial position, a geometrical shift is applied to keep a particular relative air-ground geometry. A “follow-me” scheme keeps the UAV coordinated as the vehicle moves; the tether is set to maintain a constant relative speed.  Additionally, the ground vehicle is observed in  most of the aerial images.


Top, left and right: mapKITE aerial images from the corridor flown at the BCN Drone Center (June, 2016); bottom: 3D model extracted from aerial images only.

Linking the two with an optical target. An optical coded target on the roof of the ground vehicle is automatically identified and measured in the aerial images in a fast and robust manner. Its goal is twofold: firstly, it enables a complementary guidance scheme based on target-tracking,  adding robustness to the virtual tether. Secondly, the image measurement of the optical target together with the high-quality trajectory of the ground vehicle introduces a kinematic ground control for a posteriori sensor orientation and calibration.

By performing photogrametric pointing-and-scaling measurements of the optical target, and linking these with the precise terrestrial vehicle trajectory by means of image synchronization in a common time reference, mapKITE introduces an analogy to the conventional ground control points (GCPs)  ready-to-use kinematic ground control points (KGCPs) for every image.

Equipment used in the first mapKITE campaign Fundamental mission parameters
Aerial camera Sony NEX-5 (c=20mm) Gruond Sampling Distance 2,4 cm
GNSS receiver (UA) Javad TRE-3 Flying altitude 100 m
TV navigation system Applanix POS-LV420 Forward image overlap 80%
TMM system Optech Lynx Image footprint 120 m across-track

More information can be found in the following material:
•    download the PDF mapKITE brochure with more information about the test campaign.
•    The video of the mapKITE test campaign explains the system and the performance test.

GeoNumerics is a research and development company specializing in geomatics and accurate navigation, located in Catalonia, Spain. The company licenses software and provides R&D services focused on applications of unmanned aircraft, Galileo satellite navigation and inertial navigation in remote sensing and mapping.


Point cloud obtained with the terrestrial mobile mapping system.

MapKITE is currently being developed by an international consortium within the frame of the project “mapKITE: EGNOS-GPS/GALILEO-based high-resolution terrestrial-aerial sensing system“. The project is funded by the European Commission (EC) through the European Union (EU) “Horizon 2020 Programme for Research and Innovation,” supervised by the GSA on behalf of the EC, and coordinated by GeoNumerics. The mapKITE consortium includes ten organizations from five European countries and Brazil.

Watch a video here:

mapKITE: Total 3D mapping – Simultaneous aerial and terrestrial from GeoNumerics on Vimeo.

Photos: Geonumerics reported

This is posted in GIS News, Mapping

About the Author: Alan Cameron

Alan Cameron is the former editor-at-large of GPS World magazine.