Camera Positioning System
A generic PPK (post processed kinematic) camera positioning system that integrates with most cameras on any UAV or manned aircraft. PPK produces high accuracy GNSS (GPS plus Glonass) camera positions to increase photogrammetric mapping accuracy and reduce ground control requirements.
The key to accuracy in any mapping or 3D modelling project is control. This can be either GCPs (ground control points) visible in the photos, or CPs (camera positions) where each photo was taken. Enabling your mapping data acquisition with accurate CPs can reduce or eliminate the need for GCPs, saving on ground survey crew time and cost.
How It Works
The PPK hardware operates independently of your current UAV flight management system. Your UAV will fly as it does now, with onboard flight control using the existing autonomous GPS. The PPK system logs precise carrier phase GNSS data with millisecond camera trigger events to provide highly accurate camera positions after post processing.
PPK requires base station data to process against. You will need a survey grade GNSS unit logging data in the vicinity of the project, or you can download data from a local CORS station. A base receiver can be supplied if required.
After post-processing, the high-precision camera coordinates are input into your photogrammetry software (such as Agisoft or Pix4D), along with your images. With centimetre level camera positions, the mapping and modelling you produce will have the highest possible accuracy.
Typical geo-referenced UAV systems implement real time kinematic (RTK) solutions using various grades of GPS receiver. RTK requires a stable radio link to receive base station data which is processed on the fly. Particularly with UAV flight dynamics, RTK can be prone to GPS signal blockage and radio link outages. This is apparent where signals are obstructed or over long distances, where loss of correction data and initialization result in a smaller percentage of accurate camera positions being determined.
An alternative to RTK is post processed kinematic (PPK), where data is logged in the UAV and processed with base station data after the flight. There is no data loss or initialization loss as in RTK due to radio link limitations. All collected data is processed with similar algorithms to RTK, but forwards and backwards through the data. This ensures the most robust results possible.
PPK offers greater flexibility in operations, longer range from the base, is more reliable, more accurate and easier to use.
for Precision Agriculture
with minimal GCPs
High spec Novatel GNSS board
Triple frequency L1/L2 GPS/Glonass
- 2cm horizontal and 5cm vertical camera position accuracy after processing with base station data (no radio link required).
- reduce or negate ground control survey requirements.
- produce highly (absolute) accurate DTMs and georeferenced orthos
- Lightweight UAV version or ruggedised metal enclosure with additional outputs for manned aircraft.
- Process with Rinex data from a known base station
- Use your own survey grade GNSS receiver or purchase our dedicated base model
- Process with Rinex data from a nearby CORS station
- Use satellite broadcast corrections such as Omnistar or Terrastar
|L1 L2 GNSS||L1 L2 GNSS||L1 L2 GNSS|
|by Novatel||by Novatel||by Novatel|
|light active antenna||Aviation approved active antenna||active antenna|
|USB and serial outputs|
Post Processing Software
Dedicated, custom developed software for PPK post processing and extracting photo centres from post processed data. The software runs forward and backward processing for smooth and precise results.
Software supplied free with hardware.
- Dependent on distance from base station
- Camera position accuracy 3cm horizontal and 5 to 10cm vertical plus 1ppm
- Aircraft flight dynamics contribute to absolute camera position accuracy.
- For orthomosaic generation (2D), no GCPs are required
- 2 or 3 GCPs are recommended for accurate 3D modelling (to 5cm) to manage camera
focal length errors
Manned Aircraft Flight Management System and Mission Planning
- proven software developed in Australia
- integrated into onboard computer
- flight control with pilot display
- integration to autopilot
- data logging