Reduces or eliminates the need for ground control points!
Serious professional mapping with UAVs demands high precision and accuracy. Up to now, serious mapping operators face a choice between buying survey grade GPS equipment and placing lots of precision ground control points (and in many cases, recovering them after the flight), spending $10-20,000 on Aeropoints and having to lay them out and collect them every time, or spending money on new drones fitted with OEM RTK or PPK GPS systems.
And there’s a bigger challenge too … systems using RTK (e.g. Emlid Reach and Aeropoints) only use a single GNSS frequency, so they are prone to multi-path errors in heavily treed or built up areas, and their data cannot easily be corrected if you find out after the flight that it was not accurate.
Now there’s a better choice, and it makes sense because it’s the choice designed by UAV mapping professionals with over 100 years of combined mapping experience.
The BAAM Tech PPK system can be retrofitted to your DJI Phantom 4 Pro to reduce or even eliminate the need for precision ground control. If you’re not familiar with PPK (Post Processed Kinematic), it’s a high accuracy GPS system that simplifies your workflow because all of the precision work is done after the flight, using an online corrections system.
It’s much easier to use than RTK because you simply plan your flight, start up the aircraft and conduct your mapping flights as you do right now. The PPK system adds locational data which is post-processed after the flight, using the software provided, correcting the location of every image to centimetre precision using either a base station or a CORS network station for corrections.
Mapping professionals have much more flexibility over where the drone is used, how they lay out flight grids and the area which can be mapped in a single mission using PPK than with any other corrections system currently available.
It’s also much easier and faster (up to 75% faster) to get accurate survey data using PPK over traditional ground control points (GCPs) or Aeropoints, so your time can be more productively and efficiently used.
High Accuracy Multi-Constellation GPS
While RTK integration options typically use only L1 GNSS data, the BAAM Tech PPK system for the DJI Phantom 4 Pro uses GPS L1/L2 and GLONASS G1/G2 GPS data, supplemented by BeiDou B1/B2, Galileo E1/E5B and SBAS constellations.
The use of multiple satellite positioning systems greatly increases the GPS signal quality to provide the most accurate UAV positioning data, especially in “noisy” urban environments.
Accurate Geo-Tagged Images
The BAAM Tech PPK system has overcome one of the biggest limitations of integrating RTK/PPK into the Phantom 4 Pro by connecting directly to the shutter of the DJI camera and calibrating to ensure the geotagging is of the highest quality.
Each PPK system includes BAAM Tech’s easy-to-use post-processing software that will make the required corrections to image positions by calculating the actual location of the UAV when each image was captured, using either a local base or a CORS base station. The corrected data is used to update the EXIF data with precise geo-locations and you can process the imagery as you do now.
One System for Ground and Air
Because the BAAM Tech PPK system comes with an easily removable module, the same unit can be used as a ground rover to collect GPS data for precision ground control points, before being slid back into the aircraft for PPK precision mapping flights.
This removable modular technology significantly decreases the cost of precision surveying by allowing the same system to do both air and ground position corrections. A base station version is also available for base-rover configurations.
Frequently Asked Questions
Why is the Phantom 4 Pro PPK system better than RTK alternatives?
RTK (Real Time Kinematic) positioning systems rely on making real-time corrections to image positions while you fly. PPK (Post-Processed Kinematic) makes all its positioning corrections after the flight. RTK-equipped drones require a stable base station radio link at all times to make in-flight corrections and are more prone to errors due to distance between the base and the UAV, GPS signal reflections off buildings and trees, etc. If the radio link between an RTK-equipped UAV and the base is disrupted, critical image positioning data is permanently lost and the rest of the flight will have missing image positioning data. The only way to recover from this is to repeat the flight and hope the connection issue is not repeated.
Multi-constellation PPK systems are faster to acquire a position fix and more reliable at holding their position fix during flight than single frequency RTK alternatives. Dual frequency PPK receivers can more quickly determine ionospheric conditions and calculate a high accuracy fix. This also allows them to recover from a loss of fix and pick up new satellites as they come into view more quickly. PPK-equipped drones process the positioning information after the flight, so there is no risk of data loss due to radio interference. PPK also tracks back and forth between position data multiple times to collect more comprehensive positioning.
Do I need a base station to achieve centimetre accuracy with the BAAM Tech PPK system?
No, it is possible to use the PPK system in your Phantom 4 Pro on its own, in conjunction with a CORS network station location within 7-8km, and achieve around 6cm positional accuracy. It is easier and more functional to use a second BAAM Tech PPK or other dual frequency GNSS system in a base/rover configuration for greater range and positional accuracy. The minimum observation rate at the base station should be 1Hz.
Complete PPK Survey System
We recommend using the DJI Phantom 4 Pro PPK module in conjunction with the BAAM Tech PPK Base and Rover system to facilitate easy placement of ground control points (you may still need 3-4 for absolute precision) and PPK flight within the same simple workflow and post-processing software.
Take a look at our PPK Base and Rover System – low cost, high precision page for more information.
The BAAM Tech PPK system for the DJI Phantom 4 Pro costs less than A$4000 (plus GST) installed (cost will depend on exchange rates at time of purchase). It costs no more to buy the BAAM.Tech PPK system from Queensland Drones.
To find out more about getting PPK GPS precision added to your Phantom 4 Pro fleet, contact Queensland Drones using the links below.