GNSS PPK UPGRADE
Yes. Any Dual Frequency GNSS base station will work with the system. The GNSS system is based on post processing (PPK) and thereby eliminates the complexities involved with RTK (Real Time Kinematic) radio links as well as reducing the over-all weight the drone, while still providing the same level of accuracy. Minimum observation rate required at the base station is 1Hz. Alternatively, you can subscribe to a positioning service to obtain virtual reference station data. We can provide an extra GNSS receiver to be used as a base station. Please contact us for more information.
As average 5-10 cm accuracy can be achieved for 50 Has using 4 GCPs. For each extra 25 Has one GCP is required to maintain this level of accuracy. Increasing the number of GCPs will increase the accuracy even more.
This solution has few limitations other than those inherent with GNSS. These limitations include operating in GNSS denied or compromised environments as well as the typical GNSS error calculation of 1cm + 1ppm (part per million) x baseline (distance between base station and rover). As long as the distance between the base station and the rover is under 20KM the GNSS positional accuracy should be within the typical 1-3cm range. If you are interested in purchasing this receiver on its own and integrating it with your own system, it is recommended that the receiver remain at least 12cm away from any GPS antenna so as to avoid any EMI (electro-magnetic interference). We provide a voltage regulator along with the purchase of this solution which can handle voltages between 6 and 26V. This solution can have WAAS, EGNOS, SBAS and a few other augmentation services enabled upon request. Please let us know where you are located and which service you are looking for so that we can verify its availability.
For PPK GNSS you are required to use a physical ground station over a known (or to be determined) point. The coordinates for this point must be available when performing the post processing of the aerial data. This PPK solution does not require any radio link between the two receivers, only that the data observed with the aerial unit falls within the time frame of the data observed on the ground side. If you do not have a GNSS receiver to use on the ground side of this operation, a second aerial unit can be used for this purpose.
If you don’t have a base/reference station then you could use a positioning service such as available in the States or in Canada. This service, for example, is offered by the National Geodetic Survey (NGS) and is called the Continuously Operating Reference Station (CORS) system (http://geodesy.noaa.gov/CORS/). I do not know if you have such a service in your location or wherever you plan to use the UAV at but the way it would work is, after your flight, you would download the closest CORS RINEX data and use that as your base station data for the post processing. Please keep in mind that it is recommended that this reference station not be more than 20km away as beyond that you will end up increasing the expected errors.
For SfM processing the attitude information only helps speed up the alignment process. There is no more accurate and affordable way to determine the precise orientation of the photography than by running it through an SfM program such as Agisoft Photoscan or Pix4D. If however you intend to use the photography and precise camera exposure positions provided by the GNSS PPK receiver in traditional photogrammetric software the orientation (Omega, Phi, Kappa) data may be required. To get this information, we recommend running an image alignment process through SfM software (such as those programs mentioned above) and then exporting the orientation information. With a little bit of work in Excel, this orientation data can be added to the images precise positions and then imported into Photogrammetry software.
This is also the approach that some of our customers who are using traditional photogrammetry software are following and are experiencing great results.
Yes, but it has an additional cost. Please contact us for details.
Yes! We also sell the PPK system so that you can install into other existing drones, fixed wing or multirotor. You just have to make sure your drone can lift 120 grs of extra weight, that it can carry a hot-shoe capable camera (like a Sony a6000), that the GNSS antenna can be located aligned with the center of the camera lens (vertical distance between the two is irrelevant) and that you can provide 5V- 36V DC to the GNSS board. Also the PPK board needs to be at least 12cm away from other GPS receivers.
Physical installation can`t be easier. One of the best features of our PPK system is that it does not integrate to the autopilot, it is basically a plug and play system. So it doesn`t matter what autopilot you use. All you need to do is connect it to the hot shoe of the camera and make sure your autopilot fires the camera.
Every time a picture is taken the camera generates a signal on the hotshoe. The PPK system marks the “event” coordinates at a very high accuracy level. Then during GPS post processing (instructions provided), the images will be geotagged and left ready for image processing (DSM Models, orthomosaics, point cloud, etc) at 3cm accuracy in XY and 5cm accuracy in Z.
Yes, we do provide hands-on flight training as well as online training to our customers. Typical UAV hands-on flight training takes two days, is performed in the flight field and all aspects of aircraft preparation, preflight checklist, mission planning and flight are covered. The student gets to create their own flight plans and fly them, with the assistance of the instructor. No image processing training is included. Customers are advised to schedule to come to Ontario- Canada for at least three days, to have an extra day in case of rain.
Most of the times the training is not necessary. The UAVs and delivered ready to use, flight tested and with a complete and very detailed user Manual with lots of examples, videos and photos, checklists, and data covering every aspect of the flight, including examples to make your first flights. It is completely possible to get your UAV airborne with no problems even if the user has no experience. Just follow the steps indicated in the manual and double check your mission before flight according to the examples given.
Over the years we have seen that after customers make their first 2-3 flights solo they understand how easy is really the system to operate and they are pretty much ready to start making real missions.
Since our UAVs use a conventional configuration airframe (meaning that separate wings and tail are used) the required roll is minimal during crosswinds, making them very stable platforms. The crosswind is handled mainly by the rudder or V-tail only, leaving ailerons free to control the level. Unlike flying wings (tailless configuration), conventional configurations are much more stable and have independent yaw control to compensate for crosswind situations. Therefore we don’t consider necessary to add camera gimbals inside the UAVs.
The autopilot triggers the camera by distance. When the user is creating the mission the Survey Tool will ask the user to select the target area, enter the altitude, overlaps and some camera information (which is provided in the manual). The autopilot then will calculate the distance between images, number of images, resulting ground resolution and other important fields which are displayed. You can see how your mission will look like even before flying and see changes on the mission in real time.
Since the user has control over these variables before the mission starts it is very easy to predict how your mission will end and how many images you will have to process vs. ground resolution.
The software required to create missions and to communicate with the aircraft during flight (data link) is the Mission Planner by Michael Oborne. The Aeromapper User’s Manual will provide you with all the instructions to download the software, create missions and in general use the software.
Creating a complete survey mission with the Aeromappers is very easy and it is actually one of the best features of the system. We have seen that our customers get really impressed by the power and simplicity of the software after they tried for the first time and they see the result during flight.
A full survey of several square kilometers even with waypoints at different altitudes can be created in seconds: just click on the map to select the target area (google earth), select altitude, overlaps, orientation of the lines and enter the camera settings according to your User’s Manual and the autopilot automatically calculates:
Flight lines and distance between them.
Total distance of flight
Distance between images
Total number of images
After this the mission can be reviewed and the takeoff altitude entered. The mission is then ready to be sent to the autopilot wirelessly via the data link. Examples of missions with lots more of information is covered in the User`s Manual.
The parachute is operated from the remote control so ultimately the human pilot has control over it. Is up to the pilot to decide the best moment to deploy the parachute. Detailed explanations are included in the User’s Manual.
When the UAV has completed the survey lines it will head to the selected landing spot and perform a series of over passes at usually 40m of altitude, then climb, go around and pass again at 40m. This recovery “pattern” is planned by the user according to the location and wind direction, and it is very easy to do. In one of the passes the pilot deploys the parachute.
The parachute can alternatively be deployed automatically at a waypoint if necessary.