This section overviews the instructions required for the BAAM.Tech PPK system to function properly.
Quick Start #
Setting up the Base Station: #
The PPK needs a GPS base to provide corrections for the aircraft. Any base with GPS L1/L2 and GLONASS G1/G2, BeiDou B1/B2, Galileo E1/E2 and SBAS constellations will work. The Base station being used must be able to output a Rinex file with a 1 second observation.
- Setup the base station in desired location/position. Place the equipment outside and away from areas that could cause potential signal interference. Measure the height of the antenna from the ground. This measurement will be needed to use the BAAM.Tech Post Processing software.
- Turn on the base station and make sure the output has been setup for a 1 second observation Rinex file.
- If using a BAAM.Tech base station:
- The base station will come with a USB thumb drive inserted into the PPK box. No further setup is required. Power on and allow the system to acquire satellites.
Aircraft Setup: #
- The BAAM.Tech PPK system provides a USB thumb drive. Before powering on the aircraft, make sure that the Power and Signal wires are connected.
- The PPK system automatically turns on when the Aircraft does.
- It is recommended waiting 4-5 minutes after the system powers on. This will allow the PPK to acquire ample satellites before a mission.
A calibration panel is included with the BAAM.Tech PPK system. This panel is used to increase the accuracy of the data collected.
- Set the panel inside the project area and/or near your landing area.
- Before starting your mission, hover the aircraft over the panel and take a photo. This image will be used to calibrate the data during post processing.
Post Flight: #
- Power down the aircraft once it has safely landed. Leave the base station powered on. The longer the base station is left on, the more accurate your data can be once processed.
- Pull out the thumb drive from the aircraft PPK. Insert the thumb drive into your computer and check the file created. This file should be a .spb file dated with the correct Day, Month, and Year. The time will be corrected within the post process.
*Note that every time the aircraft is powered on, a new .spb file is written on the thumb drive. It is important to keep track of this to keep your files organized when processing data.
- Check the images collected to make sure they are up to standard for your project.
- If data has been successfully obtained, you can proceed to power down your base station. Check the thumb drive and make sure that a .spb file has been created.
Post Processing: #
- Create a folder on your desktop, and name it as desired (project name, flight date, etc. ). Within the folder created three folders labeled as follows : Rover, Base, Raw.
- Save your images in the Raw folder.
- Save your aircraft .sbp file in the Rover folder.
- Save your base station .sbp file in the Base folder.
- Open the BAAM.Tech Post Processing Software.
- At the top, click Load Rover
- In the first box, enter the Antenna Height of the PPK (make sure this value is measured in meters). The antenna height can be measured phase center of camera to phase center of antenna
- After height has been entered, click Browse to add your aircraft .sbp file. Your window explorer will open up, navigate to your project folder, and locate the .sbp file.
- Click Load and Confirm to convert to a Rinex file.
- Click Load Base
- In the Coordinate Options dropdown list, choose the Read Coordinates from Rinex option.
- Enter Antenna Height in meters. This measurement is obtained same as the aircraft (0.2038 m).
- Browse for your base station .sbp file and open file
- If you do not have your base location use Opus https://www.ngs.noaa.gov/OPUS/ to get an accurate location. If you have a spoof base file, proceed to the next steps.
- Load Base
- Click Process. This will take a while to process depending on file size.
- Once processed, open File Explorer, navigate to your project folder, and open your rover folder. You should have additional files added to your folder after the processing. Within these files will be a .csv file labeled “Event_Position”.
- Open the “Event_Position” file. Check the quality of the satellites and make sure the number of events match the number of images taken during flight mission.
- If the data is correct, return the BAAM.Tech Post Processing software and Click Geotag Photos.
- Click Browse, navigate to your Raw folder and open.
- Click the second Browse key, navigate to the Rover folder where your Event_Position file is located. Open the Event file.
- Click Geotag. Allow this data to process.
- Once processed, you will obtain another .csv file that will tag each image with its corrected GPS location.
- Start a new project and load images.
- In Image Properties: Set Coordinate System to EPSG 4326 and Vertical Coordinate System to Geoid Height Above WGS84 Ellipsoid.
- Select all images that are 1’s. Use the Event position file to determine this. They should correspond with the image number. If using a system other than DJI you can select all the images and rename them to start with numbers counting from 1.
- Set Geolocation accuracy to Custom
- Change Accuracy/Horizontal cells to 0.04m.
- Change Vertical/Horizontal cells to 0.04m.
- Repeat 5 and 6 for the 2’s but change the accuracy to 1.5m.
Adding in Calibration Panel: #
- Open GCP/MPT Manager
- Change Coordinate System to EPSG 4326 & Geoid Height Above WGS84 Ellipsoid.
- Open Event Position File and find the first image taken for the calibration panel.
- Click ADD, point, and copy the latitude and longitude.
- Enter Calibration Panel for the label.
- Altitude should have 0.04m subtracted from it, then add value to the altitude box.
- Use the Basic Editor to select all the images with GCP’s.
- Additional settings:
- Under Processing Options, set the value for “Minimum Number of Matches” to 6. This will reduce the noise in the project data.