3p/3PX Flight Checklist
Check the weather conditions of the area you intend to fly.
Ideal conditions for data collection are sunny or overcast skies (uniform lighting conditions), within a few hours of solar noon.
SLANTRANGE sensors are not designed to be waterproof; do not fly in the rain!
Given the hard mount, sensor orientation is at the mercy of aircraft orientation: in gusting conditions, fly with more overlap (25-40%) to ensure complete coverage in the midst of aircraft attitude (pitch, roll, yaw) variation.
If it is too dark to see your shadow, it is likely too dark to collect high quality data. The sensor is measuring the interaction of plants with sunlight; less sunlight means a higher signal to noise ratio and thus lower quality data. Additionally, darker conditions result in longer sensor exposure times, and thus slower flight speed to prevent image blur. If flying in overcast or darker conditions, decrease flight speed to compensate, especially if flying at low altitude or collecting population data.
Ensure proper sensor mounting and hardware setup.
The pitch of a multirotor aircraft in forward flight is a function of air speed. The AIS and field sensors must be mounted at an angle to compensate for forward pitch, so that the field sensor looks directly downward and the AIS looks directly upward. Significant increases or decreases in flight speed may affect the pitch angle of the aircraft. If you fly missions at significantly different airspeeds, adjust the mounts for the different flight plans to keep the AIS and field sensors oriented zenith and nadir, respectively.
Clean any dirt from the sensor window (remove the protective film from the sensor window if you have not already done so). It is advantageous to take off and land on some sort of landing pad: e.g. a heavy canvas, plastic sheet, plywood, or otherwise to prevent dirt from blowing up onto the sensor window.
Ensure the Field and AIS sensors are mounted in accordance with the Mounting section of this guide, and connected via the AIS cable, and all wires are secured to prevent contact with propeller blades.
Ensure the SD card is inserted in the field sensor.
IMPORTANT - Do not insert or remove the SD card while the sensor is turned on. This will cause the SD cards checks to be bypassed and improper saving of data resulting in possible sensor failure.
DO NOT fly missions by hand. Program your mission using mission planning software.
For best results, we recommend flights with at least 6 minutes worth of in-flight data. SLANTRANGE systems are optimized for collecting large amounts of data quickly and efficiently. With small area coverage flights that have less than around 500 images, some data processing steps are not optimized. If flying test plots or other low area coverage crops, we recommend flying lower, slower, and with more overlap, to gather at least 6 minutes worth of in-flight data.
The standard 8-10 degree mount of the sensor and AIS are not optimized for flight speeds above 12 m/s. If flying faster than 12 m/s, increase the angle of the sensor mount as needed (also taking into consideration the wind conditions, other payloads on the aircraft, etc...) to keep the sensor and AIS parallel to each other and the ground in forward flight.
Refer to the user guide section Mission Planning to determine flight altitude and velocity settings that will generate data products tailored to your crops in their current growth stage. For example from the Flight Plan by BTC app, if flying a corn field in a population stage with plants that are 5 cm x 2 cm the recommended flight parameters look like:
The sensor must fly forward throughout the data collection ("lawnmower" pattern). Make sure the aircraft is programmed to turn 180 degrees at the end of each flight leg. Do not fly forward on one pass, crab to one side, then fly backward on the next pass.
Plan flight legs to extend slightly beyond the edges of the field you are mapping so your aircraft has time to reorient to the new heading, accelerate to its prescribed speed, and level off for a straight and stable flight leg before flying over the area of interest. (The pitch and roll of the aircraft can make images taken during turns unusable for map generation.)
Three variables to optimize if possible, in order of importance:
- In the presence of a crosswind, fly perpendicular to the wind to maintain a consistent aircraft roll angle. Flying parallel to the wind can cause large differences in aircraft pitch or ground speed on legs flying directly into and away from the wind. If the aircraft is noticeably affected by the wind, plan your flight to compensate and do not worry about the next two items.
- Plan your flights with legs across the long dimension of the field. Flying across the narrow dimension of a field in short passes results in more turns, longer flight time, and thus lower area coverage.
- If imaging row crops with significant bare soil content visible between rows, fly parallel to the crop rows.
Make sure your aircraft is programmed to fly above power lines, trees, or other obstacles at the edges of the field!
Turn on the sensor.
After the SD card check is successful, the yellow light will begin to blink indicating pre-flight checks are being performed. Once the checks are complete solid green, yellow, and red lights will appear on the AIS.
If this is your first time using the sensor, or the sensor is over 500 miles away from the location of its previous calibration, or you have the sensor mounted on a new aircraft or on an aircraft with new hardware, use the 3p Toolbox app to calibrate the sensor compass. See the previous page, 3p Calibration, for details.
Start data collection.
Press and hold the AIS button down for approximately 1 second, until you see the yellow light only. The blinking yellow light will turn solid green, indicating the sensor is initializing the session and cameras. (If using a 3PX and the Flight Plan by BTC app, you can start collection by pressing the capture icon )
Once the solid green light begins blinking, data is being collected and the sensor is ready for flight.
Start the mission and takeoff!
Observe the aircraft during flight ensuring that it is flying as expected.
Verify the aircraft is turning after each leg and flying forward.
Land and stop data capture.
Upon landing, press button on the AIS sensor and hold for about 1 second, until the light turns yellow.
Wait for about 10 seconds for simultaneous green, yellow, and red lights appear, indicating the data sessions has been completed. During this time the cameras are stopping capture and log files are being created.
Shutdown and download data.
- Remove power from the sensor, then remove the memory card from the sensor and insert into the computer to transfer the data.