Installation of the DLS onto your drone should be done by mounting the DLS onto the top of a pole attached to the drone. The height of the pole needs to be such as to place the DLS above any sources of shadowing from the drone, such as propellers or other equipment, from any angle the drone will be flying at.
If a GPS module is used, it is also typically located on top of the aircraft. It is expected that the GPS Module will be mounted close to the DLS as the cable that connects the two is short. Secure any excess wire length between the DLS and the camera with a tie.
The GPS module should be mounted on a pole or similar structure to avoid magnetic fields generated by electrical equipment on the aircraft.
Figure 2: (Left) DLS and GPS correctly mounted,
(Right) GPS mounted incorrectly above DLS
The configuration on the left shows a proper mounting style. The top of the DLS is seated above (or at least at the same level as) the GPS module and away from any shadowing. The configuration on the right shows the DLS under the GPS module, which may cause the GPS module to cast a shadow over the DLS and produce incorrect irradiance data.
You may also choose to mount the DLS and GPS module on the same pole, the images below show an example of this mounting configuration.
Figure 3: DLS and GPS mounted together on one pole
It is critically important that the GPS module be mounted away from electric current sources which can produce electromagnetic interference (EMI), such as batteries, wires, and other electrical equipment on the drone. See section 5.5 for how to perform a magnetic interference check after calibration.
The figure below shows an example of a GPS module mounted away from potential interferences.
Figure 4: GPS is outside of potential magnetic interference
Fixed Wing Installation
Installation of the DLS and GPS module onto a fixed wing platform will likely require the units to be mounted on the drone itself, as attaching a pole to the drone may not be a viable option. The DLS should be installed such as to prevent shadowing by any parts of the airplane.
It is critically important that the GPS module be mounted away from electrical current sources which can produce electromagnetic interference (EMI), such as batteries, wires, and other electrical equipment on the drone. See section 5.5 for how to perform a magnetic interference check after calibration.
Figure 5: DLS and GPS installation on a fixed wing airframe
The DLS should be mounted such that the arrow on the top surface is pointing forward (in the direction of flight) and is aligned with the direction of the GPS module. The figure below shows an example configuration.
Figure 6: DLS and GPS with front facing arrows shown
Also, the DLS should be mounted such that in straight and level flight (fixed wing aircraft) or hover in no-wind conditions (multicopters/helicopters), the top surface of the DLS (and GPS module if used) is parallel to the horizon (pitch and roll angle of approx. zero with respect to the earth). The figure below shows an example of a DLS and GPS resting on a surface parallel to the surface of the drone in hovering flight.
Figure 7: DLS is mounted parallel to the ground
The pole on which the DLS is mounted should have a smooth flat surface plate that can be used to mount the DLS (and GPS module).
Whatever pole or poles are used to mount the DLS and GPS module should be sturdy enough to hold the weight of the units and not vibrate/oscillate during flight.
Orientation When Using a Pixhawk/Autopilot
When attitude information is coming from an autopilot or payload computer, it is very important that the orientation in which the DLS is mounted mimics the X and Y plane of the autopilot. Otherwise the pitch, roll, and yaw data from the DLS will not match the data the autopilot is reporting.
Use either double-sided tape (a strong-adhesive tape such as VHB is recommended) or the two screw mounts to secure the DLS to the top of the pole or the aircraft (if using a fixed wing). The screw holes are sized for a #2 or M2 screw or bolt.