A UAV is like the drones which children and teenagers fly using a remote control box.
The Unmanned Aerial vehicle in the simplest form is the drones which children and teenagers fly using a remote control box; the complex end being the Predator MQ drones used by the US military forces for aerial reconissance missions. There are many types of this depending on the sector of use, range and budget.
How this UAV works and controlled from the base?
The UAV is shaped like a mini aeroplane,helicopter or a rectangular platform with
1.an area for payload(carrying objects- seeds in this case),
2.power source (lithium-polymer batteries,
3.camera and video link
4.components for reception of radio-transmitted signals
5.Sensors- these are basically position and movement sensors
6.Hardware and software - the UAV has a microcontroller, system on a chip or a single board computer and then. auto-pilot software.
For seed dispersal drones or UAVs, a pre-programmed flight path or fly on the wire like program signals are sent by a radio transmitter or by a radio telemetry device. These signals are then received by the receiver(built into the UAV). These signals coupled with inputs from the GPS are then transformed by the onboard flight controller board that actually decides how far up, forward, backward or sideward the UAV flies by driving the motors. At determined places, the seed release unit is activated, on which the seeds can be released to fall by gravity or with a propelled force that it can actually go a few centimeters below the soil.
Further details on seed drones used for Forestation programs can be found in this in-depth article (http://vc.bridgew.edu/cgi/viewcontent.cgi?article=1033&context=grad_rev).
How much load of seeds can it take with it for dispersing?
This depends on the vehicle design and capabilities for the actual payload. There are commercial drones that can plant 36,000 to 1,00,000 seeds a day. The average agriculture drones carry around 20 Kg payload.
Last year, an IISc team of experts, used drones that carried 5Kg seed balls in each unit and used on the Pinakini riverbank on the World Environment Day. Based on the quality of the seed and the seed survival pods, the success rates are variable, it was around 25% (IISC).
The most attractive part of this UAV seed dispersal or planting is that it costs just 15% of the human traditional method and is at least 10 times faster.