Automatic closed-loop control drone agriculture

Crops require consistent fertilization and spraying in order to maintain high yields. Traditionally this was done manually, with vehicles, or even via airplane. These methods are not only inefficient, and burdensome, but they can be very costly as well.
To increase safety and provide cost-effective work among the farmers, you are assigned to change the manual fertilizer spraying method to automatic fertilizer spraying method by using a drone. Note that there are two ways to fly a drone which is, manual and automatic. In order to perform automatic closed loop control system, automatic control must be take place. 
Automatic control in this context means you will use waypoints to fly your drones. You need to control the drone’s height (level) and speed and also take into account the disturbances. 
The design of automatic closed loop control system are comparatively complex than the manual ones. Such system takes feedback from output and performs the required action accordingly. The entire construction requires a sensor for taking input, some sort of controller which performs the action and a feedback taken from the output. 
  
Your design report should include (for height and speed control):
  
1. Introduction
a. System background (briefly explain on how to control a drone / how to fly a drone) 
b. Justification of using automatic closed loop control rather manual control.
2. Identify all the variables involved 
a. Controlled variable
b. Manipulated variable
c. Disturbances
3. Identify all the elements/instruments used 
a. Controller
b. Final Control Element
c. Process/System 
d. Sensor
4. Draw equivalent signal block diagram for the system
5. Explain the closed loop control system
6. Sketch the expected dynamic response 
7. Briefly explain the advantages of automatic control in industry
8. Conclusion