Module 2: Equipment
Lesson 1: Parts & Purpose
AIFS Drone Curriculum Package
At the end of this unit, students will be able to:
What is the basic equipment that all drone pilots will utilize?
1
The drone
2
The controller
3
The Camera/Sensor
The Drone
The drone is a basic piece of hardware and we will be referencing its parts as basic equipment to understand its use and function. We will focus our attention on multirotor drones and sensors as they are most familiar to our group, used widely, and readily available “off the shelf”. Fixed wing drones are available and historically have been the precursor to the technologies in use today but our focus will be on the multirotor.
We’re reviewing hardware that is:
Equipment- Drone Parts
RTK GNSS (if no RTK, the top is the location of the GPS)
Chassis/Hull
Propeller
Motor
Forward Obstacle Avoidance Sensor
Landing gear / Antenna
Mounted Camera / Sensor
Gimbal 3-Axis
Flight LEDs
Mini USB Port and Mini SD disc slot
Battery (rear facing)
Downward Obstacle Avoidance Sensor (underneath rear)
Downward Ultrasonic Sensor (underneath rear)
Anatomy of A Drone - by DroneFly Anatomy of a Drone Infographic
Let’s take an outside & inside look of an exploded DJI Phantom 4 (front and back) and its controller
Equipment- Drone Components
Antenna - Inside the legs of the drone is the transmission system which relays information from the drone to the controller and from the controller to the drone.
Battery - The power source for the drone. Drone batteries are ‘intelligent’ meaning that they have firmware that helps with overcharge protection, temperature data, charge cycle history, and communication of power output to the drone. This helps the operator avoid power problems during flight and the efficient repeated charging and discharging of the battery though its expected life.
Camera / Sensor - The picture provided shows a camera but various sensors may be mounted on the gimbal or underside of the drone. High resolution digital cameras and spectral sensors allow for the collection of data from overhead as the drone flies its mission. Greater detail is provided in the Supplemental Equipment Unit
Equipment- Drone Components
Chassis / Hull - The main purpose of the drone frame and chassis (or hull) is to provide adequate protection to keep the electrical components from harm while also providing enough rigidity and material strength to fly, land, and provide durability. The top materials used in drones today are carbon fiber-reinforced composites (CRFCs) especially in the frames, and thermoplastics.
Flight LEDs -These flash various colors to show the user what direction the drone is facing. The two flashing red lights show the front of the drone. The two green flashing lights are the back of the drone. Flashing lights also help in notifying pilots of manned aircraft of the vehicles presence. The safety lights have long-range visibility.
Equipment- Drone Components
Gimbal; 3-axis - A motor is placed on the 3 different axes around the camera or sensor. When the sensors detect motion on any of these axes, the motors counteract the motion to cancel it. This happens almost instantly as thousands of calculations are executed to provide smooth footage and stabilized collection of data.
Landing gear - Landing Gear for drones provides additional ground clearance. This can help protect the drone camera from damage. They can widen the drones "stance", allowing for a more stable take-off and landing.
Mini SD Disk Slot - While you can fly a drone without a mini SD card, you will not be able to store pictures, video, or sensor data. 32GB or 64GB memory cards are commonly used to collect image date.
Equipment- Drone Components
Mini USB Port - The port used to connect the aircraft to other equipment. While this port can be used to connect to the drone and read what’s on the sd card, its primary use is to upgrade the aircraft by connecting it to the controller using the USB OTG cable.
Motors - DJI uses brushless DC (BLDC) motors for all of their drones. These are industrial motors designed for multirotor systems (equal number of clockwise rotating and counterclockwise rotating).
Obstacle avoidance sensors - Front, rear, and bottom sensors are the main components of a drones vision system. These are used to maintain position, hover indoors, and operated in areas where GPS signals are not available.
Equipment- Drone Components
Propellers - Propellers have specific design consideration for each drone. Considerations include rotational direction, size of blade, number of blades, and pitch of blades. Propellers may have 2, 3, 4, and even five blades. Propellers, when turned by the motors, push air in a specific direction creating the propulsion needed for the aircraft to fly and maneuver.
RTK-GNSS - Real Time Kinematic positioning using Global Navigation Satellite System. GPS drones are equipped with a GPS module that allows them to know their location relative to a network of orbiting satellites. RTK follows the same general concept, but. RTK uses a fixed base station and a rover to reduce position error. The base station transmits correction data to the rover on a continuous basis allowing for the most accurate triangulation of drone position data.
The controller
The controller is paired with the drone and works by sending signals from the remote control to the drone. The signal tells the drone drone what operation to perform (rotate, forward, go up, etc.). Radio signals are sent from the radio transmitter in the drone controller and received by the drone's receiver via antenna that are either visible or embedded within the drone and the controller let’s look at a DJI Phantom 4 Controller
While controllers may vary to some degree, operationally, a drone is piloted by a pilot on this piece of equipment as it communicates with the UAV.
Controller (DJI P4 Pro & Pro+ pictured)
Pilot’s Controls
Each drone will have it’s own controller and will be paired to it for pilot control. Models vary by make and model of drone but all have some basic features needed for flight operations.
Screen view
Controllers may come with a screen readout, ready for your tablet or phone to have screen readout, or may not have a screen capabilities (smaller and indoor) Some drones can be fully controlled by a cell phone device.
Antenna, buttons, toggles, and more
Every controller has some basic controls needed to communicate with UAV and guide its activities. Like driving a car, you will need to familiarize yourself with the controls and practice the operations for smooth operation of the vehicle
Sample Controller Components courtesy DJI
Sample Controller Components courtesy DJI
Sample Controller Components courtesy DJI
Sample Controller Components courtesy DJI
The Camera and/or Sensors
Sensors and sensor technology is a basic component in Unmanned Aerial Vehicle (UAV). It is common for a drone to have many of the following sensor technologies embedded within. A 3 axis accelerometer sensor to help stabilize the drone. A.gyroscope sensor is used to provide angular motion to the drone. A Magnetometer sensor present in the drone that has GPS functionality. A Barometer sensor (or pressure sensor) to determine the height of the UAV. A GPS sensor that uses satellites that have been launched around the earth to determine specific geographic locations. A Distance sensor used to help detect obstacles in the path of the UAV. There are more and the list is quite extensive. ONe could say that sensor technologies are what have enabled UAVs to take flight and be utilized in the fashion that we rely on today. Our focus in this unit, however, is the camera or sensor equipment we mount on our UAV to enable data collection needed for solving problems in the field
We’re reviewing hardware that is:
The Camera is a sensor
Cameras or Sensors mounted on our UAVs rely on specially made sensors to detect and convert Electromagnetic Spectrum (EMS) signals or waves into digital images that we can use to analyze problems or create useful artifacts. For better understanding, we will use the term “sensor” (and oftentimes the sensor type, like “RGB”) to address the equipment we mount on our UAV (drone) to capture digitized image data.
To better understand the equipment and the work we do in agriculture with UAVs, it is important to share a basic introductory knowledge of the electromagnetic spectrum (EMS), both visible light rays and non-visible light waves. NASA provides a nice introduction for us to follow:
UAV Image sensors
One primary usage of UAVs, especially as it relates to agriculture, is to collect high quality images, from both visible and invisible portions of the electromagnetic spectrum, in order to obtain a high level of detail and data that can be interpreted and analyzed. This data can then be further processed to make good business decisions, detect trends and predict future changes or potential issues that might arise.
The cameras and sensors used in UAV field can be categorized by the portion of the electromagnetic spectrum they utilize:
RGB sensors
A digital RGB sensor is basically a lens and light sensor (like the camera on your cell phone) that takes photographs or videos and stores the image in a digital format on a memory card. Unlike analog film cameras, which expose chemical film strips to light, a digital camera uses a special sensor that converts light photons into pixel data and that data is used to register an image. Below is a picture of the lens, image sensor, and image processing that occurs within a digital camera using visible light (image courtesy LUCID). For more information on digital sensors please visit: https://thinklucid.com/tech-briefs/understanding-digital-image-sensors/#
Near Infrared (NIR) & Infrared (IR) image sensors
Thermal images use sensors that work quite similar to that of RGB sensors, but they detect heat or wavelength energy that is not visible to the human eye. NIR (Near-Infrared) is a part of the electromagnetic spectrum that is invisible to the naked eye (wavelengths of about 650nm to 950nm) while Infrared radiation (IR), sometimes referred to simply as infrared, is a region of the electromagnetic spectrum that is also not visible and has longer wavelengths (wavelengths of about 700 nm to 1mm). The NIR & IR response is free from color dependency. (Image courtesy of Optics for Hire)
Multi-spectral image sensors
Multispectral imagery is produced by sensors that measure reflected energy within several specific sections (also called bands) of the electromagnetic spectrum. Multispectral sensors usually have between 3 and 10 different band measurements in each pixel of the images they produce. Examples of bands in these sensors typically include visible green band, visible red band, near infrared band, etc. Hyperspectral imagery consists of much narrower bands and discrete contiguous wavelengths or “channels” within the EMS bands. A hyperspectral image could have hundreds or thousands of bands.
Jasinski, Janusz & Pietrek, Slawomir & Walczykowski, Piotr & Orych, Agata. (2010). Acquisition of spectral reflectance characteristics of land cover features based on hyperspectral images.