Typical UAV Architecture

Power Systems Module (PSM) provides power for both the payloads, the motors and flight control components. It also includes a backup battery system for increased reliability and endurance of the UAV. ​

Communications and Surveillance Module includes UL operating for receiving flight commands, telemetry radio modem, Camera and Digital Video transmitter, and Pan & Tilt mechanisms for controlling the on-board camera. ​

Navigation Module, includes autopilot, compass, GNSS receiver, altitude meters and air data computer (ADC) ​

Flight Control Module includes Rudder, Elevators, Aileron and Throttle, all controlled by Servo Board, which itself is controlled by Autopilot. 

Drone Components

Fuel Cells and Batteries

  • Like all other drone components, fuel cells and batteries must provide maximum power while having minim possible weight. ​
  • Most of the existing UAVs use electrical batteries as the main source of energy. The preferred choice of UAV manufacturers is Lithium Polymer (LiPo) batteries due to their high energy density for a given weight, compared to other types of batteries. ​
  • A LiPo battery is constructed from individual cells, where each cell consists of some metal and chemicals packaged together to generate an electrical charge. By connecting these cells together in various ways it is possible to make different LiPo batteries with various voltages, and capacities.

Motors and Props

  • There are a few types of motors that are use to build drones. These must be light and powerful motors to enable floating in the air.​
  • The cheap, lightweight, small, and powerful motors used in the majority of drones are Brushless DC motors (BLDC). ​
  • For small drones, BLDC motors are not suitable, but instead they use small DC gear motors.

UAV Propulsion System

  • As the endurance of the drones is one of the key parameters, the search for new, more efficient energy sources is constantly underway. ​
  • Recently introduced UAV propulsion systems based on fuel cell have attracted significant attention in recent years due to their potential to dramatically improve the efficiency of the UAV applications​
  • In this example, energy is generated by hydrogen with a hydrogen tank selected as the storage facility. The mechanical energy converter is implemented as the combination of a fuel cell and electric motor, while a propeller represents the lift/thrust converter.  ​

Navigation Systems

  • UAV navigation – consists of on-board modules (altitude meter and autopilot) and ground control module. Effective operation of these modules rellies on GPS or potentially any other satellite navigation system (e.g. GLONASS or GALILEO). This is very similar to in-car navigation systems ​
  • GPS based navigation – is related to the concept of triangulation to determine a position on the ground. Triangulation is  process where the location of a radio receiver can be determined by measuring the radial distance of the received signal from different sources.

Control Channel for UAVs

  • Long range UAVs are usually controlled via satellite or cellular links
  • The EU harmonised decision 2013/752/EU for Short Range Devices (SRD) defines model control as: “a specific kind of telecommand and telemetry radio equipment that is used to remotely control the movement of models (principally miniature representations of vehicles) in the air, on land or over or under the water surface.” There are two types of radio controlled models: those that operate primarily on the ground or on water, known as “surface” models; and those that are airborne. 
  • Different countries have different regulations
  • European reserved VHF & UHF frequency bands 
        • 35 MHz: aircraft only.
        • 40 MHz: surface vehicles or aircraft.
        • 27 MHz: general use, toys, citizens band radio.
        • 2.4 GHz 13-cm UHF band spread spectrum: surface vehicles, boats and aircraft.
        • Within the 35 MHz range, there are designated A and B bands. Some European countries allow use only in the A band, whereas others allow use in both bands. 
  • United Kingdom reserved frequency bands 
      • 458.5-459.5 MHz: low-UHF band for surface vehicles or aircraf

On Board Sensors

  • 3  Types:​
    • Essential for flying with GPS​
      • GPS receiver​
      • GPS antenna​
    • Essential for providing services​
      • Cameras (both optical and thermal)​
      • Gimbal for stabilization​
      • Accelerometer​
      • Gyroscope​
      • Sensors for CBRNE detection​
    • Essential for flying with no GPS navigation
      • INS​
      • Cameras for visual navigation 3D terrain imagery

Video and Data Downlink

  • On small professional UAVs these are COFDM downlink operating in 1.3 GHz frequency band
  • On recreational UAVs these are 5.8 GHz WiFi data link
  • On long range UAVs these are satellite links
  • Recently, 5G cellular links were proposed
  • COFDM Video and data downlinlink provided by Rinicom

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