RADAR

Radio Detection and Ranging (RADAR) has multiple uses in a variety of fields. The primary objective of RADAR is to detect targets of interest and derive information such as range, angular coordinates, velocity and reflectivity signature (“Princ. Mod. Radar,” 1987).

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Working Principles

A RADAR transmits Electromagnetic (EM) energy, generated within a transmitter unit, through antenna (serving as a transducer to couple EM energy into the atmosphere) toward a region of interest (through concentration of the propagating EM wave toward a specific direction) at the speed of light (“Princ. Mod. Radar,” 1987; Richards, Scheer, & Holm, 2010). A detection is identified when an object intercepts the propagating energy, causing a scatter, or polarisation, of the energy in various directions. In general, some of this intercepted energy is reflected back towards the original source. Due to the time delay through this process (transmission, reflection and reception of energy), and the speed of energy propagation (speed of light) the range to the reflective surface can be determined (“Princ. Mod. Radar,” 1987; Richards et al., 2010).

There can be potential interference in the form of: (a) internal and external electric noise; (b) reflected EM waves from other irrelevant sources – known as clutter; (c) unintentional EM waves from the environment, referred to as EM Interference (EMI); and (d) intentional jamming from electronic countermeasures (Richards et al., 2010). Therefore, the RADAR performance under EM interference needs to be considered. Furthermore, RADAR performance can be influenced by numerous factors, including: propagation frequency, altitude, and humidity (i.e. rain, fog and clouds). Making an informed choice of EM wave frequency lessens this effect resulting in “all weather capable” RADAR (Richards et al., 2010).

Application to Proximity Detection

The independent, stand-alone nature of a RADAR sensor is a notable advantage; there is no strict requirement that other objects/vehicles must have a similar system equipped in order for a single system to determine range and velocity information. This being said, further development could be considered when implementing RADAR towards a Proximity Detection System (PDS). This may include sensor fusion techniques for improved performance using other sensor modalities or establishing communication between separate PDS (mounted on the Local Object (LO) and the Remote Object (RO)) to share information towards a better understanding of the environment. Furthermore, multiple RADAR sensors (per PDS unit) may also be required given that RADAR must be mechanically and electrically designed (i.e. designed to rotate) to cover a larger detection region.

Advantages

  • No additional infrastructure is required onto remote object(s)
  • It is a mature technology in various industries, in particular: the automotive sector

Limitations

  • In some cases, additional software may be required for detection, classification and tracking processes
  • Potentially subject to blind spots around the equipped machine
  • Subject to the Multipath Effect, a phenomenon whereby signals arrive by two or more paths.
  • RADAR performance may be affected by harsh weather conditions and may require maintenance to clear dirt and debris from the sensor
  • Limited Field-of-View (FOV)
  • Difficult to develop a physics-based sensor model for simulation-based testing