What are 4D Radars?

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- everything RF

Jan 23, 2021

4D radars are capable of creating high resolution, real-time 3D (range, azimuth and elevation) images by measuring relative position of objects in an environment instantaneously. Existing 3D radars are able to record spatial coordinates with respect to time but are not as quick to capture momentary variations of position and velocity of objects in an environment. 3D radars rely heavily on micro-Doppler features to simulate environments and objects which often lead to erroneous results or incomplete outputs.

4D radars use mmWave sensors that operate at 60-64 GHz and 76-81 GHz frequencies, to provide high resolution information about the environment. These radars use multiple-input, multiple-output antenna array systems for high-resolution mapping of its surroundings. The sensors have excellent spatial parametric response to such a degree that it can even detect normal breath movements of a person. 


4D Radar Sensor Output of a person in a room

The range, azimuth angle, elevation angle and Doppler frequency of spatial coordinates from real space are instantaneously captured and compared with point-cloud data to identify objects and respond appropriately. Doppler frequency is the change in frequency of a wave/signal when the source or object velocity change. This can be used to determine position or velocity to detect change in location/movement of objects present in an environment. 4D radars have gathered significant attention since automotive manufacturers began adopting battery-driven technology.

4D radars can be a big game changer in multiple industries. In general, it is a very empowering technology that can help understand the environment better than existing solutions. Few notable applications are:

Aerospace & Defense: To detect obstacles in the flight path, identify aircraft defects, and to map land for various defense-related purposes. 4D radars have been used by military establishments world over in naval ships and aircrafts.

Automobiles: Many car manufacturers have begun adopting 4D radar for autonomous driving.

Machine Vision: For better visibility and defect-identification in materials, in medical analysis. Machines can literally ‘see’ objects’ finer details so that necessary jobs can be performed, in less time and fewer steps. In medicine, 4D endoscopy will greatly enhance doctors to diagnose and treat patients better and faster.

Intelligent Robotics: A mojor setback in the field of robotics has been the limitations caused due to poor sensing technologies. 4D radars will herald a new area of robotics that may irrevocably change our lifestyles.

4D Terrain Mapping & disaster-prep: All kinds of terrains on Earth can be mapped to explore and study terrestrial activities. Without physically going to places to study them or without inferring too much, 4D radars could be placed on UAVs/UGVs/satellites to record spatial data of an area. They can be even used to perform penetrative analysis of rocks, sea beds or other landscapes.