Radar vs LiDAR vs Camera vs UWB: CAV Sensors

Introduction : Autonomous vehicles do not reply on data from single sensor, instead they rely on sensor fusion which combines data from multiple distinct technologies to create picture of the road. While Cameras, Radar, and LiDAR map the physical world, Ultra-Wideband (UWB) is emerging as the critical link for communication and cooperative safety. Before we explore differences between them, let us understand how each sensor functions and the specific role it plays in the ecosystem.

Cameras (Optical Sensors)

Cameras are the only sensors that can “read” the world in color and high resolution, similar to the human eye. They are mainly used for object classification. They are essential for reading speed limit signs, detecting brake lights (red vs. green) and seeing lane markings.

Limitation:

• Like human eyes, they are easily blinded. Direct sunlight, heavy rain, fog, or darkness significantly degrade performance.
• They require massive computing power (AI) to interpret a 2D image into 3D data.

Radar (Radio Detection and Ranging)

Radar uses radio waves (typically in the mmWave spectrum) to bounce signals off objects. It determines speed and distance of other vehicles. It is the standard for Adaptive Cruise Control (ACC) because it can instantly measure velocity using the Doppler effect.

Advantages: It is impervious to weather, working perfectly in fog or snow where cameras fail. Limitations: It lacks resolution. it is difficult to differentiate between a motorcycle or a loose tire.

LiDAR (Light Detection and Ranging)

LiDAR transmits laser pulses per second continuously to build precise 3D point cloud of the environment. With precision mapping, It tells the car exactly how far away every edge of a building or curb is with centimeter level accuracy.

Limitations:

• While prices are dropping, LiDAR systems are expensive and mechanical versions can be fragile.
• They can also be confused by heavy rain or snow reflecting the laser beams.

UWB (Ultra-Wideband)

UWB is the newest addition to the suite. Unlike the others, which are passive (looking at the world), UWB is active and cooperative. It allows the car to “talk” to other cars (V2V) or pedestrians’ phones (V2P). It measures the Time of Flight of signals to determine the exact distance and relative position of other actors in the environment.

Advantages:

• It prevents spoofing such as hackers faking GPS signal or relay attack to unlock car etc.
• It processes data much faster than cameras, allowing cars to react instantly in “platoons” (i.e. driving close together at high speed).

Comparison between Camera Vs. Radar Vs. LiDAR Vs. UWB

Summary:

UWB acts as the verifier, ensuring that the data coming from the other sensors is accurate and that the vehicle isn’t reacting to a spoofed signal. It bridges the gap between seeing a hazard and communicating with it.