What Is a Corner Radar?

A corner radar is a type of radar that typically has a wide field of view and high resolution. In the past, such devices were also called “short-range radar,” but their performance and cost have improved, unlocking expanded use cases in automotive and beyond.

Today, corner radars are typically mounted on the corners of vehicles to detect nearby objects and inform ADAS. They can be placed on just the rear corners, just the front corners or on all four corners of a vehicle, depending on the functions and level of automation required. They help in multiple applications, including lane-change and cross-traffic assistance, blind-spot detection, collision avoidance, pedestrian detection, and proximity warnings.

Corner radar evolution

Radars were first used in automotive applications in the 1990s, primarily for adaptive cruise control (ACC). Radar systems initially used a forward-facing radar to monitor for vehicles ahead and maintain a safe following distance. As ADAS evolved for more complex capabilities beyond cruise control, sensors that could cover vehicles’ side and rear zones were needed.

Early corner radars were developed using 24 GHz technology and were primarily designed to support blind-spot detection and rear cross-traffic features. As ADAS capabilities expanded and operational design domain requirements increased, higher performance was needed.

From the start, Aptiv has exclusively delivered 76 GHz corner radars, which offer higher resolution and a more compact form than alternatives — employing the same sensor architectures used in forward-facing radars. Over time, 76 GHz has become the industry standard for corner radars. In 2017, Aptiv received an Automotive News PACE Award for 76 GHz Short-Range Radar for 360-Degree Sensing, an advancement that represented an inflection point where corner radars evolved from simple awareness sensors to integral components in modern ADAS.

Cameras help with object detection and classification, but their performance is limited in poor weather or low light. Radar offers all-weather reliability and precise speed and distance measurement. Often, cameras and radars are used together through sensor fusion to capitalize on the advantages of both sensing modalities.

Aptiv has been a pioneer in this space for more than 25 years. We introduced the industry’s first radar-based ACC system in 1999, followed by innovations such as radar-based backup aids and solid-state radar. Today, Aptiv® SRR8+ builds on this experience, delivering high-resolution sensing and advanced object classification for next-generation ADAS.

Advantages of corner radars

Corner radars detect vehicles, pedestrians and obstacles in blind spots and cross-traffic zones in real time. They are especially critical for urban driving scenarios and enable safety features that reduce collision risks when a vehicle is changing lanes, reversing or parking. Unlike cameras, corner radars work in rain, fog, snow and darkness without performance degradation, which ensures consistent safety in various conditions.

Like all radars, corner radars use the Doppler effect to instantaneously measure the speed of moving objects. The Doppler effect occurs when the frequency of waves reflecting from an object changes as the object moves toward or away from an observer — in this case, the radar antenna. To determine distance, radars use time-of-flight measurements based on frequency-modulated continuous-wave radar techniques.

These capabilities make corner radars more reliable than cameras alone, given that cameras cannot easily calculate velocity without complex stereo setups.

Compared with forward-facing radars, which focus on long-range detection for adaptive cruise control and highway driving, corner radars provide a shorter-range, wide-angle view. Each corner radar provides a horizontal field of view of up to approximately 150 degrees, enabling strong coverage of blind spots and cross-traffic zones — areas that forward-facing sensors cannot monitor effectively.

Recent research has explored vehicle architectures that use two front corner radars combined with sensor fusion to expand forward coverage and enhance object detection in complex driving scenarios. Eliminating the forward-facing radar could reduce hardware costs, weight and packaging complexity while improving safety performance. While the research shows promise, forward-facing radars remain a core part of many ADAS architectures today.  

An effective corner radar should have several key characteristics:

• High resolution and angular accuracy for precise object classification

• A wide field of view to minimize blind spots

• Fast refresh rates for real-time detection in various environments

• Strong performance in all conditions, including rain, fog and snow

• A compact design for seamless integration into vehicle corners, without compromising aesthetics or aerodynamics
  

Latest advancements: Aptiv® Gen 8 SRR8+ Corner Radar

Aptiv® SRR8+ is a major leap forward in radar technology. The SRR8+ features Aptiv’s widest field of view to date, enabling better performance in close-range safety applications.

This expanded field of view supports precise detection of nearby objects during low-speed maneuvers, such as parking. The SRR8+ also incorporates ultra-wideband technology, which enables accurate short-range localization.

The SRR8+ includes improved range and resolution, enhanced object detection, and classification capabilities to support next-generation ADAS and semi-autonomous driving. The SRR8+ is also smaller than previous-generation radars, making it easier to integrate into vehicle designs while still maintaining strong performance.

Corner radars will continue to be an important part of perception systems for the foreseeable future as vehicles become more autonomous and require robust and diverse sensing modalities to operate with confidence and at speed.