Automotive and Industrial RF Automotive Radar Informational

What is the difference between short range, medium range, and long range automotive radar?

Short range, medium range, and long range automotive radar differ in their operating frequency, detection range, field of view, and target ADAS applications. Short range radar (SRR) operates at 77-81 GHz with a wide field of view (typically 150 degrees azimuth) and a detection range of 0.2-30 meters, used for blind spot detection, lane change assist, cross-traffic alert, and parking assist. Medium range radar (MRR) operates at 76-77 GHz with a moderate field of view (60-90 degrees) and range of 1-100 meters, used for rear collision warning, intersection assist, and cross-traffic monitoring. Long range radar (LRR) operates at 76-77 GHz with a narrow field of view (15-30 degrees azimuth) and a detection range of 10-250+ meters, used for adaptive cruise control, forward collision warning, and autonomous emergency braking. The different range and FOV requirements drive fundamentally different antenna designs: LRR uses high-gain antennas with narrow beams for long-range detection of vehicles directly ahead, while SRR uses wide-beam antennas to detect objects across a large angular sector at close range. All three types typically use FMCW (frequency modulated continuous wave) waveforms processed with range-Doppler techniques.

Category: Automotive and Industrial RF

Updated: April 2026

Product Tie-In: Radar ICs, PCB Materials, Antennas

Automotive Radar Classification: SRR, MRR, and LRR

Modern vehicles require multiple radar sensors operating simultaneously to provide 360-degree coverage for advanced driver assistance systems (ADAS) and autonomous driving. A typical Level 2+ vehicle uses 1-2 long range radars (front), 2-4 medium range radars (corners), and 4+ short range radars (around the vehicle).

Short Range Radar (SRR)

Frequency: 77-81 GHz (4 GHz bandwidth for high range resolution)
Range: 0.2-30 m typical
FOV: +/- 75 degrees azimuth, +/- 20 degrees elevation
Range resolution: 4-5 cm (with 4 GHz bandwidth)
Applications: Blind spot detection, parking assist, door-open warning

Medium Range Radar (MRR)

Frequency: 76-77 GHz (1 GHz bandwidth)
Range: 1-100 m typical
FOV: +/- 40 degrees azimuth, +/- 15 degrees elevation
Range resolution: 15-20 cm
Applications: Side collision warning, intersection assist, rear pre-crash

Long Range Radar (LRR)

Frequency: 76-77 GHz (1 GHz bandwidth, or up to 4 GHz for enhanced modes)
Range: 10-250+ m
FOV: +/- 8-15 degrees azimuth, +/- 5 degrees elevation
Range resolution: 15-40 cm
Applications: Adaptive cruise control, forward collision warning, highway autopilot

Automotive Radar Range Parameters

Range resolution: delta_R = c / (2 x B) where B = chirp bandwidth
At 4 GHz BW: delta_R = 3e8 / (2 x 4e9) = 3.75 cm
At 1 GHz BW: delta_R = 15 cm
Maximum unambiguous range: R_max = c x T_chirp / (2 x B) x f_s/2

Common Questions

Frequently Asked Questions

Why do all automotive radars operate at 76-81 GHz?

The 76-77 GHz band is internationally allocated for automotive radar by the ITU, and the 77-81 GHz band is allocated in most countries for short range automotive radar with wider bandwidth. The mmW frequency provides compact antenna size (wavelength ~ 4 mm), good vehicle-sized target reflectivity, and moderate atmospheric attenuation for the short ranges involved.

Can a single radar perform both short range and long range functions?

Yes. Some modern automotive radars (like Continental ARS540) implement multi-mode operation, switching between wide-FOV short-range and narrow-FOV long-range modes by changing antenna beam configuration and waveform parameters within the same chirp sequence. This reduces the number of sensors required on the vehicle.

How many radars does a typical modern vehicle have?

A Level 2 ADAS vehicle typically has 1-3 radar sensors (front LRR and possibly rear MRR). A Level 2+ or Level 3 vehicle may have 5-6 radars. Level 4/5 autonomous vehicles from companies like Waymo use 6+ radars providing full 360-degree coverage with overlapping fields of view.

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