Driver assistance
Driver assistance

24 GHz radar

  • A pioneer in the field of 24 GHz automotive radars for rear applications; first company with rear applications on the market
  • More than 17 years of experience in radar development and production. Over 30 million sensors manufactured on 24 GHz basis (as at: January 2020)
  • As the global regulatory standard, 24 GHz radars in the ISM band/200 MHz are crucial to international business

The figure shows one of the radar sensors for rear applications with a partial view of the covering radome, the planar patch array antenna and the printed circuit board with the controller and power supply.

The overall system consists of two sensors, mounted at the vehicle’s rear, with a sensor-to-sensor communication interface, and is capable of handling up to five applications. The sensors are hidden behind the bumper.


  • 24 GHz radar

HELLA 24 GHz radar sensors allow vehicle manufacturers to offer their customers driver assistance systems in all automotive segments, even in the compact class.
The 24 GHz narrowband technology has near world-wide homologation, making it a perfect fit for global platforms.

Blind spot monitoring

  • This function monitors the area in the driver’s blind spot and warns him or her of danger when changing lanes.
  • The sensor operates in the near range.
  • This function is currently in series production at a number of OEMs.

Lane change assistant

  • The lane change assistant makes driving safer by warning if a lane change is a dangerous maneuver.
  • A warning distance of 70 meters gives the driver enough time to abort the lane change. This function ensures maximum safety when driving on highways.
  • It is currently in series production at several OEMs.

Rear pre-crash system

  • The rear pre-crash system tracks vehicles approaching from behind and, in the event of an imminent collision, pre-activates safety devices such as airbags, seat belts etc. The system is currently in mass production.

Rear cross traffic alert

  • The rear cross traffic alert warns the driver of approaching vehicles when maneuvering out of a parking space.
  • The function is activated by selecting reverse gear and is based on the radar sensor’s side detection capability.
  • Rear cross traffic alert is in production development.

Vehicle exit assistant function

  • The vehicle exit assistant monitors the area to the right and left of the car doors; both on the passenger's and the driver's side to the back and to the front.
  • The function warns the occupants if the car door cannot be opened safely.

Further technology considerations for selection of the 24 GHz frequency are:

  • Low-cost MMIC technology is available for the 24 GHz frequency band
  • Small size allows easier integration in the bumper
  • Frequency modulation is ideally harmonized with the antenna size
  • Excellent transmission properties of 24 GHz technology allow the sensors to be hidden behind bumpers
  • Mature mass production of products, functions and installation
  • Ideal value for money compared to other radar technologies

24 GHz radar
Measuring principle LFMSK
Frequency range 24.15 GHz/ISM
Bandwidth <= 200 MHz/ISM
Transmission efficiency <= +20 dBm peak, EIRP
Cycle time 50 ms
Sensing area  0.75 m to 70 m
- Separability 1.5 m with 200 MHz OBW
Speed measurement  
- Relative speed interval -70 m/s to +70 m/s
- Separability 0.32 m/s
Sensing area azimuth 165°


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HELLA Radar Blindspot

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HELLA Radar Exit Assistant Function

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HELLA Radar Lane Change Assistant

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HELLA Radar Rear Cross Traffic Alert

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HELLA Radar Rear PreCrash
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