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Q: What is a radar sensor?
Radar is a system that uses radio waves to detect objects. The advantages of radar include:
Reliably designed for outdoor use. Radar sensors are resistant to wind, rain, snow, fog, and sunlight. Compared to similar technologies, they are less affected by temperature fluctuations and have a wider operating temperature range.
It has a wide detection range and is flexible in installation.
It is more durable and has less downtime compared to other technologies.
Radar sensors utilize frequency-modulated continuous wave (FMCW). FMCW transmits a continuous stream of power and changes its operating frequency during measurement. FMCW measures the frequency shift between the transmitted and received signals. FMCW radar can detect both moving and stationary targets (Doppler cannot detect stationary targets).
KKIT offers two different radar frequencies: 24 GHz and 122 GHz. The 24 GHz frequency has a longer range and is less affected by ambient weather, but its accuracy is lower. The 122 GHz frequency is more accurate, can detect a wider range of targets, and is resistant to environmental and weather conditions.
Radar sensors are well-suited for applications that require vehicle detection or collision prevention when equipment is moving. For example, radar can be used for:
Vehicle inspection (including cars, trucks, and trains) for use in traffic and parking applications, toll booths, loading and unloading docks, drive-through windows, canals, and railways.
Collision avoidance in ports and manufacturing sectors (such as bridge cranes and gantry cranes)
Collision avoidance for vehicle-mounted mobile equipment (such as reach stackers, forklifts, and mining vehicles)
Collision avoidance in low-visibility factory environments (such as bridge cranes)
Level measurement in steam or dust where ultrasound cannot penetrate.
Provide reliable location feedback (e.g., ground support equipment such as reach trucks, baggage handlers, or de-icing vehicles).
The objects a radar sensor can detect depend on the sensor's operating frequency and the dielectric constant of the material. Low-frequency sensors (24 GHz) require higher dielectric constants, such as metals or large amounts of water. High-frequency sensors (122 GHz) can detect a wider range of objects, including targets made of tinted glass, wood, or other organic materials.
No, the KKIT radar sensor uses frequency modulated continuous wave (FMCW), which can detect both stationary and moving targets. Moving targets do indeed provide a stronger reflection effect compared to stationary targets.
Q: Can radar detect people, or will people nearby interfere with target detection?
Higher frequency radar sensors (122 GHz) can detect people more reliably, but they are not intended as safety devices for personnel detection. Depending on the sensor's sensitivity settings, if a person is close to the sensor and within its direct field of view, it may interfere with the detection of a intended target.
Q: What is the difference between a field-tunable radar sensor and a reflector-type radar sensor?
Adjustable-field (diffuse) radar sensors detect reflections of radio waves bouncing off objects to detect vehicles and other objects. Optimal targets include:
Large metallic objects reflect a large amount of radio waves; this characteristic is known as a large "radar cross-section".
Objects whose surfaces are perpendicular to the radar beam pattern can reflect radio signals directly back to the sensor.
Adjustable-field radar sensors can be configured with a "setpoint distance." The sensor uses the time between the transmitted pulse and the detected reflected signal to calculate the distance to the detected object, and only activates the output when the object is within the setpoint distance. Reflector-type radar sensors, on the other hand, use taught reference conditions, such as walls, floors, or special reflector targets. The sensor searches for interference in the signal returned from the reference target to detect objects between itself and the reference target.
This detection method can detect even objects with poor radar cross-sections, but they must block the signal reflection from the reference target. Therefore, reflector-type radar sensors have become the most reliable radar detection solution. The QT50R offers a separate reflector model, but any T30R sensor can be configured as a reflector-type sensor by setting the range window around the reference target.
The KKIT 24 GHz radar sensor typically has a blind zone of 0.4 meters when detecting moving targets and 1 meter when detecting stationary targets. The meaning varies depending on whether the sensor is a field-tunable model or a reflector type.
Adjustable field sensor - Although the sensor cannot reliably detect objects within the blind zone, it may still be able to detect them.
Reflector-type sensors - Reflector-type targets cannot be placed in the blind zone, but objects in the blind zone can still be detected because they interfere with the signal from the reflector target.
The detection blind zone of the 122 GHz radar sensor is 150 mm, while the blind zone of the simulated measurement is 300 mm.
Q: Can the radar sensor provide two independently set outputs?
Yes, it depends on the specific product line. Most of KKIT's radar sensors offer two zones, each with independent output.
In collision avoidance applications, two zones are typically used. For example, a longer zone is used as a "decelerate" signal, and a shorter zone is used as a "stop" signal. Two zones can also be used to determine whether an object is getting closer to or farther from the sensor.
Yes, by using two regions or analog output, radar sensors can determine the direction of an object's movement. However, it can only determine whether the object is getting closer or farther away, not whether it is moving left or right.
Yes. Both the KJT radar sensor and the T30R are available in analog models for long-distance measurements (e.g., port applications requiring crane location measurement).
Yes, radar sensors can be effectively used outdoors. Their enclosure has an IP67 protection rating, enabling reliable operation in harsh environments.
Radar sensors are resistant to extreme temperatures, snowfall, fog, heavy rain, humidity, and strong winds. They are also unaffected by sunlight. Having no moving parts, they are protected from vibrations from nearby traffic and heavy machinery. Rain covers can also be used to prevent rain and snow from accumulating on the sensor surface. If necessary, the sensors can be housed in special fiberglass enclosures (radar can penetrate certain materials). Adjusting the sensitivity or signal strength threshold can further mitigate the effects of harsh environmental conditions.
The beam pattern of each sensor is determined by its antenna and remains unchanged.
The effective beam pattern for each sensor is provided in the datasheet. If the sensor's beam pattern is too wide, consider using a narrow-beam sensor. The effective beam width varies depending on the sensor, the distance to the target, the target's radar cross-section, and the sensor's sensitivity (signal strength threshold) settings.
When installing a sensor, both the vertical and horizontal beam patterns must be considered. You may need to rotate the sensor by 90 degrees to narrow its field of view and thus ignore unwanted reflections.
Yes. Radio waves travel at the speed of light. Each radar sensor knows when it should receive radio pulses reflected from a target, and they are generally resistant to crosstalk.
The T30R can detect liquid levels in storage tanks, and it has a longer detection distance than ultrasonic sensors, allowing it to detect larger tanks.
If the output of a radar sensor jitters when the target fully enters the sensor's field of view, the radar sensor's response speed and/or sensitivity can be improved, resulting in a more consistent output.
KKIT radar sensors are certified for use in multiple countries including the United States, the United Kingdom, Europe, China, Australia, and New Zealand. Further approvals are pending. Please contact KKIT for specific requirements.
The product datasheet lists country certifications. If you cannot find your target country, please contact Keket. Due to recent FCC changes, we can now offer EU models in the US and other countries. EU models use a wider frequency bandwidth and have a shorter dead zone. For specific questions, please contact Keket.
When to use radar sensors for vehicle detection
Overview: In our vehicle inspection portfolio, we continuously research various vehicle inspection technologies, their advantages, and important considerations when implementing solutions. The ability to reliably inspect vehicles offers significant advantages in areas such as asset management, resource allocation, site security, and traffic control.
This article describes how and when radar sensors are used for vehicle detection, as well as the main advantages of this technology.
Read the first article in this series: 3 advantages of using wireless magnetometers for vehicle inspection.
