.psd/jcr:content/renditions/cq5dam.thumbnail.319.319.png)
10 Things You Should Know about Radar
Table of Contents
Radar sensors ensure appropriate fill levels in a hopper are maintained to keep production moving. When materials such as grain or concrete mix are loaded into a hopper, dry and dusty particles fill the air. Dust will cause many optical sensors to suffer signal loss, while ultrasonic devices may give incorrect readings if debris builds up on the sensor. Radar waves, on the other hand, pass through the airborne particles to accurately measure the hopper levels.
Someone working a drive-thru window at a restaurant, bank, or pharmacy needs to respond quickly when a customer arrives. A K50R radar sensor can detect cars in snow, rain, fog, or sunlight—conditions that may cause false or no detection when using other sensing technologies. Quick and efficient vehicle recognition lets businesses analyze traffic patterns and eliminate bottlenecks, minimizing wait times and ensuring timely service.
Extreme temperature swings, fog, steam, and water spray inside an automated car wash can make detecting a vehicle’s position problematic, even by commonly used ultrasonic sensors. Temperature variations can affect the speed of ultrasonic sound waves, which may result in false vehicle location information. Noise from equipment and changing air currents inside a wash may also interfere with ultrasonic sensors’ ability to accurately detect the edges of a vehicle. However, a single T30RW radar sensor configured for retroreflective mode can reliably determine a vehicle’s position, telling the wash system to turn each section on and off at the correct times. This makes the process more efficient by saving water and cleaning agents, prevents equipment from contacting and damaging vehicles, and ensures a high-quality wash.
Each day there are more than 100,000 commercial flights worldwide. These require a great number of ground support vehicles like belt loaders, passenger boarding steps, and catering trucks. This constant traffic on the tarmac greatly increases the potential for accidents and damage to aircraft.
New standards require certain ground support vehicles to include collision-prevention sensors. Instead of a narrow beam pattern, they can employ a radar sensor with a wider beam, like the 120- x 40-degree beam found in the Q90R2, to safely approach aircraft on the tarmac. The sensor constantly monitors the distance between a vehicle and the aircraft and sends that information to the vehicle’s controller. If the vehicle gets too close to a plane, the vehicle’s controller automatically slows the vehicle to avoid running into it, preventing a collision that costs both money and time.
In an automotive assembly plant, the leading edges of car bodies need to be detected so they can be correctly positioned in a paint tunnel. The surface may be unpainted, matte, or glossy, so they can be difficult for optical sensors to accurately recognize because the shiny, angled surface can reflect light away from the sensor’s receiver.
Radar sensors, such as Banner’s T30R series, can identify objects that have uneven surfaces; are glossy, reflective, matte black, or any other color; or have mirrors or windows. This allows the T30R radar sensor to reliably detect the position of each body on the line, then send this location information to the robotic arms’ controllers so they know where to find each part.
By detecting any objects on the assembly line regardless of color, shape, or reflectivity, production can continue with less downtime.
Large gantry cranes moving heavy loads through outdoor shipping yards often work in close proximity to one another. A collision could result in damage to cargo, expensive crane repairs, and halted cargo movement. Long-range radar sensors with a narrow beam pattern, such as the Q240R, or the Q90R2 with its highly-configurable multidimensional sensing ability, can reliably detect obstacles and other cranes before a collision occurs while ignoring nearby cargo containers.
Warehouse lifting equipment, like reach stackers and forklifts, can collide with and damage shipping containers. These collisions result in lost time, damaged goods, and broken equipment. Q90R and K50R sensors can be used for shorter-range collision-avoidance protection. When mounted on lifting equipment, these sensors detect the shipping containers and send a signal to the equipment to automatically slow down and approach at a safe speed.
Because radar is not susceptible to changing environmental conditions, sensors can even be used to monitor equipment that operates both indoors and out, such as lifts transporting cargo from indoor loading bays to vehicles waiting outside. Using the same sensors across all equipment also minimizes maintenance costs.
Some radar sensors operate at a lower frequency, such as the QT50R which emits waves at 24 GHz. Others use a higher frequency, including the T30R which operates at 122 GHz. Then there are those, like the K50R, which operate somewhere in the middle at 60 GHz. Whether low, high, or in between, each of these frequencies has their benefits.
Most useful for detecting large objects that are far away, a lower-frequency 24 GHz sensor produces long wavelengths. Long-range detection and an ability to ignore ambient weather like heavy rain or snow make it the most effective outdoor sensing solution. Conversely, a higher-frequency 60 GHz or 122 GHz sensor produces shorter waves which can detect smaller objects, deliver superior accuracy, and are able to sense a wider range of dielectric materials.
When photoelectric or ultrasonic sensors are positioned close to each other, signals from one can interfere with the other, causing inaccurate sensing data, diminished performance, and reduced sensor reliability.
Industrial radar sensor technology, on the other hand, is designed to avoid cross talk. Radar sensors use a range of different frequencies, avoiding interference from other devices operating at similar frequencies or from other sources of electromagnetic radiation.
Sophisticated signal processing algorithms also help radar avoid cross talk by distinguishing between radar returns and filtering out unwanted signals, extracting only the relevant information. Additionally, synchronization and time division techniques are used to ensure radar systems operate in a coordinated manner, carefully scheduling transmission and reception times to avoid transmitting and receiving simultaneously.
Monitoring liquid levels in tanks has often required a sensor mounted inside the tank. However, sometimes an external sensor solution is preferred, especially if direct contact with the liquid could damage or adversely affect the sensor. With their ability to penetrate most plastic and glass, radar sensors can be installed outside tanks where they are easier to mount and maintain.
A T30R radar sensor can be installed on a plastic tank’s outer wall or a metal tank’s sight glass. The sight glass or tank may be dusty or dirty, the plastic may be opaque, or the material inside the tank may be shrouded in mist. Even if the liquid has an uneven surface or is stored under pressure or in a vacuum, the high-frequency microwaves pass through the plastic or glass to measure the liquid level inside. When connected to an illuminated indication system, personnel can be visually alerted to the tank’s fluid level.
To recognize vehicles entering an auto repair bay, K50R radar sensors can be mounted under heavy-duty plastic, flush-mounted with the driving surface. The radar waves penetrate dirt and debris left behind by vehicles on the repair bay’s floor and detect cars as they pull in. As part of an indication system, these sensors can let employees know a customer has arrived so they can quickly greet the customer, minimizing wait times and improving check-in efficiency.
There are certain situations in which sensors monitoring a large area must recognize only certain objects while ignoring others, such as disregarding objects in the background or smaller items near the sensor.
A truck approaching a loading dock can be detected by a K50R-4030 wide beam sensor. By instructing the sensor to recognize the nearest target, it detects the truck parts closest to the dock instead of an axle or truck body that might return a stronger signal. Banner strip lights connected to the sensor can give real-time visual feedback to the driver so they know exactly how close the truck is to the dock.
Using Banner’s radar configuration software, the detection distances of the K50R can be set so the sensor only looks within a predetermined range. Vehicles driving in the background, posts close to the dock, and other unwanted objects both near and far will be ignored.
A busy rail yard is a large-scale dynamic work environment with numerous operations occurring simultaneously. Vehicles and rail cars of different shapes and sizes, moving at varying speeds on and around multiple tracks, and carrying myriad types of materials present a serious object detection challenge.
Trains consist of locomotives and a wide assortment of rolling stock including boxcars, flatbeds, hoppers, tankers, and more. Being able to track numerous trains and types of cargo on trailers at different distances, even while they are moving, can be handled by a radar sensor like the Q130R. The ability to detect both moving and stationary targets makes FMCW radar a more reliable solution than Doppler radar, which is only able to detect moving targets.
Despite dust swirling around the yard or dirt building up on the Q130R sensor, the radar signal can still detect objects up to 40 meters away. The radar sensor can be set to ignore trains parked in the background on one track while recognizing other trains as they pass in front, triggering RFID antennas so operators know the precise locations of cargo in the yard. The long-range detection afforded by radar sensors, plus radar’s ability to ignore ambient weather conditions and airborne dust and dirt, make it an ideal rail yard solution.
Sharp edges and flat surfaces mounted at an angle can act like mirrors, deflecting radar signals and preventing a radar system from receiving accurate information. To ensure reliable object detection, a radar sensor with a wide beam angle can monitor large areas and better recognize rounded surfaces and angled objects.
A busy surface mine has equipment of all shapes and sizes, both mobile and stationary. Powerful haul trucks transport both mined and waste material, and their enormous size creates numerous blind spots all around the vehicle. With little room for error, collision avoidance is key to an efficient operation. The outdoor environment also presents other sensing challenges, including wind, rain, and snow, plus dirt and dust churned up by mining operations.
Wide-beam radar sensors like the Q130R and QT50R can be deployed on the front and rear of haul trucks as a primary component in collision avoidance systems. Not only do they ignore ambient weather conditions, sensors can be configured to detect objects in blind spots regardless of the object’s shape, size, color, material, or surface finish. By connecting a Q130R or QT50R to LED indicator lights, the truck’s operator can quickly see when to check blind spots and slow down or stop the equipment, reducing the chance of a potentially costly collision.
Radar Is the Reliable, Environment-Resistant, All-Around Automation Sensing Solution
On their own, radar sensors are a durable and reliable method for object and vehicle detection, collision avoidance, positioning feedback, and more. They can do all of this either indoors or out, at short ranges or long distances, even when the environment presents unusual challenges that might trip up other sensor technology. But when incorporated as part of an automated system comprising sensing, real-time indication, and instant feedback, radar becomes an incredibly powerful—and necessary—component of a safe and efficient operation.
For more information about radar sensors, please visit our Radar Sensors Page.
Glossary
Beam pattern: The way a transmitted radar signal is concentrated. A narrow beam pattern focuses on a smaller area, allowing more precise object detection. A wide beam pattern reaches a larger area to better detect irregular surfaces and targets at angles.
Dead zone: An area near the transmitter in which a radar cannot detect or measure a target.
Dielectric constant: The measure of an object’s ability to develop an electrical field and store energy. High-dielectric materials, such as metal and water, are more electrically conductive and reflect radar signals better than wave-absorbing materials like plastic, wood, cloth, and other organics.
Frequency Modulated Continuous Wave (FMCW) radar: Sends a continuous signal from a transmitter and receiver and compares the transmitted and received frequencies. FMCW can reliably measure the distance of the target from the radar system.
ISM bands: 24 GHz, 60 GHz, and 122 GHz are frequencies of the radio spectrum set aside for use by Industrial, Scientific, and Medical purposes. The frequencies at which industrial radar sensors operate fall within these designated ISM bands.
Pulsed Coherent Radar (PCR): Sends a series of pulses toward the target instead of a continuous wave. The PCR sends a pulse, turns the transmitter off, receives echoes from the target, then turns the transmitter back on to send a new pulse and continue the cycle.
Radar Cross Section (RCS): A measure of a target’s ability to reflect electromagnetic signals back toward the receiver. The greater an object’s RCS, the easier it is to detect. While the target’s size is one factor, the material, shape, orientation, direction of travel, and angle at which radar waves reflect off the target also affect the RCS.