A brief overview of RADAR technology sensors
Radar: what technology is it? How does it work? What are the advantages of using RADAR sensors?
The word RADAR, although technical, has now firmly entered everyone’s vocabulary. It is such a widely used and common word that, despite being an acronym (a name formed from the initials of other words and normally always written in capital letters), it is now even accepted in lowercase spelling!
RADAR technology: How does it work?
The acronym RADAR stands for “Radio Detection And Ranging”.
Its operation is based on a very simple principle: radio waves, at a specific frequency, are used to transmit and receive a signal. The signal is transmitted and radiated into free space: if it is intercepted by objects (targets), it is reflected back (echo) to the radar and encoded.
When processing the echo, it is first assessed whether a target signal has actually been received, after which the round-trip time of the signal is measured to determine its speed, distance, position and other data.
A bit of history
The first operating concepts were demonstrated starting in 1885, with further developments over the following years. Even our own Guglielmo Marconi spoke about it in 1922, in an address given at the Institute of Radio Engineers (now IEEE).
However, the development of a true radar apparatus is owed to important military uses during World War II, above all by the Allied Forces (primarily the British), even though the first person to develop a functioning radar system was Robert Watson-Watt in 1935 (with a radar that detected large, very distant objects, and was therefore of limited effectiveness).
A world of RADAR sensors
Like many other applications originally developed for military use, radar sensors later found application in civilian use as well. For example, modern automotive systems include radar sensors for assisted braking, anti-collision radar sensors, and radar level sensors. There are even, and they are present in CONSYSTEM’s portfolio, Radar sensors for detecting direction, motion and speed.
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RADAR frequencies
As mentioned above, the signal is transmitted at a given frequency, which can range from 230 MHz to 110 GHz. Each frequency range has a name and, above all, a specific use.
Again in CONSYSTEM’s portfolio we find radar sensors with frequencies from 10 GHz (called X band), at 24 GHz (called K band) and sensors in the 60-64 GHz band (called V band or mm – short for “millimeter”).
The signals
For the sake of completeness, the various radar sensors differ not only in signal frequency but also in the way these signals are transmitted.
Without going into lengthy, ultra-technical explanations, let’s look at the main types. It should be noted that the radar sensor for each type of application is chosen based on its operating frequency, as mentioned above, and on the signal type (even though the operating principles are the same, a radar sensor for surveillance applications will have a different frequency and signal type than a radar sensor for automotive applications, in order to provide optimal information and results for the specific application).
Let’s look at these acronyms:
CW: Continuous Wave Radar
FMCW: Frequency-Modulated Continuous Wave Radar
FSK: Frequency Shift Keying Radar
MIMO: Multiple Input Multiple Output Radar (with multiple antennas on both TX and RX and uncorrelated signals radiated simultaneously in multiple directions or in a single direction)
SIMO: Single-input-multiple-output Radar. Single input, multiple output, like the previous one except there is a single transmission and multiple receiving antennas.
What a radar sensor measures and what its applications are
A radar sensor, as already mentioned, can process various data to provide information such as target presence, motion detection, speed, distance (of the target from the sensor), direction of movement and angular position.
Thanks to the measurement information just described, the sensors can be used in numerous sectors: security applications, perimeter surveillance, area surveillance, intrusion detection, alarm systems, door openers, smart home, lighting control, home automation, touchless switches, mobile and stationary industrial applications, touchless sensors for vending machines, building automation, energy savings, escalator control, traffic, collision prevention, pre-crash alarm, intersection management, robotics, smart factory, level measurements, space measurement (radar sensors for speed detection)… Clearly, for each specific application it is advisable to use radar sensors with the frequency and signal type best suited to it, for better sensor and application efficiency.
As we can see, the possible applications are numerous, varied, and usable in many different sectors. The list presented is certainly not complete or exhaustive, as the radar sensor can also be applied in other markets and areas thanks to the various radar modules available on the market (for example, for occupancy status – the presence or absence of a vehicle in a parking space).
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Characteristics and advantages of radar sensors
Let’s look at the key features of a radar sensor, along with the resulting advantages and benefits.
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Anonymous
Detection is anonymous; no images are transmitted, allowing only outline measurement. No identification of the person or collection of personal data: strict surveillance rules (privacy compliance, etc.) are thus implemented.
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Multitarget
Monitoring and detection of a specific area tracks, distinguishes and recognizes multiple targets, not just a single one. Recognition applies to static or moving targets, people or objects.
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Multitasking
Complete information on the available targets, related to monitoring, is transmitted all at the same time (for example, speed, distance, direction, etc.).
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Weather conditions
The radar sensor works and, above all, is not affected by weather conditions; it is therefore active in heat (very high temperatures), cold (double-digit negative temperatures), sun, bad weather, rain, snow, frost, mist, and fog.
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Harsh environments
It works reliably in difficult environments, commonly called “harsh” environments, without causing problems, such as dust, pollution, dirt, foam formation, steam, humidity, pressure, noise, reverberation and vibrations.
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Indoor and outdoor use
It can be used both outdoors and indoors, as it is not affected by light or darkness (day and night).
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Maintenance-free
Since it is not affected by external influences and is insensitive to environmental conditions, once installed it does not require regular maintenance, even in complex radar systems. Note that the sensor (with its functional components) is protected by a plastic cover that does not affect its operation.
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Durable and reliable
Thanks to its operating characteristics, it is extremely robust and durable. Furthermore, since radar sensors are not exposed, are not easily visible, and are compact in size, the risk of tampering and vandalism is avoided.
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Energy efficient
Radar sensors can contribute significantly to energy efficiency, for example in smart homes or building automation, by automatically turning off lights or limiting door opening.
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Application flexibility, adaptable and versatile
Not only for the surveillance and security sector, but a solution for multiple applications (from parking sensors to anti-collision prevention), with the ability to detect different materials (liquids, bulk materials, powders). Not to mention that they are also easy to adapt to existing systems or products, or to new projects where they can be easily integrated and hidden (the radio waves of the radar sensor penetrate various plastics and are not perceptible, thus without any contact).
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Short or long distances
Radar sensors can be used for detection at short distances (less than 10 meters, for example) or long distances (over 100 meters). Even for large areas, a single radar detection system is sufficient. Finally, measurement accuracy is a strength of this technology.
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Smart technology
Radar sensors can learn through filters. During detection, it is possible to exclude a type of target, and they can distinguish targets and classify them into different categories. In this way, false alarms are excluded (for example, if animals or people enter a protected area, through the filter, in subsequent detections the animal is excluded).
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Effective
Thanks to the characteristics described above, alarms are only triggered in certain situations and, given their accuracy, the right countermeasures can be activated effectively (for example, alerting security personnel or activating cameras at the precise location of the alarm).
Other sensor technologies
There are other sensor technologies that can be used for various applications, but none of them have all the advantages (together!) of radar technology.
The most common sensors of other technologies in general are PIR (Passive InfraRed) sensors, widely used for surveillance and security, but due to their nature these sensors must be placed away from heat sources (sun, fire, etc.) and can be affected by sudden electromagnetic variations.
Furthermore, they can be visible, have limited range, limited coverage (so multiple sensors must be used in a system), require maintenance (with related costs), and do not distinguish targets – and these are not the only disadvantages of this technology.
Ultrasonic sensors are also widely used, but their most obvious peculiarity is that they have a very short detection range (up to 10 meters), are affected by weather conditions (wind, temperature variation) and also by various interferences and pressure; finally, target detection is not optimal (only for distance, not for speed and angle).
Then there are certainly laser sensors, which have some interesting properties, but are very expensive, not very versatile, larger in size than radar sensors, and the laser beam, like that of ultrasonic sensors, does not penetrate materials (the beam must not be obstructed), in addition to being dangerous for the human eye and sensitive to environmental variations. For these sensors too, target detection is not optimal (for angle and distance, not for speed).
Lots of pros. And the cons? Very few!
The question naturally arises: do radar sensors have disadvantages? What are they? Clearly there is no such thing as perfect technology, and radar sensors do have disadvantages too, but really very few!
Currently, perhaps the initial cost is a little higher than other types of sensors, but the amortization over time must then be considered (maintenance, efficiency, vandalism, etc.).
There are no other obvious disadvantages, so they offer versatility, adaptability, efficiency, intelligence and much more! What more could you want from a sensor? Perhaps a dedicated specialist to turn to with technical questions and curiosities 😀
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