Using radar sensors in security applications: benefits and technical deployment

For surveillance tasks in the safety and security field, radar sensors are often essential instruments.

The benefits of radars are evident: radar is capable of detecting motion, measuring speed, distance and the angle of arrival as well as the direction of movement.

Radar can work in adverse conditions like rain, fog and dust and is able to cover long range as well as close distance. It preserves anonymity due to the fact, that it is not able to deliver high-resolution pictures from faces or license plates, which ensures its acceptance.

Motion sensors for anti-burglary protection systems – indoor or outdoor – are very inexpensive components, which take advantage of the doppler effect. In this application, radar replaces more and more the Passive Infrared Sensors, which have established in the past because of their low price.

Reliable

Radar, however, is much more reliable, because it is not affected by thermal variations and it offers additional information like direction of movement and the actual speed, making detection safer and more robust.

InnoSenT offers an innovative solution with the SMR series. SMR stands for surface-mountable radar and describes a tiny, 15mm x 20mm x 3mm, Radar frontend, which is delivered on tape and reel and which can automatically be pick-and-placed and soldered to the customer’s PCB in a standard SMT process.

This ultra-small device incorporates a complete 24GHz transceiver including a low noise amplifier. Persons can be safely detected in a distance of up to 15m. It consumes only 45mA from a 3.3V voltage source. For power sensitive applications e.g. in battery powered systems the power consumption can be drastically reduced by operating the sensor in a pulsed mode.

Using a duty cycle of 1:1000 or even less it is possible to reduce the average operating current to a few microamps. Three different antenna variants are available to cover a field of view ranging from 40 to 120 degrees.

In case distance information is also necessary, the SMR can be supplied optionally as a VCO-transceiver, which can be frequency-modulated by applying an analog modulation signal to the VCO input.

A frequency divider output, switchable between two different division ratios, gives the opportunity to read back the frequency or to operate the device in a phase locked loop.

SMR: The surface-mountable radar

For far range area surveillance the ISYS-3106 is a perfect choice. It is a full digital FSK- radar, which detects moving objects with a radial speed component of 0.25km/h up to 140km/h.

The Frequency-Shift-Keying-modulation suppresses unwanted clutter from stationary objects very effectively. A person is visible in up to 300m distance. The field of view (half power beamwidth) is 15 degrees in azimuth and 10 degrees in elevation.

Broader view

If a broader view is required, two sensors can be combined in a Master-Slave configuration. An object list as well as tracks of detected targets with range, speed and angle information is accessible via Ethernet interface.

Due to the sensor´s architecture, multiple objects can be captured, and they can be separated as long as they differ in speed or range.

ISYS-3106: coverage of two sensors in master-slave configuration

Real 3D-resolution (in range, speed and angle) can be achieved with MIMO-architectures, which have multiple inputs and multiple outputs. The ISYS-5010 is an example for a sophisticated MIMO-radar, which uses 4 receivers and 2 transmitters to generate 8 virtual antennas with an angular resolution of 16 degrees in azimuth. Two additional transmitters are used to extract the angle information in elevation.

ISYS-5010: separation of objects in range, speed and angle

The radar employs two-stage LNAs for each receive channel for lowest noise performance. The distance and speed information are gained from a 2D-Fast-Chirp-FMCW modulation (frequency modulated continuous wave) capturing also non-moving objects in up to 55m distance. The sensor provides a target list on SPI and it can be configured via UART with the help of a supplied Graphical Users Interface.

Many security applications can be covered with InnoSenT’s standard product portfolio. On demand, customised developments will also meet exceptional challenges.

Check out the latest radar sensors from InnoSenT at IFSEC International, 20-22 June 2017, London ExCeL. You can find InnoSenT on stand F1180. 

Listen to the IFSEC Insider podcast!

Each month, the IFSEC Insider (formerly IFSEC Global) Security in Focus podcast brings you conversations with leading figures in the physical security industry. Covering everything from risk management principles and building a security culture, to the key trends ahead in tech and initiatives on diversity and inclusivity, the podcast keeps security professionals up to date with the latest hot topics in the sector.

Available online, and on Spotify, Apple Podcasts and Google Podcasts, tune in for an easy way to remain up to date on the issues affecting your role.

Listen to the podcast today