FAQs - Functions and performance

  • The presence and location of moving objects. For example, they can determine whether there are people in a room and where they are positioned.

  • The main uses are human presence detector with a range of about 10m for home security systems, white goods including room air conditioners, and so on. Other applications where the highly sensitive detection capabilities of the sensors can be put to good use include surveillance systems and gesture UI devices.

  • Because radio-wave ranging sensors operate at millimeter (or quasi-millimeter) frequency band, they are less affected by environmental factors such as temperature and weather conditions. Along with their ability to detect the location of moving objects, the sensors also benefit from high sensitivity, allowing them to detect even tiny movements such as breathing.

  • The sensors are equipped with a transmitter and antenna for transmitting radio waves, a receiving antenna and a receiver for receiving the radio waves reflected back from objects, and a signal processing unit that detects target(s) from the received signals. The sensor receives the echoes of its transmitted signal reflected back from detected objects. The signal is then processed and analyzed to extract information about whether objects are present, where they are located, and how they are moving.

  • Whereas 2D sensors are able to detect the location of objects in a two-dimensional plane, 3D sensors are able to do so in a three-dimensional space.

  • 24GHz sensors generally have lower detection accuracy, but have lower power consumption. 60GHz sensors take advantage of their wider bandwidth to provide high detection accuracy.

  • Socionext’s radio-wave ranging sensors free customers from the task of antenna design by integrating the millimeter-waveband antennas into the LSI, that requires special expertise. Similarly, the on-chip signal processing circuit included in some sensors can process the detected signals and convert them into information about whether objects are present and their range and angle. This eliminates the need for the customer to process the sensor signals.

  • The sensors mainly use FMCW, a form of linear frequency modulation.

  • The evaluation kit for 24GHz radio-wave ranging sensors is able to use the following frequency range.
    FMCW: 24.06 [GHz] to 24.24 [GHz]

    The evaluation kit for 60GHz radio-wave ranging sensors is able to use the following frequency range.
    FMCW: 57.1 [GHz] to 63.9 [GHz]
    Note, however, that the frequency bands able to be used in practice will depend on the frequency allocation rules in the country of use. Please confirm these before using the sensors.

  • Frame rate indicates the frequency of measurement. Chirp time is the time taken for each FMCW frequency sweep. It is possible to perform multiple sweeps (chirps) within one frame. Both frame rate and chirp time are configurable.

  • The theoretical resolution for distance separation when operating with a 180MHz bandwidth in the 24GHz band is around 83cm. The resolution for distance separation when operating with a 6.8GHz bandwidth in the 60GHz band is around 2cm. In practice, however, this detection accuracy can be further improved through signal processing.

  • Radio waves are able to pass through materials such as ABS, acrylic, glass, cloth, and wood, However, due to factors such as reflection at material boundaries, detection performance may vary depending on the material, material thickness, and distance between the material and sensor.

  • The sensors are less affected by environmental factors than infrared sensors. However, contaminants such as moisture or dirt may degrade detection performance by causing reflection or refraction of the millimeter-wave signal.

  • Socionext’s radio-wave ranging sensors are equipped with circuits designed for motion detection. Accordingly, completely static objects such as a vase or a sofa will not be detected when using the onboard signal processing circuit. People, on the other hand, can be detected as they continue to make tiny movements such as breathing, even when standing still.

FAQs - Other