Symeo develops and applies contact-free sensor technologies to provide highly reliable distance measurement, positioning and navigation in real time with no wear & tear.
Our Local Positioning Radar (LPR) uses radio signals which are not susceptible to harsh ambient conditions. We only use radio frequencies in the internationally license-free available ISM-bands.
Symeo equipment can be deployed indoor and outdoor under vibrations, extreme temperatures, dust and harsh weather conditions.
The software platform
A standard interface (TCP/IP and serial) allows quick and easy connection to any control layer.
Round trip time-of-flight distance measurement with radio signals
Radio signals are electromagnetic waves propagating at the speed of light "c" (~300.000 km/s). This speed is precisely known. With the exact measurement of the round trip travelling time "t" of signals between 2 radio stations, the distance "d" between these stations can be determinded as d=c*t.
In order to determine distances with cm accuracy, the precision for the time-of-flight measurement has to be within a few pico-seconds (0,000.000.000.001 s) only.
Radio frequencies used for LPR are within the specification of the internationally license-free ISM bands at 5.8 and 61 GHz.
The max. power output is, depending on country specific regulations, between 0.01 and 0.025 Watt - 40 times less than a wireless LAN access point or a mobile telephone.
With a precise distance reading between a moving object and at least 3 fixed reference marks at known position, the dynamic position of this object can be determined.
In the following, the fixed devices will be referred to as transponders (TP) and the moving unit is called base station (BS). With 2 antennas connected to the BS, the BS can compute both antenna positions independently in order to not only measure the position, but also the orientation (the angle σ) of the object in the chosen coordinates system.
Fixed TPs at known positions are used as reference marks for the positioning of a free ranging BS. The BS broadcasts a radio signal that is received, processed and echoed back to the BS by each TP without time delay. The echo is coded with the respective TP identification in order to allow the BS to separate each TP´s answer. Thus, the BS can determine the round trip time-of-flight and the current distance to every TP independently. With at least 3 TPs within range, the BS position is well-defined.
LPR-B devices can either be configured to act as TP or as BS. All units have their own ID-number, through which they can selectively communicate peer-to-peer with neighbouring devices. In order to measure distances between devices, a pico-seconds precise time synchronization must be effective to determine the time-of-flight of signals sent.
Communication between the devices takes place in the same ISM band that is also used for the distance measurement. Distance readings and other sensor data can be sent within the LPR-B network to any device within radio range. The position of moving objects can therefore be provided on-board the object or at a remote location without the need for wireless LAN access.
Reliable and robust design for industrial applications
LPR measurement is not affected by ambient conditions like dust, dirt, steam, rain, snow, vibration or extreme temperatures. The devices are designed for indoor and outdoor applications.