The LPM (local position measurement) technology is a system with which the position of a freely mobile object can be determined within a local bounded three-dimensional area. As the fundamental principle the measurement of the run time of an electromagnetic wave is used.
The system can be installed indoors as well as outdoors and is not based on GPS (global positioning system) technology, with the consequence that the computation of the position is not done by the object but by a central control unit. That means the user is able to refer to any object and receive its specific position in real time.
The LPM system consists of numerous base stations, with the number depending on the area that has to be covered. The base stations are connected by a fibre optical network with a central master processing unit, where position evaluation and final object tracking is done.
Every object that should be tracked by the system needs to carry a so-called transponder. This is a device (the size of a credit card in its first edition) with a weight of approximately 0,1 pound, depending on the used power supply. A battery serves as power supply and a controller controls base-band measurement electronics as well as the communications unit. The frequency of operations lies within the 5-GHz ISM-band. Transponders can communicate with the base stations, both for additional data exchange and for receiving activation commands. In the RF-part a highly linearised oscillator generates very fast chirps for measurement purposes. Together with a reference transponder with a well-known absolute position the position of each individual and activated transponder can be determined from measurements of chirp-responses at receivers of at least 4 base stations.
LPM is already applied in various fields like driver training centres, sports science institutes, logistics institutes, air races, research stations for animal behaviour etc.
Measurements are carried out both outdoor and indoor with strong multi-path reflections. The measured accuracy of 3D positions is better than 10 cm. Every cell covers an area of 500x500m. Up to 30 cells can be combined to cover a much greater area.

Innovative Aspects:
Currently there is no comparable technology available offering the following features:" Accuracy: < +/- 10 cm " Sampling rate: 1 kHz" Number of objects: 16.384 (14-bit)" Telemetry: 32-bit data channel" Dimensions: 4, 3D + speed vector" Carrier: 5,8 GHz " Area: 500 x 500m (= 1 cell, cascading of 30 cells possible)

The existing global positioning system (GPS) often cannot fulfil speed and accuracy requirements, and can only be used outdoors.
The radio frequency identification system (RFID) can only be used indoors, has a very small range, and it is not possible to measure the object's position.
The fast and highly accurate measurement of local positions and velocities of moving objects is of great interest for industrial applications but also for sports and other application fields. With up to 1000 measurements per second the presented novel local position measurement system is able to track the motion of numerous targets in real time and with high accuracy.

 

Patents/Rights: Patent(s) granted

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