Process and system for calculating distances between wireless nodes

Kurzfassung

A research centre based in Barcelona (Spain) has developed a novel procedure to calculate distances between wireless nodes for further positioning, without hardware customization required. This procedure and the system associated calculate the location easily by means of any WiFi technology (e.g. IEEE 802.11). Partners to further develop the system and/or to establish commercial agreements with technical cooperation are sought.

Details

Location techniques based on multilateration imply measuring the distance between the target node and several landmarks, which position is known. Distances are frequently estimated out of time-of-flights of a signal sent by the target node to a set of given landmarks. However, most of WiFi network protocols do not support time measurements with the accuracy required for this purpose. As a consequence hardware specially developed for this purpose is also needed.

The technology presented here provides time-of-flight accurate enough measurements without need of customizing the hardware or modifying the network interface drivers.

The technology consists of two software modules that are run within the wireless nodes used to calculate a position. The node will use that interface to perform a ping process, i.e., send a packet (or frame or cell) and wait for a response (i.e. two-way TOA approach). The initial application of this kind of modules is to compute the time-of-flight of information packages sent via WiFi by the node to the landmarks. Thus, one of the modules traps all the network traffic, associates a time-mark with each packet/frame/cell and builds a local database with this information. The other module matches the pair of packets associated with the same ping process, computes the time-of-flight of the packets and removes the data consumed from the database.

Time of flight is further turned into a distance measurement and the position of the WiFi node is finally computed once the distances from enough number of landmarks are available.

This technology is very effective in tracking the movement of objects and people indoors, management of product storage and other logistics.

The center is looking for partners with interest in co-development of the technology and up-scale of application. Commercial agreements with technical assistance are also sought.

Innovative Aspects:
- It does not require hardware customization
- Software already running in the wireless node is not modified (transparent for the rest of services running in the wireless node)
- Applicable to any technology using a two-way TOA approach
- No need for maintenance: hardware and software modifications do not impact on tracking capabilities
- Suitable for location systems running indoor