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LOST - Essensium's ranging and positioning solution

Ranging

Essensium's LOST technology (LOcation system for Sensor Tracking) is capable of offering sub-meter accuracy in indoor environments and can maintain this accuracy over hundreds of meters.

This RTLS (real-time location system) technology is based on a Time-of-Arrival approach with Two-Way Ranging (TWR).

The patented LOST technology modifies a short WLAN packet by adding a wide band rising edge. Therefore, LOST is co-existent with WLAN and has similar range with on top high accuracy ranging and short ranging time.

LOST Two-Way Ranging principle

The advantages of this technology are:

  • Accuracy: because of wide-band rising edge, LOST ranging is capable of better than 50cm accuracy, putting its performance in line with UWB systems.
  • Range: LOST technology is piggybacked on a WLAN system, with a range larger, than several hundreds of meters.
  • Indoor applicability: Reflections are discarded due to the UWB character of the ranging signal.
  • Synchronization: There is no need for synchronisation.
  • Scalability: It can track several thousands nodes per second due to the short ranging time .
  • Calibration:there is no need to calibrate to different environments, nodes or frequencies.

Outdoor tests have shown that the LOST RTLS technology maintains its sub-meter accuracy over distances up to 500m, as presented in the diagram below.

Positioning

The LOST positioning functionality is based on the fixed location of a number of base stations that track mobile nodes within their range.

Accurate ranging is not sufficient to develop accurate indoor positioning: obstacles can block the direct path between the mobile node and a base station; one bad measurement can cancel out the accurate measurements of other nodes and spoil positioning.

LOST is capable of countering these issues: indoor obstacles can be handled just like WLAN, and with its software algorithm, LOST is capable of selecting the most probable location of all possibilities allowing better handling of bad measurements. This way, indoor applicability does not require a fixed floor plan or environments where objects cannot be moved.

LOST will also avoid potential interference from the crowded WSN band, since LOST will contend for air time just like another WLAN device, and uses CSMA to avoid collisions. Other interference sources, like microwaves, have the same interference on LOST as on other WLAN devices.

Conclusions

LOST ranging combines the best of WiFi and UWB, and provides:

  • high precision ranging
  • long range operation
  • indoor operation
  • scalable to many nodes/sec

In the following movie, we demonstrate the capabilities of the LOST technology:

LOST is superior for ranging and positioning compared to other technologies.

  • GPS: operation only outdoor
  • WiFi & ZIGBEE: RSSI accuracy worse than 5 meters.
  • UWB: range not larger than 60 meters.
 
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