“Our customers expect fast, accurate emergency response... after extensive research, SimmetryPCS chose the Polaris Wireless WLS software-based solution network over other hardware based solutions because it provided the industry's highest location accuracy with the greatest reliability and at lowest cost of ownership for our GSM network.”

“When widely deployed, wireless terminal location techniques based on signal signatures will provide location information over a wider service area and more accurately than other location techniques based on Time Difference of Arrival (TDOA), Angle of Arrival (AOA) or Augmented GPS (A-GPS). Both TDOA and AOA require reliable signals for at least three base stations to provide location information, but these are not available for many user locations. Also, heavy multipath severely degrades the accuracy of both time difference and angle measurements. A-GPS degrades or does not work at all when too many satellites are blocked from view in city streets and within buildings where the augmentation cannot overcome the losses for enough satellite paths. Signal signature location techniques do not suffer from these problems. Often the ‘richness’ of signatures in heavy multipath improves the accuracy of this technique. Signature techniques can provide some location information from fewer than three base stations (although with degraded accuracy).”

“Just as buildings make a unique visual impression, they also impart a unique radio shadow loss at each mobile location to signals from surrounding base stations. The Wireless Location Signatures method makes use of the unique shadowing properties of buildings to determine where a mobile is. Other methods, such as GPS and TDOA, were created for line-of-sight propagation conditions and are degraded or defeated by shadowing. The Polaris Wireless Location Signatures (PWLS™) technology makes use of what is a unique feature of cities, rather than trying to force a line-of-sight solution into the shadows.”