Giving Law Enforcement a Head Start With Radio-Frequency Technology
Emergency Management
September 28th, 2010
Most United States law enforcement agencies have been discouraged by the low accuracy, lack of timeliness and poor reliability of information delivered by traditional wireless location technologies. They also aren't equipped to put state-of-the-art capabilities to work in fighting crime.
Radio frequency "pattern-matching" technology provides critical breakthroughs. Radio frequency has been enhanced and proven in deployments for E911 emergency services in the United States and for lawful location interception in other parts of the world. The software-based wireless location technology provides real-time, high-accuracy capabilities that can give an agency a dramatic head start in an investigation.
There, Right Now
There are numerous ways that wireless location capabilities could be brought into play in law enforcement investigations. The issue is that traditional geolocation technologies aren't powerful enough for law enforcement's needs. Most conventional systems can place the location of a mobile device user to within a radius of 300 to 500 meters (roughly 900 to 1,600 feet). But in many cases, it's not enough to know which individuals might have been in the neighborhood at a certain time period of a criminal event; law enforcement personnel need to know who is there right now.
Law enforcement agencies' reliance on wireless-location solutions is typically low. They know they can, for example, subpoena wireless operators for location data on a stolen mobile device. But in practice, agencies are not overly interested because the data this yields are neither timely nor precise enough to sufficiently enhance investigations. How valuable is it, for example, to learn that a missing mobile device was within 500 meters of the intersection of Fourth and Main streets an hour and a half ago?
The technologies underlying conventional wireless locations are ill suited for investigative purposes. Vague accuracy is the downfall for Cell Identification/Enhanced Cell Identification technologies since they depend on cell tower location, distance from tower (timing advance) and in some cases signal strengths. In dense, urban areas and indoors, technologies like Assisted GPS perform poorly since they depend on line-of-sight with at least three satellites.
Also, GPS can be disabled, jammed or spoofed. Uplink Time Difference of Arrival (U-TDOA) requires complex-to-negotiate, expensive deployment of radio hardware on all operators' cell towers for triangulating uplink signals. The U-TDOA performance is also driven by line-of-sight conditions and hence limited in dense, urban and indoor environments. Wi-Fi is typically not available on most user handsets and if available, can be easily disabled. Also, Wi-Fi-based location does not provide the consistency, reliability or accuracy required, especially in deep indoor environments. None of the technologies consistently deliver the array of benefits necessary to enhance their investigations, and so agencies historically have passed on significant usage.
