High-Accuracy Wireless Location
Written by Bhavin Shah   

In recent years, local, state, and regional law enforcement agencies have greatly increased their use of all types of technology to fight crime. One of the leading types of technology in use by these agencies is high-accuracy wireless location: providing the precise location of a suspect by tracking his mobile device.

Law enforcement agencies regularly depend on location technology to perform a variety of actions, assisting in the investigation and apprehension of the “bad guys”. These activities include tracking suspect movements, predicting future activities based on intelligent analytics, and monitoring parolees after they have served their sentences. In all these cases, high-accuracy wireless location provides a crucial advantage in protecting citizens and property, and is proving to be an indispensable tool for law enforcement professionals.

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Improving the wireless location bottleneck for law enforcement

A major area of focus for law enforcement is tracking suspect locations through the use of cellular phones and other wireless devices. In order to comply with federal and state laws, law enforcement agencies must typically present a search warrant, a court order, or a formal subpoena to a wireless network operator—such as Verizon or AT&T—in order to gain access to a suspect’s location.

According to a recent Congressional inquiry led by Massachusetts Congressman Edward Markey, law enforcement agencies in the United States issued 1.3 million requests for wireless subscriber information in 2011. These requests for subscriber call records and subscriber location, specifically aided by GPS, have come into question by privacy advocates and the courts, but a final ruling on constitutionality has not been made. There are, however, more mundane concerns that impact the usefulness of what could be a game-changing tool in anti-crime efforts.

The process by which a law enforcement agency obtains subscriber location information is considered cumbersome and antiquated by both law enforcement and the wireless industry. After obtaining the warrant and issuing a request to the wireless operator, the law enforcement agency often must navigate multiple offices and contacts within the operator organization to get the requested information. At stake is money (cash-strapped law enforcement agencies would like to scale back the number of man hours devoted to manually processing requests to and responses from wireless operators) and time (an “immediate” response to a law enforcement request may still take up to eight hours, for which wireless operators often charge a premium—explicitly allowed by federal law).

Even after going through that process, subscriber location information may not be accurate. Most operators rely on GPS to identify suspect location, which assumes that (a) the suspect is in possession of a GPS-enabled phone, (b) that he has not disabled the GPS chip inside the phone, and (c) that he is not indoors where it is nearly-impossible for GPS satellites to obtain a location fix. If any of those conditions are not met, then the requested location information is not useful.

So what would an ideal solution look like? Law enforcement agencies agree on the need for a solution that tracks non-GPS enabled location information from the operator network, and enables a robust surveillance application at the law enforcement agency site, eliminating the need for costly and time-consuming information requests to operators. Fortunately, both conditions are being met by new technology developed in the United States and in place today.

A standards-based alternative location method is Radio Frequency Pattern Matching (RFPM). This network-based positioning method uses the device’s own radio signals to identify its location, eliminating any dependency on satellites or other network hardware. RFPM is able to locate all callers across any air interface and in any environment, eliminating limitations related to the device type or network technology. RFPM works extremely well in non line-of-sight conditions such as dense urban and indoor environments and cannot be disabled by the suspect, unlike GPS, making it highly reliable for mission-critical law enforcement needs.

With RFPM in place, law enforcement’s first condition is met. For the second—a locally deployed surveillance system that eliminates the troublesome requests to wireless operators—one must look overseas for an example. Several countries have deployed customized surveillance applications that connect directly to the wireless operator network while presenting an easy-to-use interface that is directly accessible by law enforcement. With this tool, law enforcement can locate and track suspects in real time, as well as locate all wireless devices in a specific location at a specific time. Wireless operators currently charge $50-75 per hour per cellular tower for these so-called “tower dumps” that are vital to law enforcement in a public emergency such as a bombing or natural disaster. Of course, cooperation by the wireless operator would still be required, and the solution would need to be adapted to meet warrant guidelines and to satisfy privacy advocates. Once in place, this RFPM-enabled surveillance system would make the job of law enforcement substantially more efficient—saving time, money, and lives.

Using intelligent analytics to predict movements

The Obama administration relaxed restrictions on how law enforcement is able to search, retrieve, and store data gathered by government agencies for purposes other than national-security threats. Private information on U.S. citizens (for example, credit-card data or travel records) will be stored for five years, and these databases will be subject to data mining—the use of complex algorithms to search for patterns that predict a threat. The reported driver for this was the failure by intelligence agencies to “connect the dots” about the December 2009 “underwear bomber”, despite having intercepted mobile phone communications and field reports on the attacker.

Privacy advocates have raised concerns, but this move is a positive step in using intelligent analytics to prevent attacks on lives and property. The goal of intelligent analytics is to enable a law enforcement analyst to filter a large set of possible suspects using multiple inputs and an algorithmic engine with rules. Consider this hypothetical use case:

A known leader of an international terrorist group is traveling to San Francisco to hire new recruits for the group’s U.S. operation. When the target visits San Francisco, he meets with various people in several locations in the downtown area, some more often than others. He meets with select people twice a week, others less often. He has been occasionally calling or texting several local phone numbers before and after his arrival. He has been meeting and calling select people at odd hours.

Intelligent analytics takes these inputs and identifies patterns to assess threats presented by the target and his associates. The important addition of high-accuracy location data to the set of inputs elevates the analysis beyond what can be achieved by only reviewing financial and travel records.

Location analysis immediately depicts relationships between suspects as well as the objects of focus for the suspects. For example, if location analysis showed the target repeatedly visiting the Golden Gate Bridge during a period when he was meeting with local suspects already on a government watch list, and credit-card records showed him purchasing bomb ingredients, then one could reasonably deduce that an attack on the bridge was imminent. This is admittedly a simplistic example, but modern analytics engines are capable of reviewing millions of records to “connect the dots.” The administration’s recent move to allow them access to data for a longer period will only strengthen these capabilities.

Efficiently and inexpensively monitoring parolees

Predicting movements of a suspect demonstrates the effectiveness of location technology at the beginning of an investigation, but what about the end of the process? Once a criminal is arrested, tried, convicted, and has served time, his movements are still liable for monitoring when he is a parolee. Monitoring bracelets have long been used by local governments as a cost-effective way to track criminals and parolees. Recent cuts in state and local budgets continue to drive demand for this tracking, a type of location-enabled machine-to-machine (M2M) solution. In addition, attempts to rectify deficiencies in the current monitoring system (California reports it has lost track of one-fifth of the 127,000 parolees it supervises) and the desire to deploy more sophisticated devices have lead governments to seek out the next generation of location-enabled M2M solutions.

States are spending on average $525 per day to track offenders using GPS, but given the limitations of that technology, many are seeking location-enabled monitoring devices that depend on technologies such as RFPM that enable parolees to be tracked indoors and in other non line-of-sight conditions, while being tamper-proof.

A more recent dilemma facing state governments is how to continue to monitor increasing parolee populations with reduced manpower due to budget cutbacks. One possibility is an M2M solution that enables government authorities to establish virtual perimeters (called “geo-fences”) around a designated location, such as a school, and generate an automatic alarm and police dispatch whenever the geo-fence is breached—for example, by a sex offender on parole. This eliminates the need to have a constant live monitoring presence while providing no less protection to the community.

Another example of an M2M monitoring solution helping governments reduce their dependency on manpower is by enabling alerts whenever two or more parolees are in the same location. If members of a gang are prohibited from meeting as a condition of their parole, the solution can be set up to generate an alarm and police dispatch whenever the designated parolees’ monitoring devices are within a preset distance of one another, such as 30 meters. This eliminates random chance occurrences and is accurate enough to only alert to situations where the two parolees are in close physical proximity. In addition, by relying on RFPM, government authorities can monitor potential meetings in indoor locations, eliminating yet another opportunity for criminal activity.

The above examples demonstrate the breadth of capabilities that high-accuracy wireless location technology provides to law enforcement. It equips them with the means to conduct activities ranging from the most sensitive national security efforts to mundane parolee tracking. At the same time, location technology enables a more efficient and inexpensive approach to law enforcement, a vital attribute in the current economic climate, and proving itself yet again to be an essential tool.

About the Author

Bhavin Shah leads the global Marketing and Business Development activities for Polaris Wireless and is responsible for Polaris Wireless’ North American direct telecom business with wireless carriers. He has more than ten years of experience in the wireless telecommunications industry. Shah is a regular speaker at wireless industry conferences as well as events related to technology for the government sector.

View this article in its original format in our March-April 2013 Digital Edition

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