The Dallas Police Department improves the effectiveness of its remote CCTV surveillance network by switching from microwave transmission to cellular.
To gather evidence in surveillance of drug dealers for investigations, a police unit replaced microwave technology with a cellular network.
The narcotics unit of the Dallas Police Department requires remote video capabilities for evidence gathering in ongoing investigations of drug dealers and for general surveillance of suspects. The department used camcorders equipped with microwave technology to record and transmit surveillance video, but it was not the best technology for this application because microwave transmissions require an unobstructed line-of-sight. When officers needed the cameras to see around a corner or transmit signals through a building window, the system didn�t work, explains Detective Stephen Ledbetter, of the Technical Operations Unit in the Narcotics Division of the Dallas Police Department. Another approach was sought.
After looking unsuccessfully for an alternative solution, Ledbetter contacted Mobile ID Solutions, of Dallas, and worked in partnership with them to devise a system that would work.
Ledbetter told the head of Mobile ID Solutions, Corbin Gerard, about the different problems the department was encountering. Together they put together a complete video system using an Axis Internet protocol camera. The Axis camera is a pan/tilt/zoom unit with a commercial router designed to hold up to abuse. The routers are also equipped with a cellular air card, which allowed the camera to send the video via a traditional wireless network.
"This unit solved our problem, because we were able to provide a video signal over cellular telephone lines using a secure network," says Ledbetter. "We could then view it through various laptops over a secure Internet site or within range of a wireless secured network."
The system has other features that have proved useful. For example, the system has servers that can convert analog cameras to digital cameras. This allows Ledbetter to expand the network when necessary. "We can use any kind of camera that we have and play it over the cell phone network," he says.
The cameras have numerous uses. Each of the Axis cameras has an optical zoom of 26x. It is able to record movement up to a mile and a half away. This means that the narcotics squad is able to conduct surveillance of a drug location before officers move in. The squad can also view a home before officers attempt to execute a search warrant to see whether doors are open or whether burglar bars are on the windows. The unit has even used the cameras to view activity on rooftops two miles away.
"The cameras help us answer questions that we normally would not be able to answer until we are on the scene," says Ledbetter. "Is our primary suspect at the location? How many people do we have in the front yard? How busy is it?"
Once the narcotics division has viewed the location, the information gathered can be relayed to the officers going to the scene or to the department�s SWAT team if they are responding. "We know exactly what is going on at a scene minutes before we arrive at it."
To use the cameras, Ledbetter's team places them in covert enclosures such as a cardboard box on the side of the road or an ice chest in the back of a car or a pick-up. They have also been stowed under piles of clothes in the back seats of cars. The cameras require a space of at least 4 inches by 5 inches.
The system has its drawbacks, according to Ledbetter, but these have been limited to the network, rather than the cameras. For example, there must be a strong cellular signal. "We have had problems because we haven't had cell service or were inside a building with no cell service," he says.
Also, the cellular network has led to slow video feeds. According to Ledbetter, the frame rate is currently one frame every three to four seconds. But when the cellular network traffic is heavy, the frame rate can lag, dropping to one frame every 30 seconds. For example, during evening rush hour when everyone is leaving work, the frame rate slows significantly because of heavy call traffic.
The solution may lie with the cellular service provider. "What we are looking forward to is an updated system from Verizon," says Ledbetter. This upgrade will increase the frame rate to 15 frames a second�this is near real time. (At press time, the upgrade was expected in the first quarter of this year.)
Ledbetter's team has been using the cameras for ten months and is one of the first law enforcement agencies in the United States to fully deploy a surveillance system of this type. Shortly after Ledbetter implemented the technology, the department's narcotics division used it to seize multiple caches of drugs in a single operation.
(For more information: Valerie J. Wehler, marketing manager, Axis Communications, Inc., 978/614-2069; e-mail: email@example.com . Corbin Gerard, principal, Mobile ID Solutions, 714/922-1134; e-mail: firstname.lastname@example.org .)
Teresa Anderson is a senior editor at Security Management.