Global Positioning Systems (GPS)
WhereNet, Identec Solutions Offer GPS Tracking
GPS, both companies say, will enable end users to track assets even when the installed RFID technology is insufficient to provide the desired level of visibility.
June 18, 2007-Two providers of RFID-based real-time location systems for asset tracking have announced the addition of GPS technology to their offerings. Santa Clara, Calif.-based WhereNet has introduced GPS capabilities to version 4.0 of its Marine Terminal Solution, a hardware/software package for tracking cargo containers in a marine terminal environment. Identec Solutions, based in Lustenau, Austria, has added GPS to its I-Q RFID tag. Both companies say the addition of GPS technology will enable end users to track high-value assets even when the installed RFID technology is unable to provide visibility at the granularity they require.
WhereNet Marine Terminal Solution version 4.0 employs active 2.4 GHz tags that comply with the ISO 24730 standard for real-time location systems. The solution determines the asset locations not by placing RFID tags on cargo containers, but by deploying tags on the large mechanical arms the container-handling equipment uses to move containers from place to place in a marine terminal. WhereNet location sensors, installed throughout the terminal, determine the location of the WhereNet tag (WhereTag) on the container-handling equipment. The Marine Terminal Solution then associates this data with a timestamp of when the equipment sets down a particular container. The WhereNet system identifies each container by pulling its ID number from the optical character recognition camera attached to the crane.
Under this system, WhereNet can ensure location accuracy within 4 feet-which is plenty for finding cargo containers 8 feet wide. By adding the option of using GPS receivers to locate the containers, WhereNet can provide its real-time location system to customers unable to install all of the WhereNet location sensors needed to locate an asset to within 4 feet. To collect the GPS data, WhereNet combined a GPS receiver with a WhereTag active tag. The tag is housed together in a WhereTrack controller, which also contains a Wi-Fi modem. The modem is used to upload applications to the microprocessor, and to send the GPS data over the WhereLAN network of Wi-Fi locating access points, along with the tag ID and the crane's operational data, needed to determine when a container was set down. For sites without Wi-Fi coverage, the controller uses WhereLAN's ISO 24730 2.45 GHz channel for communication back to the location sensors.
In the past, says John Rosen, WhereNet's director of product marketing, companies might have picked GPS-only tracking systems over WhereNet's RTLS in marine environments. One reason, he explains, is that they lacked the light poles or other tall structures needed to install enough location sensors to accurately determine the crane arm's location (and, thus, the container location). Rosen hopes that offering the use of GPS receivers to collect location data will make WhereNet's Marine Terminal Solution attractive to a larger pool of terminal operators.
In addition, WhereNet has modified its Visibility Software Server (VSS) middleware to be able to process GPS coordinate data and link that data to the WhereNet container-tracking application software. Rosen notes that the WhereTrack system provides a means for companies currently using GPS-only systems to increase the visibility of containers as cranes place them in areas where obstructions created by buildings or ship births prohibit the clear line of sight to satellites required by GPS receivers. "We are seeing some sites where a hybrid installation of GPS and RTLS might be the best solution," he says.
Peter Linke, president and CEO of Identec Solutions, says that Identec decided to create a new tag with an integrated GPS receiver-which it calls the GPS tag-partly because recent advances in GPS receiver technology have reduced the amount of battery power the receivers require. This means the company could add the capability to capture GPS data without appreciably reducing a tag's battery life.
Identec is offering the GPS in two versions. One follows the ISO 18000-7 air-interface protocol, which uses IP recently licensed from Savi Technology, a subsidiary of Lockheed Martin (see Seven Companies Sign Up for Savi IP License). ISO 18000-7 is the standard for real-time locating systems that use active tags operating at 433 MHz. The other version operates at 915 MHz, using Identec's proprietary air-interface protocol. Linke notes that Identec Solutions also improved the sensitivity of the tag's receivers, increasing the 100-meter read range of past models to 500 meters.
One other difference between the 915 MHz and 433 MHz tags, Linke says, is that the latter require more time to activate, or "wake up," from the energy-saving standby mode. Both versions transmit GPS coordinates to the reader, along with the tag's ID. The 433 MHz tag works with any ISO 18000-7 compliant reader; however, only Identec's ISO 18000-7 reader can read the GPS coordinates from the tags. According to Linke, Identec Solutions licensed the ISO 18000-7 IP from Savi to attract contracts from the Department of Defense, the biggest user of active 433 MHz tags.
As with the WhereNet system, users will likely rely on GPS coordinates to determine the location of the Identec GPS tag only when an insufficient number of RFID readers are available to determine its location. Linke says the GPS tag allows users to track the movement of trucks within a marine terminal or transportation yard by leveraging the facility's ISO 18000-7 RTLS infrastructure, then continue following the truck's location as it leaves the yard by recording its GPS location at set intervals.
