AeroScout updates location-tracking wares

AeroScout is the latest location-tracking vendor to unveil a new Wi-Fi-based radio tag. Its new model is markedly thinner than its existing tags and sports a built-in motion sensor and two programmable buttons for sending simple acknowledgements or alerts.

Due out in the next few weeks, the AeroScout T3 Tag, like the existing T2, is fitted with an embedded 802.11b radio and powered by a tiny, replaceable lithium battery with a life of up to four years. With its new size and design, the tag is intended to be carried or worn more conveniently by workers or patients. The buttons allow users to signal the availability of a tagged person or asset, or indicate that an asset has been used and needs to be cleaned, serviced or restored.

Recently rivals in the active RFID, or location tracking market, likewise announced additions to their product lines. Ekahau and PanGo announced new Wi-Fi-based active tags, and PanGo unveiled a new version of its core software for location services. Wireless LAN (WLAN) vendor Trapeze rolled out a new location appliance based on hardware and software from Newbury Networks.

In two of its three dimensions, the new tag is actually slightly larger than the older T2, which AeroScout will still offer. But it’s the third dimension — thickness — that’s critical, says Josh Slobin, director of marketing for the vendor.

The T3 is just under 3 inches wide, just under 2 inches tall, and just under a half-inch thick. The T2 is about 2.5 inches wide, 1.5 inches tall, and two-thirds of an inch thick. “When you actually hold the tags in your hands, you can see and feel the differences,” Slobin says. “The T3 is noticeably flatter.”

As a kind of thick credit card, instead of a compact radio, the T3 will be easier for staff to carry around, making location tracking for, say, patients, simpler and easier. A plastic loop at the top accepts a lanyard for wearing around the neck or a clip to attach to clothing.

Like the older tag, the new one is designed to work with any existing WLAN infrastructure. The T3 will use a special subset the Cisco Compatible Extensions (CCX), which are Cisco interfaces designed to let WLAN clients tie easily and quickly into Cisco access points. The new, lightweight subset is specially designed for Wi-Fi tags.

Unlike some rival Wi-Fi tags, however, the AeroScout tags do not actually associate with an access point. Typically, a Wi-Fi tag behaves just as awireless laptop: It scans for an access point, creates a data packet, sends this to the access point, handshakes with it, associates, and then transmits data packets.

But when an AeroScout tag emits a radio signal, it simply sends a header message with the tag’s media access control address. The access point’s firmware identifies this unique message and, with some coding changes by the manufacturer, simply passes it to the AeroScout Engine, which is a server application, or to a box such as the Cisco 1200 Location Appliance, to process and pinpoint the tag’s actual location. The location is then mapped and displayed via AeroScout’s MobileView application.

AeroScout’s approach means the tags don’t show up as full clients on the WLAN and don’t need IP addresses or additional management resources. These “light” 802.11b clients also don’t bog down 802.11g access points, which otherwise drop from a data rate of 54M to 11Mbps when an 802.11b client associates.

Another distinctive feature is a built-in motion sensor. The sensor detects when the tag is moving and can trigger a faster signaling rate so back-end systems can track the tag; when the tag is motionless, the signaling rate drops, conserving power. Motion also can trigger the tag to send an alert if a medical device or other asset is supposed to be used only during certain hours, for example. Movement at a different time activates the alert.

The T3, like the T2, can work in both indoor and outdoor wireless networks. AeroScout uses different location calculation algorithms for each: receiver signal strength indication indoors and time difference of arrival outdoors, where RSSI is less reliable, Slobin says.

The T3 tag will ship in the next few weeks. AeroScout declined to disclose the price of the new tag, which is sold to and through channel partners, but did say it would be similar to the T2, which in single quantities is priced at $65 and volume discounts are available, according to Slobin.