Impinj, a provider of RFID devices and software, has begun taking orders for a new gateway reader that employs steerable-beam antennas to track the direction of moving passive EPC Gen 2 (RAIN) RFID tags as those tags are being read. The xSpan is the third member of Impinj’s family of gateway readers (following the xPortal and the xArray), which all feature a built-in steerable-beam antenna, also known as a phased-array antenna. The xArray offers a wider read range and more precise location accuracy than the xSpan, the company reports, but is also larger and more expensive.
“We saw a need for customers that didn’t need the precise x and y coordinates [that the xArray provides],” says Craig Cotton, Impinj’s marketing and product management VP. Those customers, however, still required directional information that a reader such as the xPortal could not provide. In some cases, users were installing xArrays to identify the location in which an item was moving, so that they could monitor where it was in real time or understand other information, such as whether a pallet was loaded onto the correct truck, or down which hospital corridor a wheelchair turned while moving through a busy emergency department. If they needed to know only whether a tag moved forward or backward, however (such as onto or off of a truck), or if their need for location information was not very granular, the xArray could be an overpriced solution for their purposes.
Therefore, Cotton says, Impinj developed a product with a forward and backward sweep of antenna beams, rather than the xArray’s circular coverage area, in the form of a reader that could be smaller and less expensive while offering a more limited coverage area. “We were very purposeful to meet a slightly different need,” he says. While the xArray supports a 1,500-square-foot circular coverage area, with 52 polarized beams arranged in nine sectors, the xSpan supports a rectangular coverage area of 1,000 square feet, with 13 polarized beams arranged in three sectors.
The xSpan measures 18.8 inches in length by 8.7 inches in width (approximately half the width of the xArray) and 3.5 inches in depth—and like the xArray, it uses Power-over-Ethernet. It can be mounted on a wall or ceiling, Cotton says, and is designed to be more aesthetically pleasing for such locations as upscale stores. However, it is also well suited for more industrial environments, he notes, since it can be mounted simply on a wall without requiring a dedicated portal, which can take up space and require barriers to protect the hardware from blows caused by forklifts or other vehicles.
Companies using the xSpan to date have mostly been in three sectors: retail, logistics and health care. (None of these businesses are willing to be named.) Retailers are deploying the readers at store entrances and exits, as well as in corridors or doorways between the back room and sales floor. At the exits, the system can detect whether an item with a tag is leaving the store (as opposed to merely pausing near the door) or arriving.
At the transition between the store’s back and front areas, the technology can enable users to identify if a tagged item is being moved onto the sales floor or into the back room. That information enables a store to create a more accurate inventory of goods than it could using a basic portal reader that would simply identify if an item was detected in the transition area, but not indicate the direction in which that product was moving. The xSpan could also be installed on the sales floor or in a storage area, provided that the retailer does not require an RFID coverage area as broad as that provided by the xArray.
Logistics businesses are also using the xSpan as a way to track where goods are flowing into or out of warehouses or staging areas, Impinj reports. For instance, if an xSpan is mounted on a wall at a company’s dock doors, it can identify the direction in which a tagged box or pallet is moving. The user’s software could then issue an alert in the event that the wrong item is being placed onto a truck, based on the tag ID being read and the direction in which it is perceived to be moving.
In addition, Impinj notes, health-care solution providers are purchasing the xSpan to enable their customers to better understand the flow of equipment or individuals through hallways or doors. When the device is mounted on a corridor wall, users will be able to determine where a tagged patient, staff member or piece of equipment is going when the options in that hallway are simply two-directional.
The xSpan is designed for busy environments, Cotton adds, enabling users to identify not only the direction in which a tag is moving, but also when it changes course. “We have algorithms that can detect if the tag stops, pauses, goes straight through or takes a U-turn,” he says. The device can also detect if something has paused for an extended period of time near the reader, he adds, and then apply what he calls “stray mitigation” to determine whether that tag read is a stray (resulting from a non-moving tagged item), while also capturing moving tags in real time. An RFID reader, Cotton explains, “needs quite a bit of sophistication to handle all those scenarios.”
Orders for the xSpan will begin shipping next month. The reader is priced at $2,500—about two-thirds of the xArray’s cost.
“Our vision is to have a whole family of gateways,” Cotton states. “We now have three gateways, and I expect there will be more.”
Two other companies make readers with internal steerable-beam antennas—View Technologies (see View Technologies Launches Long-Range RTLS for Passive UHF Tags) and Mojix—while Tyco Retail Solutions offers an external steerable-beam antenna, the IDA-3100, designed to be used with Tyco’s Sensormatic IDX 2000 or IDX 8000 reader (see Tyco Retail Solutions’ Steerable-Beam Antenna Brings Movement Data to Retailers). The range, accuracy and cost of those systems vary, according to Bill McBeath, ChainLink Research‘s chief research officer. “There are probably scenarios where some degree of precision and range [provided by a product like the xSpan] matters,” he says, “like if someone changes directions one or more times while in read range.” With a simple portal reader, he adds, “the ability to detect which direction they ultimately exited the doorway might prove to be challenging.”