Hybrid location technologies: GPS, RFID and other technologies

A typical RFID tag with an active antenna

Continued from our previous report: There are other potential technologies for finding a mobile user’s location such as Bluetooth beacons, indoor messaging systems (IMES), machine-to-machine (M2M) communications, near-field communications (NFC), radio-frequency identification (RFID), and ultrasonic beacons. Many of these techniques aren't yet widely used; except for RFID, but that may change in the near future.

RFID tags can be installed in certain pre-determined locations and then serve as reference position generators for other positioning technologies such as sensors.  More commonly, they can be used with GPS/GNSS stations to geotag the RFID tag at a particular location - something that is now fairly popular for group sports, such as triathlons, marathons, and skiing.

Many lift tickets at major ski resorts now include RFID
Not only do they indicate the status of the lift ticket,
but when combined with geotagged readers at the lift
the skiers can be provided information about lifts they
visited at the resort.

Logistics and transportation are major areas of implementation for RFID technology. Yard management, shipping and freight and distribution centers use RFID tracking technology. In the railroad industry, RFID tags mounted on locomotives and rolling stock identify the owner, identification number and type of equipment and its characteristics. This can be used with a database to identify the lading, origin, destination, etc. of the commodities being carried.

When combined with the GPS/GNSS location of the locomotive, or trucking transportation system (using vehicle tracking systems)- specific orders and equipment can be located in near-real-time (if they are in a wireless coverage area).  For instance - in produce transportation (which is usually RFID tagged), additional information from the vehicle tracking system can also indicate the temperature of the produce during the transportation process.

RFID tagged packages can be geotagged using vehicle or
fleet tracking systems that utilize GPS/GNSS for location
tracking.

In commercial aviation, RFID technology is being incorporated to support maintenance on commercial aircraft. RFID tags are used to identify baggage and cargo at several airports and airlines.

Many hospitals also utilize RFID tags for patient tracking, as well as to keep track of critical and potentially dangerous drugs.

Some countries are using RFID technology for vehicle registration and enforcement. RFID can help detect and retrieve stolen cars.  RFID cards are used for access control to public transport.
In London travelers use Oyster Cards on the tube, buses and ferries. It identifies the traveler at each turnstile and so the system can calculate the fare.  It's possible in the future that vehicles may include RFID tags for licensing, and VIN identification.

A runners RFID gate.  It is geotagged
when it is setup using GPS/GNSS and
as the runners pass through the gate
or over the pad, their identifying RFID
is geotagged and time-stamped, and
Wi-Fi is used to transfer the information
to a central database - and then
forwarded for near-real-time updates on
the runners progress - or for later
analysis with additional data.

Due to some poor marketing information, there has been some confusion regarding the functionality of RFID and GPS/GNSS; some have thought that the RFID tags can be used for location tracking on their own.  That is not the case.  RFID tags must be used with an RFID 'reader' that is in the proximity of the RFID tag.  The reader itself may be geotagged, so that the general location of the RFID tag can be registered for that time and date - but without the RFID reader and an additional geotagging location system, the devices cannot provide their current position.

One of the key enablers of hybrid positioning is an entity that can intelligently determine which positioning technique to use depending on reported readings from the mobile device. This entity may reside on the mobile device, on the network, or on some combination thereof. For example, the central database server for Wi-Fi positioning may be on the network, but a client on the device could get “snippets” of the database relevant to the current location. Termed the positioning engine, it can implement a position calculation function (PCF) using Kalman filters to process input data from a variety of sources, for example.

Hybrid location technologies simultaneously carry out all of these positioning techniques. Depending on the reported readings, the positioning server prioritizes certain methods over others. In addition, methods that provide a fast, low-accuracy fix may be prioritized over those that are slow but provide high-accuracy fixes.

RFID tags for runners can be included on
the shoe, or the wrist.  The shoe is usually
preferred since it is closer to the RFID reader.

Positioning may occur in MS-assisted (mobile station) or MS-based mode. In the MS-assisted mode, the positioning server calculates the final position based on measurements provided by the mobile device. In MS-based mode, the mobile device (smartphone, vehicle tracking device, etc) calculates the position based on its own measurements and optionally reports the final position to the server - either in near-real-time, or as a passive store and forward function.

RFID tracking for marathons would be considered an MS-assisted mode, since the geotagged and time-stamped information regarding the runner is done at the RFID gate.

Smartphone tracking using GPS/GNSS would be MS-based mode.

One of several fitness bands currently
available on the market.

A combined or hybrid system could use both technologies - the RFID tracking system to provide near-real-time runner location. Using a local smartphone system, combined with a Bluetooth biometric system such as a fitnessband or activity tracker.  The fitness band sending information to the connected smartphone system which then combines location, altitude, instantaneous speed, a highly accurate time-stamp, and the biometric data collected such as heart rate, oxygenation levels, calories burned, etc.

This data can be forwarded from the smartphone (as a wireless network is available during the activity) to the central server that is also collecting RFID location data for the runner.  The server can then post-process any critical biometric data to provide additional alerts or updates (via email or SMS) to either the runner, family, or coaching staff as needed.

Hybrid tracking systems are likely to be used more in the future as technology progresses in order to provide multiple redundant methods of location tracking under changing environmental conditions, as well as to provide geotagged data for more sophisticated analysis and functionality.