An overview of the RTLS location technologies from AiRISTA
AiRISTA has an active R&D lab where a range of technologies are put to the test. Some of these technologies are productized and described below. Others, like LoRa and UWB, are evaluated and a design is created in case the market dictates a shift in that direction. This blog is one in a series, and describes the pros and cons of each technology. See our previous blog for a description of each technology.
+ Inexpensive tags make it practical to track many low-value items. Tags may cost pennies or a couple dollars.
+ the tags are small and thin allowing tagging of items like clothing and even paper documents
+ No tag management required s.a. battery replacement
– limited read range, up to 7m
– does not provide x/y location, rather indicates proximity to a reader
+ Any device with a BLE radio, like a cell phone, can be detected as if it was a tag
+ Readers, and in the case of AiRISTA tags, can be configured remotely to dynamically tune sensitivities
+ Battery life of a BLE tag that blinks every minute or so can last years
– Direction of movement of a tag is not possible without multiple readers
– BLE signals are attenuated (diminished) by liquid, so wearing a tag on your body can produce different signal strengths depending on the area of the body worn.
Received Signal Strength Indicator (RSSI)
+ tracks tags in real time throughout a facility provided sufficient density of receivers (e.g. Wi-Fi access points)
+ Its possible that no additional infrastructure is required beyond your existing wireless network.
+ bi-directional communication is possible to relay information like battery levels or to send configuration updates to the tag
– The expense associated with a battery, processor, memory, radios and antenna make it practical to track only your more valuable assets (although costs are coming down quickly like AiRISTA’s new A7 tag).
– Batteries can last days or several years, but a maintenance plan is needed to replace batteries
BLE Angle of Arrival & Angle of Departure (AoA & AoD)
+AoA provides submeter accuracy
+ AoA can track in the vertical dimension
+ Using a novel approach to location calculation AiRISTA’s implementation of AoA can use a single reader to get submeter accuracy making it ideal for clinics, branch offices, small stores, etc.
– AoA requires an overlay network of BLE 5.1 or greater readers (until access point vendors begin to include the technology in their equipment and AoA becomes ubiquitous)
– legacy tags may not be upgradeable to BLE 5.1 (AiRISTA can upgrade most of its legacy tags over the air)
BLE High Accuracy Distance Measurement (HADM)
+ Designed for applications like fobs for vehicle entry, the technology will be widely used and rides down the cost curve expected of consumer products
+ Accuracy is not affected by the human body so accuracy is maintained regardless of the tag’s position on your body
+ AiRISTA’s solution combines AoA and HADM to provide submeter accuracy and tracking in the vertical dimension from a singe reader 3”x2” making it ideal for clinics, branch offices, small stores, etc. This essentially competes more expensive and complex UWB solutions.
– Bluetooth® LE committees have not ratified the standard, but early implementations should be forward compatible
Global Positioning System (GPS)
+ Accurate outdoor tracing to within several meters
+ There is typically no fee associated with use of the satellites
+ GPS does not rely on a terrestrial network and works in remote areas and at sea
* AiRISTA tags combine outdoor technologies with indoor wireless technology to facilitate seamless migration
– GPS does not work well indoors
– GPS is power hungry and can deplete batteries quickly
* AiRISTA conserves battery energy by putting the tag to sleep when not in use
+ Tags require no battery
+ Tags can be printed similar to passive RFID tags and cost pennies
+ BLE receivers in common devices can act as the gateway to relay the tag’s ID
– The technology is pre-standard
– The ecosystem of tag printers and software vendors is immature
– Limited range due to relying on other RF signals to provide power