Asset Tracking Glossary: The Terms Behind the Map

What is asset tracking, and how is it different from asset tagging?

Asset tracking means recording where equipment, tools and vehicles are, and where they have been. Each item carries a tag or a tracker. Software keeps every reported position with its time, so you see the latest one and the history.

Asset tagging is the step before it. You fix a label or a tag to an item and link it to a row in your asset list. A printed label says what an item is. A tag that passing phones report also says where it is.

The asset tracking terms below are grouped by topic, with related words side by side.

Asset tracking glossary: GPS, BLE, RFID, UWB and Wi-Fi

Asset tracking systems are built on these radio technologies. Some work out where an item is. Others identify an item when a reader or a phone hears it.

• GPS and GNSS

  GNSS is the general term for satellite navigation systems. GPS is the United States system, and its name is often used for all of them. A receiver works out its own position from satellite signals. A GPS tracker then sends that position over its own data link. So each unit needs power and a data plan.

• Bluetooth Low Energy (BLE)

  A low-power radio standard used by many battery tags to broadcast a short identifier. The low power draw lets a tag's battery last up to six years, depending on its size.

• RFID

  Radio-frequency identification identifies an item when a reader detects its tag. Passive RFID tags carry no battery, and the reader powers them for each read. Active RFID tags carry a battery and broadcast on their own. Readers are fixed at doors, dock gates and checkpoints, or held in the hand.

• Ultra Wideband (UWB)

  A radio whose signals can be timed very precisely between compatible devices. In an RTLS, UWB anchors installed around a building use those timings to locate the tags.

• Wi-Fi positioning

  A device estimates its position from nearby Wi-Fi access points whose locations are known. Phones combine it with satellite signals, which helps indoors.

Each of these needs something before an item shows on a map. RFID needs a reader where you want a read, and a GPS tracker needs a data plan per unit. A crowdsourced tag needs neither. The RFID vs Bluetooth vs GPS guide sets out what each one needs.

What is RTLS? Real-time location system terms

• RTLS (real-time location system)

  RTLS stands for real-time location system, also called a real-time locating system. It locates tagged items inside a building or another contained area with little delay. Receivers installed on site hear each tag, and software calculates its position on a floor plan. It can be built on BLE, UWB, Wi-Fi or active RFID. The term usually does not cover GPS or phone tracking. ISO/IEC 24730 is one international standard series for it.

• Anchor, reader and locator

  The fixed receivers an RTLS mounts on walls and ceilings across a site. UWB systems call them anchors, RFID systems call them readers, and BLE systems often call them locators or gateways. Their number and placement decide which areas are covered.

• Location engine

  The software that turns receiver readings into a position. It combines what several receivers heard from the same tag, then places the tag on a floor plan.

• RSSI

  Received signal strength indicator is how strong a signal was when it arrived. A stronger signal usually means a nearer tag, so RSSI gives a rough position. Walls, metal and people change it.

• TDoA and ToF

  Time difference of arrival compares when one signal reached several receivers. Time of flight measures how long a signal took to travel. UWB systems use these timings to calculate a position.

• AoA and AoD

  Angle of arrival is the direction a signal came from, measured by a receiver with several antennas. Angle of departure turns this around, with the antennas on the sender. Bluetooth 5.1 added both for direction finding.

An RTLS covers the areas where its receivers are installed. The RTLS system cost guide sets out what each covered area needs, from receivers and power to battery changes.

A crowdsourced tag works another way. Nothing is installed on site, and any phone that passes reports it. One tag can be reported at the yard and at each job it goes to.

How does a tag's location reach the map?

Any phone that passes the tag carries its location there. The phone hears the tag's short signal, adds its own position and the time, and sends that report to the service. The tag itself has no GPS and sends no position.

• Tag

  A small battery device fixed to an asset that broadcasts a short signal. Printed barcode and QR labels are also called tags, but someone has to scan them.

• Tracker

  A device that works out its own position, usually by GPS, and sends it over its own data link. It runs on vehicle power or its own battery. The words tag and tracker are often used loosely, so check how a device gets its position.

• Gateway

  A fixed or vehicle-mounted receiver that hears nearby tags and forwards what it heard to the internet. On a crowdsourced network, each passing phone does this job, so nothing is installed.

• Crowdsourced finding network

  A network in which any phone that passes a compatible tag reports where it heard it. These networks are large (Apple counts over a billion iPhone, iPad and Mac devices, and Google over a billion Android devices). A tag on one needs no wiring, receiver or data plan.

• Location report

  The message a passing phone sends when it hears a tag. It holds the phone's own position and the time. Apple and Google both say these reports are encrypted, so not even they can see the location.

How a crowdsourced network works follows one report from a tag to the map.

What does last seen mean? Data age and accuracy terms

Last seen is the time and place of the most recent report for an item. For a crowdsourced tag, it is the latest time a passing phone reported it. A good map shows that time beside each pin. The terms below explain how old a position is and how close it sits to the item.

• Location fix

  A position calculated at a stated time, usually by a satellite receiver. Read the time with the coordinates, since a fix can be accurate and still old.

• Sighting

  A record that a phone or receiver heard a tag at a time and place. The position is the phone's own, which puts the tag close to it.

• Reporting interval

  How often a device sends a new record. A crowdsourced tag is reported when phones pass it. A busy yard updates all through the day. A remote yard updates when someone comes by, and more often once the unit reaches a busier place.

• Latency and data age

  Latency is the delay between an observation and its arrival in the software. Data age is how old the latest record is when someone looks at it.

• Accuracy and precision

  Accuracy is how close a position is to the true one. Precision is how close repeated positions are to each other. A sighting is only as accurate as the reporting phone's own position.

What is a geofence? Alerts and location history terms

• Geofence

  A boundary drawn on a map around a real place, such as a yard or a jobsite. The software compares each new position with it and records an entry or an exit.

• Dwell

  The time an asset stays inside or outside a boundary, such as how long a trailer stayed at a customer. A dwell rule can raise an alert after a set time.

• Event and alert

  An event is a recorded change, such as a boundary exit. An alert is the message sent because a rule matched an event, such as an email.

• Location history

  Every stored fix or sighting for an asset, in time order. It answers where an item was on a given day, and it can be exported for a claim or an audit.

• Route playback and breadcrumb trail

  Two ways to show location history on a map: as an animation, or as a line joining the points in time order.

The geofence guide shows how to draw one around a yard or a jobsite.

Vehicle telematics terms: CAN bus, OBD-II, ELD and HOS

• Telematics

  Remote collection of vehicle or equipment data, such as position, speed, fuel, fault codes and engine hours. The data usually comes from a device wired into the vehicle.

• CAN bus and OBD-II

  The controller area network (CAN bus) carries messages between a vehicle's control units. OBD-II is a standard diagnostic port that exposes some of that data. The fields available vary by make and model.

• ELD, HOS and RODS

  An electronic logging device connects to a commercial vehicle's engine and records driving time. Hours of service (HOS) rules limit driving and duty time, and the ELD keeps the driver's record of duty status (RODS). Each ELD in use must be on FMCSA's list of registered, self-certified devices (FMCSA ELD guidance).

• Utilization

  How much an asset is used. It can be counted as days seen on a site, or as runtime from an hour meter or engine data.

Inventory and custody: asset ID, check-out and chain of custody

• Asset tag

  The marker fixed to an item. It can be a printed label, a barcode or QR label, an RFID inlay, or a battery tag. The asset tracking tags guide covers mounting one.

• Asset ID and hardware ID

  An asset ID is your own permanent code for the item, such as DRL-014. A hardware ID identifies the tag on it. Keeping the two apart lets a tag be swapped without changing the item's history.

• Asset register

  The master list of items an organization owns, one row per item, with its asset ID, serial, home location and status. Asset tracking templates lists the columns.

• Check-in and check-out

  A record of a handoff: who took an item, when, in what condition and when it is due back. The equipment sign out sheet is a template for one.

• Custody

  Who was responsible for an item during a period. A signed check-out row records who. A location record shows where.

• Chain of custody

  A controlled record of every hand an item passed through, used for evidence and regulated material. It relies on signatures, seals and an audit trail.

Asset tracking glossary: APIs, webhooks, exports and access

• API

  An application programming interface lets one piece of software read or change data in another, with set permissions and formats. Published documentation lets your own developers estimate the work.

• Webhook

  A message one system sends to another when an event happens, such as a geofence exit. The receiving system learns of the change without asking.

• Polling

  Asking a system for new records on a schedule, such as every five minutes. It is simple to build, and new records arrive at the next request.

• CSV and JSON export

  CSV is a flat table that opens in a spreadsheet. JSON keeps nested fields for software to read.

• System of record

  The system whose value wins for a given fact. An ERP may own the asset list, while a tracking system owns the location history.

• Data retention

  How long records are kept before they are deleted or summarized. Contracts usually state it for each kind of data.

• Authentication and authorization

  Authentication checks who is signing in. Authorization decides what that person may see or change.

• Audit log

  A dated record of sensitive actions, such as a sign-in, an export or a change of permissions.

The data export and API guide covers location exports and the API in more detail.