Glossary

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A* Path Planning(also: A-star algorithm, A* search)

A classic graph-search algorithm (Hart, Nilsson, and Raphael, 1968) that finds the shortest or lowest-cost path between two points by combining the cost already travelled with a heuristic estimate of the remaining distance. In assistive indoor navigation for blind travellers, A*…

AR Marker(also: Fiducial marker, Augmented reality marker)

A printed visual pattern (often a square with a distinctive black-and-white code) placed in the environment that a smartphone or AR headset camera can recognise to determine its own position and orientation with high precision. In blind-navigation research, AR markers are placed…

Accessibility Map(also: Accessible Route Map, Wheelchair Accessibility Map)

A map that displays information about the physical accessibility features and barriers of an environment, such as the presence of curb ramps, steps, slopes, surface conditions, and accessible entrances. Accessibility maps are essential tools for people with mobility…

Accessible Pedestrian Signal(also: APS, Audible Pedestrian Signal, Audible Traffic Signal)

A device integrated into pedestrian signal systems at traffic intersections that communicates walk and don't-walk information to pedestrians who are blind or have low vision through audible tones, verbal messages, vibrotactile surfaces, or a combination of these. APS devices…

Accessible Pedestrian Signal(also: APS, Audible Pedestrian Signal, Talking Traffic Signal)

A traffic control device that communicates pedestrian signal information in non-visual formats, typically through audible tones, speech messages, or vibrating surfaces, enabling blind and visually impaired pedestrians to know when it is safe to cross a street and in which…

Accessible Routing(also: Accessible Navigation, Barrier-Free Routing, Accessible Wayfinding)

The calculation of travel routes that account for accessibility barriers and the specific mobility needs of disabled pedestrians. Unlike standard navigation that optimises solely for distance or time, accessible routing considers factors such as kerb heights, stairs, surface…

Adaptive Navigation(also: Adaptive Navigation Support)

A technique in which a system dynamically modifies the presentation of navigational elements (such as links, menus, or breadcrumbs) based on user characteristics, behaviour, or context. In accessibility applications, adaptive navigation can reorder, annotate, hide, or highlight…

Assistive Drone(also: Assistive UAV, Assistive Quadcopter)

A small unmanned aerial vehicle configured to assist a person with a disability — most often a blind or low-vision user — with tasks such as locating objects, navigating unfamiliar environments, scanning distant signage, and previewing walking-path conditions. Compared to…

Audible Pedestrian Signal(also: APS, Accessible Pedestrian Signal)

A device attached to a pedestrian crossing traffic signal that conveys the WALK and DON'T WALK phases through non-visual cues — typically beeps, chirps, speech messages, or a vibrating tactile arrow indicating the direction of travel. APS support safe crossing for blind and…

Audio Beacon(also: Auditory Beacon, Sound Beacon)

A spatial audio cue, typically a repeating tone or beep, attached to a specific location or object to help users with visual impairments navigate toward or identify points of interest in physical or virtual environments. Audio beacons vary in parameters such as pitch, timbre,…

Audio-Based Navigation(also: Audio Navigation, Auditory Navigation)

A navigation approach that uses audio output — typically synthesised speech, spatial audio cues, or sonification — as the primary means of providing wayfinding information to users. Audio-based navigation systems are particularly important for blind and visually impaired people,…

Auditory Map(also: Audio Map, Sonic Map)

An auditory map is an audio-based representation of geographical information designed to enable blind and visually impaired users to access and understand spatial environments without relying on vision. Auditory maps use combinations of speech, auditory icons (representative…

Aural Glancing

The auditory equivalent of visually glancing at a web page — the ability for screen reader users to quickly get a sense of what sections and content are available on a page without being forced to listen to every element serially. Aural glancing aims to bridge the fundamental…

Autonomous Navigation Robot(also: Autonomous guide robot, Self-navigating robot)

A mobile robot that plans and executes its own path through an environment to deliver a user or payload to a chosen destination, using onboard sensors (LiDAR, cameras, IMU) and a map for localisation, obstacle avoidance, and path planning. In accessibility contexts, autonomous…

BLE Beacon(also: Bluetooth Low Energy Beacon, iBeacon, Bluetooth Beacon)

A BLE (Bluetooth Low Energy) beacon is a small wireless transmitter that broadcasts a signal at regular intervals, which can be detected by nearby smartphones to determine a user's indoor location. In accessibility contexts, networks of BLE beacons are widely used to enable…

Blind Navigation(also: Non-visual navigation, Navigation for blind people)

The subfield of navigation research and assistive technology that addresses how people who are blind or have low vision find their way through indoor and outdoor environments without relying on sight. Solutions range from the white cane and guide dog to smartphone apps, BLE…

Bluetooth Beacons(also: BLE Beacons, iBeacons, Bluetooth Low Energy Beacons)

Small wireless transmitters that use Bluetooth Low Energy (BLE) to broadcast signals to nearby smartphones and other devices. In accessibility contexts, Bluetooth beacons are deployed in indoor environments to support wayfinding and navigation for blind and visually impaired…

Bluetooth beacon(also: BLE beacon, iBeacon)

A small wireless transmitter that uses Bluetooth Low Energy (BLE) to broadcast signals to nearby devices, enabling indoor positioning and proximity detection. In accessibility applications, beacon networks deployed throughout buildings allow navigation apps to determine a user's…

Bone Conduction(also: Bone Conduction Headphones, Bone Conduction Audio)

A method of transmitting sound vibrations through the bones of the skull directly to the inner ear, bypassing the outer and middle ear. Bone conduction headphones rest on the cheekbones or temples rather than covering or inserting into the ears, leaving the ear canals open to…

Breadcrumb(also: Breadcrumb Navigation, Breadcrumb Trail, Breadcrumbs)

A secondary navigation pattern that displays the user's current location within a site or application hierarchy as a series of linked steps, typically separated by arrows or slashes. Breadcrumbs help users understand where they are in a structure and navigate back to higher…

Built environment

The human-made surroundings that provide the setting for daily activity, encompassing buildings, streets, sidewalks, parks, transit systems, and all other constructed infrastructure. In accessibility, the built environment is a primary source of disabling barriers — missing curb…

Cell Navigation(also: Table Cell Navigation, Cell-by-Cell Navigation)

Cell navigation is a method of accessing tabular data non-visually by moving between individual cells using directional commands (up, down, left, right). Rather than reading a table linearly from top-to-bottom, cell navigation allows screen reader users to traverse the…

Clock Technique(also: Clock Method, Clock Face Direction System)

An orientation method used in mobility training for blind and visually impaired people in which directions are communicated using the positions on an analogue clock face. The user imagines standing at the centre of a clock with 12 o'clock directly ahead, 3 o'clock to the right,…

Cognitive Map(also: Cognitive Mapping)

An internal mental representation of spatial relationships within an environment, formed through direct experience, exploration, or learning from maps and descriptions. Cognitive maps allow people to understand where they are relative to other locations, plan routes, and orient…

Collision Prediction(also: Collision risk prediction, Trajectory prediction)

The task of estimating the future trajectories of surrounding pedestrians and obstacles and determining whether any of them will intersect with a user's own future position within a short prediction horizon (typically 2–4 seconds). In assistive technology for blind travellers,…

Community Navigation(also: Community Travel, Community Mobility)

The ability to plan, initiate, and complete trips within one's community, including getting to transit points on time, using public transportation, and accessing services at destinations. For people with cognitive disabilities such as traumatic brain injury, community navigation…

Crosswalk(also: Pedestrian Crossing, Zebra Crossing, Continental Crossing)

A marked area on a roadway designated for pedestrians to cross safely, typically indicated by painted lines or patterns on the pavement. Zebra crossings (called "continental crossings" in the US) feature bold parallel white stripes that are highly visible to drivers, while…

Crosswalk detection(also: Pedestrian crossing detection, Zebra crossing detection)

The automated identification and localization of marked pedestrian crossings in imagery using computer vision techniques. Crosswalk detection can be performed on satellite images, street-level photographs, or real-time camera feeds to populate navigation databases for blind…

Crowdsourced Accessibility Mapping(also: Collaborative Accessibility Mapping, Citizen-Sourced Accessibility Data)

The practice of using contributions from members of the public to identify, report, and map accessibility barriers and features in physical or digital environments. In urban contexts, crowdsourced accessibility mapping typically involves mobile applications that allow citizens…

Curb cut(also: Curb ramp, Dropped kerb, Pram ramp)

A small ramp built into the curb of a sidewalk at intersections and pedestrian crossings, providing a smooth transition between the sidewalk and the street. Originally mandated for wheelchair users under disability rights legislation such as the ADA, curb cuts have become a…

Dead Reckoning(also: Inertial Navigation, Pedestrian Dead Reckoning, PDR)

Dead reckoning is a navigation technique that estimates a user's current position by tracking their movement from a known starting point, using data from inertial sensors such as accelerometers and gyroscopes. In accessible wayfinding applications for blind and low-vision users,…

Digital Compass(also: Electronic Compass, Magnetometer)

An electronic sensor that detects the Earth's magnetic field to determine the direction a person or device is facing, providing heading information in degrees or cardinal directions. In assistive technology for blind and visually impaired users, digital compasses are integrated…

Directional Guidance(also: Navigation Guidance, Orientation Feedback)

Real-time feedback that helps users maintain correct positioning or navigate toward a target, commonly provided through audio cues (such as pitch changes) or haptic signals (such as vibration patterns). In accessible reading systems, directional guidance indicates when a user…

Echolocation(also: Human echolocation, Active echolocation)

The ability to determine the location and characteristics of objects by emitting sounds and interpreting their echoes. While commonly associated with bats and dolphins, many blind and low-vision individuals develop echolocation skills for spatial navigation, using self-generated…

Electronic Travel Aid(also: ETA)

An electronic device designed to help blind or visually impaired people navigate their environment by detecting obstacles and conveying spatial information through non-visual feedback such as audio cues, vibrations, or tactile signals. Electronic travel aids range from simple…

Environmental Flow(also: Optic Flow, Sensory Flow)

The ordered changes in a pedestrian's distances and directions to surrounding objects that occur while walking, providing continuous feedback about spatial position and movement through the environment. For sighted people, environmental flow is primarily visual (optic flow), but…

Environmental Legibility(also: Legibility of the Environment, Spatial Legibility)

The ease with which people can perceive, understand, and form mental maps of a physical environment in order to orient themselves and navigate through it. Coined by urban planner Kevin Lynch, legibility refers to the visual clarity of a cityscape or built environment — how…

Floor Plan(also: Floor Map, Building Plan, Building Layout)

A floor plan is a scaled diagram of a room or building viewed from above, showing the arrangement of rooms, corridors, exits, and other spatial features. In accessibility contexts, floor plans present significant challenges for people with visual impairments because they are…

GPS(also: Global Positioning System, GNSS, Satellite Navigation)

The Global Positioning System (GPS) is a satellite-based navigation system that provides location and time information to receivers on Earth. For accessibility, GPS is foundational to wayfinding apps used by blind and low-vision travelers, enabling turn-by-turn navigation and…

Gait analysis(also: Walking pattern analysis, Locomotion analysis)

The systematic study of human walking patterns, including step frequency, stride length, body sway, and turning behaviour, using sensors or observation. In accessibility research, gait analysis reveals that blind people who use white canes or guide dogs have distinct walking…

Geographic Information System(also: GIS)

A system for capturing, storing, analyzing, and displaying geographically referenced spatial data. In accessibility, GIS technology underpins navigation and wayfinding tools for blind and visually impaired users by providing detailed environmental databases that can be queried…

Global Navigation(also: Macro navigation, Route-scale navigation)

Navigation at the scale of routes and buildings — delivering a user from a starting point to a general destination area (a room, a platform, an exit). In blind-navigation research, global-navigation systems are typically turn-by-turn, localised via GPS, BLE beacons, Wi-Fi RSS,…

GoodMaps

GoodMaps is an accessible indoor navigation platform that provides detailed indoor maps and turn-by-turn navigation for blind and low-vision users in buildings such as airports, transit stations, hospitals, and government offices. The system uses a combination of smartphone…

Hamburger Menu(also: Hamburger Icon, Menu Icon)

A UI pattern using three stacked horizontal lines (☰) to hide and reveal a primary navigation menu, most commonly on mobile interfaces. Accessibility considerations include the need for an accessible name (e.g., aria-label="Menu"), keyboard operability, proper focus management…

Indoor Navigation(also: Indoor Wayfinding, Indoor Positioning)

Technologies and systems that help users find their way within indoor environments such as museums, shopping centers, airports, and public buildings where GPS signals are unreliable. Indoor navigation systems for blind and low vision users may use Bluetooth beacons, Wi-Fi…

Indoor Positioning System(also: IPS)

A technology system that determines the location of people or objects inside buildings where GPS signals are unavailable or unreliable. Indoor positioning systems use various technologies including Wi-Fi fingerprinting, Bluetooth Low Energy (BLE) beacons, ultra-wideband (UWB),…

Inertial Sensing(also: IMU sensing, Inertial measurement)

The use of accelerometers, gyroscopes, and magnetometers — often built into smartphones and wearable devices — to measure motion, orientation, and direction of movement. In accessibility applications, inertial sensing enables dead reckoning for indoor navigation where GPS is…

Inertial Sensors(also: IMU, Inertial Measurement Unit)

Electronic sensors that measure motion and orientation, typically including accelerometers (measuring acceleration/tilt), gyroscopes (measuring rotation), and magnetometers (measuring magnetic field/compass heading). In accessibility applications, inertial sensors enable indoor…

Landmark(also: Navigation Landmark, Environmental Landmark)

A distinctive environmental feature used as a reference point during navigation and wayfinding. In Orientation and Mobility training for people with visual impairments, landmarks are categorized by the sense used to detect them: structural landmarks (doors, stairs, elevators)…

Landmark Object(also: Navigation landmark, Target object)

A specific physical object that serves as the terminal target of a navigation task — for example, an empty chair in a waiting area, a push-button at an elevator, a ticket barrier, a door handle, or a counter at a shop. For blind travellers, landmark objects are the object of…