What is Indoor Positioning in Warehouses? Thorough Explanation of Benefits and the Latest Technologies

Table of Contents

• What indoor positioning in warehouses is

• Benefits of implementing indoor positioning in warehouses

• Main technologies used for indoor positioning inside warehouses - Positioning using BLE beacons and Wi‑Fi - Positioning using UWB (ultra-wideband) - Positioning using RFID tags - Positioning using ultrasound - Self-localization using cameras, LiDAR, and IMU - Application of RTK technology (LRTK)

• Simple surveying with LRTK

• FAQ

What indoor positioning in warehouses is

Indoor positioning is the technology for determining the “location” of people and items in indoor spaces such as warehouses. GPS (Global Positioning System), which is commonly used in car navigation and smartphone map apps, suffers large accuracy degradation indoors because satellite signals have difficulty penetrating buildings, making it hard to determine precise positions inside a warehouse. Therefore, specialized technologies that can obtain location information of people and goods inside warehouses are required. These technologies are known as indoor positioning, sometimes called “indoor GPS” or “real-time locating systems (RTLS).” As logistics warehouses and factories advance digital transformation (DX), there is growing demand to visualize on-site movements with indoor positioning to improve productivity and safety.

Benefits of implementing indoor positioning in warehouses

Installing an indoor positioning system in a large warehouse yields various benefits. The main advantages are listed below.

• Efficient inventory management: By managing where products and materials are stored using location information, time spent searching for items can be reduced. For picking operations, workers can be guided to the item’s location or shown an optimal route, reducing unnecessary movement and directly shortening task time.

• Visualization and improvement of workflows: The movement paths of workers and forklifts can be recorded as location data to analyze frequently used routes and congestion points. This enables layout changes and route optimization to reduce wasted movement and supports productivity-improving kaizen.

• Improved safety management: Real-time awareness of hazardous areas and forklift routes can help prevent collisions with workers. Systems that issue warnings when a person enters a specific area can be implemented using indoor positioning data. Safety countermeasures based on location information can reduce the risk of workplace accidents.

• Labor saving and automation of operations: Location information is essential for automation technologies like AGVs (automated guided vehicles) and drone-based inventory management. Establishing indoor positioning infrastructure promotes the use of autonomous mobile robots, leading to labor savings. It also facilitates human-assist solutions, such as displaying guidance information in a worker’s view via AR glasses.

• Support for precision work: When high positioning accuracy is available, tasks that require precise placement of equipment or shelves according to layout can be performed reliably. During layout changes, equipment and shelving can be placed using accurate coordinates, preventing installation errors and reducing rework.

By leveraging indoor positioning in warehouses, a wide range of effects can be expected—from inventory control and safety measures to efficiency improvements and automation. Knowing “where people and things are” in real time will greatly evolve on-site management methods.

Main technologies used for indoor positioning inside warehouses

There are various technologies to realize indoor positioning. Below are representative methods commonly used in warehouses and their characteristics.

• Positioning using BLE beacons and Wi‑Fi: This method uses signals from Bluetooth Low Energy (BLE) beacons or Wi‑Fi access points. Multiple transmitters (beacons or wireless LAN routers) are installed in the warehouse, and a smartphone or dedicated terminal estimates distance from received signal strength or time of arrival to calculate position. It can leverage existing Wi‑Fi infrastructure, and BLE beacons are inexpensive and easy to install, so the barrier to adoption is low. However, accuracy tends to remain on the order of several meters (several ft), and reflections/interference from metal shelving can cause errors.

• Positioning using UWB (ultra-wideband): This method uses ultra-wideband radio called UWB. By transmitting and receiving extremely short radio pulses on the order of nanoseconds, distances can be measured with high precision. Multiple UWB anchors (fixed stations) are installed in the warehouse, and trilateration with tags attached to goods or vehicles enables high-precision positioning with errors on the order of 10–30 cm (3.9–11.8 in). UWB is gaining attention in factories and logistics and is being increasingly adopted, but dedicated hardware costs and initial setup effort are substantial, so covering a large warehouse can require significant investment.

• Positioning using RFID tags: This method reads RFID tags attached to items or pallets by radio to determine their presence. RFID readers are placed on shelves or at gates in the warehouse, and the area where a tag is read is automatically recorded to indicate “where that item is.” It is suitable for automatically detecting item removal/return or understanding inventory distribution by area. However, it does not identify exact coordinates and generally provides coarse location information such as “which shelf” or “which zone.”

• Positioning using ultrasound: This method uses ultrasound, a type of sound wave. Transmitters installed on the ceiling emit ultrasound, and position is inferred from time differences until the ultrasound reaches sensors. Compared to radio waves, ultrasound is less affected by walls or shelving, and 3D positioning (including height) is possible within the audible range. Some products claim accuracy on the order of a few centimeters (a few in), but installation and preliminary calibration are required, making it labor-intensive to deploy across a wide warehouse.

• Self-localization using cameras, LiDAR, and IMU: The moving unit itself determines its position from camera images, laser scanner (LiDAR) data, and inertial sensor (IMU) information. This applies SLAM (simultaneous localization and mapping) techniques developed in robotics: for example, a forklift or autonomous mobile robot equipped with LiDAR scans the surroundings and updates a map and its current position. Camera-only methods can recognize markers or distinctive patterns on floors and walls to determine the current position. These visual methods can achieve high accuracy without relying on radio infrastructure, but they require high-performance equipment and computing for image processing and may require prior creation and registration of an indoor map, which can be a deployment obstacle. Overhead camera systems can also track people and vehicles, but their coverage is limited when shelves block the view.

• Application of RTK technology (LRTK): As an approach different from the radio/sensor methods above, there are attempts to bring high-precision satellite positioning techniques used outdoors into indoor environments. RTK (real-time kinematic) corrects satellite positioning (GPS, etc.) errors to achieve centimeter-level positioning and has been used outdoors for surveying, agriculture, and autonomous driving. Combining RTK with a compact device and a smartphone and applying it to indoor positioning yields the latest solution called LRTK. First, a high-precision position is obtained by RTK outside the building or near a window; keeping that state, the device is taken indoors, and the smartphone’s built-in AR (augmented reality) functions and IMU sensors track movement while inside. Even where satellite signals cannot be received indoors, by integrating relative movement from the last high-precision reference position, centimeter-level accuracy can be maintained for short periods. This method allows high-precision positioning to be used easily only when needed without installing complex fixed infrastructure, significantly reducing cost and effort compared to conventional approaches.

As shown above, there are various technology options for indoor positioning in warehouses. Each differs in accuracy, required equipment, and cost, so it is important to choose the optimal method based on intended use and required accuracy level. For example, if rough location awareness of people or items is sufficient despite larger errors, inexpensive beacons may be enough; if you want real-time tracking of a forklift with accuracy better than 10 cm, high-precision methods such as UWB or LRTK are more appropriate.

Simple surveying with LRTK

As mentioned above, the latest indoor positioning solution that leverages RTK technology is called LRTK. LRTK consists of a palm-sized high-precision positioning device and a smartphone app, designed so anyone can easily perform centimeter-precision positioning and surveying. This makes tasks that previously required specialized surveying instruments or technicians feasible for on-site staff without extensive preparation.

How LRTK works: First, the current position is measured outdoors using RTK to obtain a high-precision reference coordinate. Keeping that state, you carry the device and smartphone into the warehouse; the smartphone’s AR features and gyroscope capture movement and continuously track position indoors. In short, LRTK treats the smartphone as a high-performance pedestrian navigation device while entering an area where satellites cannot be received, incrementally computing relative position from the last accurate fix. This allows point positioning and surveying to maintain accuracy on the order of a few centimeters for short times and distances. If prolonged or large movements cause accuracy concerns, re-measuring briefly at a location with satellite visibility resets the reference and restores high accuracy.

LRTK use cases: High-precision indoor positioning with a smartphone and LRTK is useful across many warehouse tasks. For example, for equipment layout changes, LRTK can measure installation coordinates on the floor to the centimeter and place machines or shelves exactly according to drawings. Precise layout work that used to require marking or a surveyor’s positioning can be accurately performed by on-site staff. For inventory counting and picking support, pre-recording shelf and product locations as 3D coordinates allows a tablet to display the worker’s current position and the target inventory location in real time, guiding workers through the warehouse. This optimizes picking routes, reduces travel distance, and enables efficient outbound operations despite labor shortages. LRTK can also log movement paths: if staff carry a smartphone and LRTK and walk for a set time, their trajectories can be recorded with high accuracy for later analysis—identifying unnecessary back-and-forths or dwell times, verifying layout improvements, and more. It also supports safety management by accurately capturing forklift and human paths to reassess hazardous areas. For equipment inspections, photos taken during inspection can be automatically tagged with position (coordinates and orientation) and stored in the cloud. Later, these photos can be intuitively shared on a map or 3D model, making management far easier than hand-drawn notes on paper plans.

Using LRTK dramatically streamlines necessary measurement tasks in warehouses. Indoor positioning and surveying are increasingly becoming part of daily on-site work. Previously, achieving millimeter- to centimeter-level accuracy required expensive total stations or laser scanners and often external contractors. With LRTK’s simple surveying, on-site staff can complete necessary measurements in short time. Calling an external surveyor each time a layout changes incurs time and cost, but with an in-house LRTK, you can respond immediately. The device can be mounted on the tip of a pole for stable measurements, and the app automatically calculates height corrections, so no complicated settings are required. LRTK prioritizes simple, intuitive operation so even first-time users can perform surveys without confusion.

Effects of introducing LRTK: When on-site teams can freely perform surveys themselves, decision-making accelerates. You can immediately collect accurate data for layout change simulations or performance measurement of operational improvements, dramatically speeding up the PDCA cycle. The flexibility to re-measure as needed supports rapid response to change. There are also major cost advantages: after acquiring the device and a smartphone, there are no per-measurement recurring costs. You can reduce outsourced surveying fees and eliminate delays when you need to measure immediately. Initial investment is also much smaller compared to other indoor positioning systems that require extensive fixed infrastructure.

The changes LRTK brings to on-site operations are significant. By enabling everyone to work with precise location data, warehouse management itself will be upgraded. If you face issues like “we need to measure but can’t” or “location data is inaccurate,” consider the new option of smartphone × LRTK. It can be a powerful ally in improving your operations.

FAQ

Q. What is needed to implement an indoor positioning system? A. Typical indoor positioning systems require installing sensors or antennas inside the warehouse and equipping tracked people or goods with tags or terminals. For example, BLE beacon systems require beacon transmitters, and UWB systems require multiple fixed anchors and UWB tags. Software and network infrastructure are also needed to process data collected from these devices. Smaller spaces need fewer devices, but fully covering a warehouse involves considerable initial setup. In contrast, with LRTK, fixed infrastructure is unnecessary—only the LRTK device itself and a compatible smartphone (currently iOS devices) are required. The ease of starting operation without on-site construction is a major advantage of LRTK.

Q. How accurate is positioning inside a warehouse? A. Accuracy varies by method. Wi‑Fi and BLE beacons typically have errors of several meters (several ft), suitable for coarse awareness such as “a person is around that shelf.” UWB and ultrasound positioning can achieve around 10–30 cm (3.9–11.8 in) of accuracy depending on the environment, enabling high-precision real-time tracking. Positioning using LRTK can obtain coordinates for measured points with errors of a few centimeters or less. Note that warehouses contain many factors that cause positioning errors—metal shelving, machinery, etc.—so radio-based methods require environment-specific calibration and correction. LRTK fundamentally leverages satellite positioning accuracy, so the centimeter precision obtained in open areas can be maintained indoors for a limited time, and relative accuracy between measurement points is very high.

Q. What equipment and environment are required to use LRTK? A. Requirements are simple: the LRTK device itself and a smartphone (iPhone or iPad, etc.) that connects to it. Install the dedicated LRTK app on the smartphone and pair via Bluetooth to prepare. To start positioning, perform initial RTK positioning (reference setting) outdoors or near a window where satellite signals can be received. Then carry the smartphone and device into the warehouse and tap the app to record coordinates at desired points. There is no need to install base stations inside the warehouse or perform complicated pre-calibration. Unless the site is an extreme environment such as an underground warehouse with no access outside, you can typically start measuring shortly after arriving on site.

Q. Can LRTK really achieve centimeter-level positioning? Will accuracy degrade indoors? A. Yes—if operated properly, highly accurate positioning within roughly a few centimeters of error is achievable. If an RTK measurement outdoors has achieved a Fix solution and centimeter-level accuracy, entering the building immediately afterward does not cause large errors. Smartphone AR technology can maintain high self-position accuracy for short periods, allowing high-precision continuation indoors. Of course, if satellite reception is completely lost for a long time, errors will gradually accumulate, but even for long movements across a large warehouse, you can restore accuracy by briefly reacquiring satellites. In actual tests, measuring about 10 points showed that point-to-point variation (precision error) falls within a standard deviation of approximately 1–2 cm (0.4–0.8 in). By measuring a single point multiple tens of times and averaging, sub‑1 cm accuracy is attainable, making it sufficient for in-house layout measurements and equipment installation control.

Q. Is specialized knowledge required for introduction and operation? Can on-site staff use it? A. No specialized knowledge or certification is necessary. LRTK systems are designed with simple UIs and automated processing so that even users who are not highly skilled with machinery can operate them intuitively. Device mounting is not difficult—typically attaching the device to a pole and holding it level. During positioning, the app displays current accuracy (for example, RTK Fix status or number of satellites), so first-time users can easily understand the situation. Operation manuals and tutorials are provided, and support desks are available if needed. In practice, equipment staff with no surveying experience can perform basic measurements after a short lecture, so onsite adoption is straightforward.