Introduction

This document gives an introduction to Wirepas positioning system, explains how it works and which building blocks it includes. 

The document first explains which tracking applications Wirepas Positioning system is well suited for. Then, it covers the different components provided by Wirepas to build a Smart Tracking system.

What you’ll learn

• Applications where Wirepas positioning system is a good fit
• Wirepas positioning system architecture and operation model
• Wirepas positioning terminology anchors, asset tags, gateway

What you’ll need

Even if it is not mandatory, you will preferably need a basic understanding of Wirepas Massive. For further information on Wirepas Massive, please refer to Wirepas Massive Concept document [1] 

Wirepas positioning product fit

This section provides an introduction explaining for which use cases Wirepas positioning system is a good fit.

Positioning systems introduction

There are many positioning technologies available on the market to track assets, people or goods. The various positioning systems have different performance and system cost points making them suitable for given use cases and not suitable for others. They can widely differ from one another in terms of:

• Total cost of ownership:
  • Infrastructure cost (Material and Installation)
  • Tags cost
• Performance
  • Location accuracy and real time reporting
  • Continuous vs one-time reporting 
  • Tags power consumption
  • Bidirectional communication with the assets or not
• How easy it is to install and provision the system
• How easy it is to update, modify or extend the system
• Reliability
  • Reliability in industrial environments
  • Capacity to support high density or not

Wirepas Positioning value proposition

Wirepas Positioning value proposition is described below:

• The location infrastructure is extremely low cost as it consists of Anchor nodes (Wirepas Massive routers) which can be battery operated with a very long battery life (>5years).
• The installation is extremely simple as:
  • it does not require extra wiring
  • it does not require complex planning - the installation mainly consists of placing anchors at fixed places in the building 
  • it does not require special equipment or specialized staff for installation and maintenance
• The asset Tags and Anchors are widely available from Wirepas partners in various form factors. They consist of tags with a BLE chip programmed with Wirepas positioning application and Wirepas Massive stack
• The positioning system easily covers the complete building (as opposed to RFID which is limited to specific zones) and the reporting frequency is programmable - a typical reporting period of 5 minutes is recommended for asset tags to have a battery lifetime of several years 
• The Wirepas system can also enable accurate and fast inventory of a high number of tags (~typically 6000 devices/ minute) - this mode is used for pallet inventory in service centers, fast inventory of goods in a container, goods in and out… 

Wirepas Massive is used as the network and brings the following benefits: 

• The system is extremely reliable in harsh industrial environments and is able to scale
• Every node can report its position but also its sensor data (temperature, motion, humidity…)
• Every node can receive commands from the network enabling control (switch On/Off and LED on an asset tag), configuration (change the reporting frequency or other parameters of the asset tag) and software updates (the infrastructure and the asset tag software can be regularly updated through Wirepas Massive OTAP)

Wirepas Positioning typical use cases

Wirepas positioning system is perfectly suited for smart tracking in large places where it is key to optimize the cost of infrastructure and its roll-out (as wiring becomes extremely costly) or where the system needs to be deployed without disturbing the site operations.
It is also a very good fit in industrial environments where the system needs to be reliable despite frequency interference or despite a complex radio environment (presence of metal, concrete …).
 Here are some example application use cases where Wirepas positioning is bringing significant value:

• Tools, assets, pallet, goods tracking and inventory in warehouses
• Production assets and Tools tracking
• Construction Tools and workers tracking
• Healthcare equipment, patients and personnel tracking. Elderly care applications
• Agriculture – livestock tracking and health monitoring

Wirepas Positioning Operation principle

Like most positioning systems, Wirepas Positioning relies on:

• Wirepas anchors and gateways: the hardware infrastructure which serves as reference for location and communication network.
• Wirepas asset Tags: the hardware tags attached to the moving objects to be tracked.
• Wirepas Backend: the central server consisting of:
  • A positioning solver which collects raw information coming from the tags and/or from the anchors and computes the physical location of the asset tag: Wirepas Positioning Engine
  • An installation tool to setup the infrastructure and commission the Anchors and Tags to the positioning service.

The end user application: because the application is specific to each and every use case (e.g: Healthcare, Construction, Manufacturing), Wirepas does not provide it. Wirepas customers develop their own end user application. 

The end-user application typically:

• Receives the positioning data from the Wirepas Positioning Backend
• Provides positions to a user interface which presents the location information inside a map, a building floor plan or table and provides capability to query the list of assets and get their position and various status information (battery level, connection status, sensor data …)

Wirepas anchors and gateways

The Wirepas positioning infrastructure consists of few gateways installed at locations where a power outlet is available, and battery operated anchors which are placed at regular positions within the building. Since the anchors can be battery operated, the installer has a lot of flexibility to place the anchors where suitable. The anchors serve as a location reference for the moving assets and are also used to route data from the asset tags to the gateways and from the gateways to the tags via Wirepas Massive network.

Once the system is powered up, a Wirepas Massive network automatically forms up and the system is ready to route data from and to the assets when they join the network.

No configuration is required for the network to operate (as long as all devices share the same Wirepas Massive network credentials – see more details below).

The illustration below presents the typical infrastructure where several gateways in different sites or area are usually connected to the backend.

Infrastructure Key components:

Anchors

These are Wirepas Massive routers which serve as a location reference for the Wirepas Positioning Engine and are also used to route data from the asset tags to the gateways and from the gateways to the tags. 

Anchors are most of the time battery operated and have a battery lifetime of 5+years (depending on battery capacity). Any Wirepas Massive router (not auto-role) can be an anchor in a Wirepas Positioning system allowing to reuse an existing infrastructure of devices as locator. e.g: in combination with Wirepas enabled Smart Lights.

The picture below presents a few examples of Anchors from Wirepas Partners. Please visit wirepas.com/partners for the complete list.

Wirepas Massive gateways: 

The gateway(s) collect(s) the data coming from the tags through the Wirepas Massive network and send it to a server (Cloud or On-Premise). Wirepas Massive gateways can also receive command, control, or software update messages from the server to be sent to individual tags or to the whole network. Any Wirepas Massive gateway compliant with Wirepas API between a Gateway and Wirepas Backends[2] can be used in a Wirepas Positioning system.

Asset Tags:

The asset tags are Wirepas Massive non-router nodes running Wirepas positioning application. On regular intervals or via locally triggered action (movement, button press…), the asset tags wake-up, collect signal strength information (RSSI) from the anchors in their neighborhood and send the information to the Wirepas gateways (through the Wirepas Massive network). The Wirepas gateways then forward the measurements data to the server where Wirepas Positioning runs and compute a position based on known position of Anchors and measured RSSI.

The picture below presents a few examples of Tags from Wirepas Partners. Please visit wirepas.com/partners for the complete list.

The software of the asset tags is optimized to allow very low power consumption. The reporting frequency is configurable and is typically in the range of few minutes to allow the asset tag to have several years of battery life. The reporting period and other parameters of the tag can be managed remotely from the network.

• The data is then retrieved by the Wirepas Positioning Engine (WPE) which computes the position of the asset based on the RSSI data and the position of each neighbor anchor of that asset. The position is then made available to the application in JSON format and can be used to draw the asset position on the floor plan or simply be fed to the IT system.
• Wirepas positioning system includes an example client application (Wirepas Network Tool client – WNT client) which includes floorplan management and an example user interface to install the anchors and visualize moving asset position on a floorplan. WNT client also provides information about the network health and battery levels in the asset tags. WNT can be used as an installation tool for the Wirepas anchors (as described below); the positioning UI should not be used in production.
• Wirepas Massive is a self-forming, self-healing mesh network and does not require any specific configuration by the user in a Wirepas positioning system. Network parameters are included in the tags, anchors and gateway software (or provided as part of the provisioning process) and allow the network to automatically form and operate.

Wirepas Backend

The backend is the server where all the gateways a connected to send and receive data. Wirepas Network Tool backend and Wirepas Positioning Engine are delivered as instances to be self-installed by customers in their own cloud infrastructure and are build around 3 main components:

• An MQTT Broker where all Gateways are connected.
• Wirepas Positioning Engine: The positioning solver
• Wirepas Network Tool Backend: To manage the configuration, monitoring and scheduling of the different dataflow in the server.

The figure below provides a description of the different blocks followed by a more detailed description.

MQTT Broker: The Wirepas Massive data is aggregated by the Wirepas gateways and sent to a central MQTT broker. Any cloud application having the MQTT broker credentials can join, publish and subscribe to the relevant MQTT topics to access sensor data, raw RSSI data or send specific control or configuration messages to the nodes. Positioning data is also available in the MQTT broker. 

Wirepas Network Tool backend: WNT backend is a service which runs in a server and is delivered as an instance to be installed by customers in their system (either on-premises or in the cloud). This service has the following functionality: 

• Collects network diagnostic messages sent by the nodes and exposes network information to the user (topology, list of connected nodes, connection status, battery levels…) - this allows (for example) the application to get all the information required on the connectivity status of the positioning infrastructure - gateways and anchors. 
  • Sends configuration messages to the nodes and gateway
  • Manages floorplans
  • Starts Wirepas Positioning Engine (WPE)  service
  • Sets anchors location and configures WPE
  • Retrieves node positions from WPE and exposes them via API. 
  • The features and API calls available in WNT backend are described in WNT backend API document [3]

Wirepas Positioning Engine: is the engine which computes the asset tag location from the RSSI information sent by the asset tag and the anchor position. 

• At initialization, it receives the anchor list and location information (typically from Wirepas Network Tool)
  • When Wirepas Positioning Engine is started, it consumes a stream of RSSI measurements coming from the asset tags and outputs a stream including the asset tag locations.

Wirepas Network Tool Client [4] is an optional Windows tool allowing to visualize the network topology, nodes diagnostics and position. Wirepas Network Tool client can be used during the installation phase to input floor plans and set the position of anchors on the floor plan [5].

Going further

You can evaluate Wirepas Positioning system using Wirepas Positioning kit. It can be purchased from our partner ELA Innovation 

For more information on Wirepas Positioning kit you can refer to its getting started manual [6] 

References

[1] Wirepas Massive Concepts

[2] API between a Gateway and Wirepas Backends

[3] WNT backend API

[4] Wirepas Network Tool Client User Guide 

[5] How to place anchors and tags on a building floorplan in WNT client 

[6] Wirepas Positioning Kit getting started manual 

Revision History

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