Introduction

This document provides useful installation guidelines regarding how to properly deploy and install a Wirepas Massive Tracking system.

The targeted audience is integrators and installers, but this document is also valuable for everyone wishing to better understand how to properly dimension a Wirepas Massive Tracking system.

What you’ll learn

• What the steps are to deploy a Wirepas Massive Tracking system.
• How to properly place the anchors and the gateways.

What you’ll need

• An understanding of Wirepas Massive Tracking system and its components, therefore, please read Wirepas Positioning System Overview [1]
• A good understanding of the dimensioning of the system (i.e. how many anchors and gateways are required for your site depending on the total area to be covered and the number of tags and their reporting frequency). Please refer to the Wirepas Positioning Dimensioning guide [2] for more details.

A few reminders about Wirepas Massive Tracking and Wirepas Massive: 

A Wirepas Massive Tracking system consists of the following elements: [1]

• Anchors

These are Wirepas Massive routers which serve as a location reference for the Wirepas Positioning Engine (WPE) and are also used to route data from the Asset Tags to the Gateways and from the Gateways to the Asset Tags. 

Anchors are most of the time battery-operated and have a battery lifetime of 5+years (depending on battery capacity). 

• Gateway(s): 

The Gateway(s) collect(s) the data coming from the Asset Tags through the Wirepas Massive network and send it to a server (On-Cloud or On-Premise). Gateways can also receive commands and/or software update messages (OTAP) from the server to be sent to individual Asset Tags or to the whole network. 

• Asset Tags:

The Asset Tags are Wirepas nodes running the Wirepas positioning application. On a regular interval 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 Gateway(s) through the Wirepas Massive network. The Gateways then forward the measurement data to the server where the Wirepas Positioning Engine (WPE) runs and computes a position based on known position of Anchors and measured RSSI.

The picture below shows a few examples of Asset Tags from Wirepas Partners. Please visit http://www.wirepas.com/partner-products for the complete list.

Installation Guidelines

The next sections cover the installation guidelines, namely:

Step 1: Determine the initial numbers of Gateway(s) and Anchors.

Step 2: Determine the Gateway(s) and Anchor location.

Step 3: Install Gateway(s), Anchors and Tags.

Step 1: Determine the initial numbers of Gateway(s) and Anchors

Prior to the installation a proper dimensioning is required to ensure the network will be working properly. Even if Wirepas Massive is able to deal with many local challenges it is important to ensure the planning is optimal in order to ensure optimal power consumption of the infrastructure and high reliability for the network.

Wirepas provides a Wirepas Positioning Dimensioning guide [2] to help dimensioning the system in a typical environment. In case your project has some specificities please contact your Wirepas Support contact for any questions you may have.

Step 2: Determine the Gateway(s) and Anchors location 

Gateway location requirements

In this section we will define the optimal Gateway(s) and Anchors location. The locations depends on two main parameters: (1) Site topology (number of floors, area to cover etc.) and (2) Asset Tag density.

• Central position: A gateway should be physically located in a central position in order to limit the maximum number of hops within the mesh network as shown in the picture below.

• Line-of-Sight: Each gateway should see as many direct anchors as possible (note: one gateway can host a maximum of 14 connected nodes).
• Multi-Floor: In case of a Multi-Floor building it is recommended to have a minimum of one Gateway per floor.
• Area covered: A good rule-of-thumb is that one gateway shall cover a maximum of 30000m² in a typical project. The picture below gives an example of a proper Gateway location :

In case of an area with a high Asset Tag density (for example a storage area) it is useful to add a specific Gateway for that zone to avoid the sink overloading. Please refer to the Wirepas Positioning Dimensioning guide [2] for more details.

Anchors location requirements

The initial planning is often done off-site by analyzing the floorplan. Adjustments can then be done in the field as required (e.g. due to physical installation constraints the initial deployment plan may need to be adjusted).

Selecting the optimal Anchor position can be done through a few simple rules:

• Anchors around: To reach a good positioning accuracy an Asset Tag must be surrounded by more than 3 anchors (the Asset Tag should not have anchors only on one side). Typically a grid like deployment will fulfill this requirement. It is important to note that the Wirepas Positioning Engine (WPE) computes the Asset Tag position only inside the area consisting of the largest polygon build around Anchors, i.e. Assets tags won’t be localized outside of of the largest polygon drawn by the border anchors. 

However, in the case of a per-room location accuracy, one anchor in the center of each room will be enough. It won’t be possible to determine the exact position of the tag in the room but it will be enough to tell with a good accuracy if the tag is in the room or not (provided each room is equipped with an anchor). 

• Line-of-Sight: Anchors shall be installed such that any Asset Tag in the area covered by the Anchor has Line-of-Sight to the anchor. i.e. each anchor must have an unobstructed view to the area served.
• Distance between neighbor anchors: The distance between the anchors will impact the position accuracy. Typically 10-15m anchor spacing (with a height delta below 3m) is recommended to achieve position accuracy below 5m. It is important to note that Anchors must have a good connection between them to ensure a proper network operation. For this reason the maximum recommended distance between Anchors is 25m. 
• Anchor installation altitude:
  • The anchors shall be placed at a similar altitude. 
  • To get best accuracy it is recommended to place Anchors at a similar altitude or a bit higher compared to the Asset Tags to ensure measurement accuracy. In case of high ceiling environment it is recommend to place anchors on pillars or wall rather than ceilings. 
  • Anchors shall not be placed on the floor as it significantly impacts the RSSI measurements quality leading to bad network performance and poor positioning accuracy. 
• Anchor antenna radiation pattern: For best results the Anchor and Asset Tag antenna radiation pattern shall be omnidirectional (please consult the hardware manufacturer regarding the antenna radiation pattern). In case the antenna radiation pattern is not omnidirectional/uniform then the Anchor shall be oriented such that the non-uniform side will point away from the target area.
• Anchor hardware types: It is recommended to use the same Anchors devices in a project. In case of different Anchors providers then it is recommended to measure the RSSI difference between the two types. When there is a consistent difference between the two types the offset must be added to the WPE anchor configuration. This positioning RSSI offset can be set in WNT client under Settings → Node management tab. 
• Metallic surfaces: Installing the Anchors on large metallic surfaces will affect the antenna radiation pattern (as the effect is hardware specific please follow the hardware manufacturer recommendation).
  e.g. in some cases better results are obtained by installing the anchor on a non-metallic bracket away from a metallic pillar rather than directly on the large metallic pillar.
• Room level accuracy: In case a room level accuracy is required it is recommended to place one Anchor per room with the Anchor being placed at the center of the room (for very large rooms several anchors might be required). A similar strategy can be used if the Asset Tag should be reliably identified when they are inside a defined area.
• Multi-Floor: In multi-floor deployments the planning is done individually per floor. For areas where there is an open space spanning two or more floors then the Anchor placement shall be done such that it is less likely that Anchors from one floor are received with higher RSSI on the other floor(s). This can be achieved by placing the Anchors inside the floor instead of at the edge of the open area.

Deployment examples

In this section two examples are provided to illustrate the recommendations listed previously: 

• Case 1: per-room localization is a typical building environment
• Case 2: open environment (e.g. in industrial site) where area localization is requested.

Case 1: Per-room localization

To ensure a per-room accuracy (typically in a building) at least one anchor per room is needed. 

In case of a large room then several Anchors might be needed. It is recommended to place the Anchors at the center of the room typically on the ceiling (2.5m to 3.5m height). This is to ensure the maximal RSSI difference between rooms (due to the distance and wall attenuation) to avoid any location jump from one room to the other.

Case 2: Area localization

In this second use case we consider a typical industrial environment where the requirement is mainly to provide an Asset Tag position with a few meters accuracy. The goal is to know in which area the Asset Tag is located. The Anchors are typically deployed in grid separated by 10-15 meters, depending on the needed accuracy. 

The hall can then be split into areas that can be defined on Wirepas Network Tool (WNT) floorplans, as explained in the Wirepas Network Tool user guide [3]. The Wirepas Positioning Engine (WPE) embeds the area match and can give information on whether the Asset Tag is in one area or another. 

Step 3: Install Gateway(s), Anchors and Tags

Here are some guidelines regarding best practices to install Gateway(s) and Anchors onsite. As the system is formed around Gateway(s) the following steps are recommended to follow for a correct installation:

Step 1: Install and configure Gateway(s).

Step 2: Install Anchors starting from the Gateway(s) and extending to the complete site.

Gateway installation guidelines

Gateway(s) are in most cases the only mains-powered device(s). As seen earlier, the power source shall be provided at the optimal location. 

The Gateway configuration and installation guidelines are provided by the Gateway vendor. 

From a Wirepas Positioning system standpoint the important parameters to configure in the Gateway(s) are:

• Wirepas Massive Network to match the Asset Tags and Anchors.
• Wirepas Backend server address: Server address, Login and Password for the MQTT broker to match your server parameters.
• Other Gateway specific parameters like Cellular, Ethernet depending on Gateway vendors.

Anchors installation guidelines

Anchors shall be installed ideally starting from the Gateway(s) in order to ensure a proper connection (typically as seen in the WNT client). 

Anchors installation requires two main steps:

• Anchor activation and configuration. Anchors shall be activated and configured upon the Anchor vendor recommendation / specifications. From a Wirepas Massive Tracking point of view Anchors shall be:
  • Configured as Anchor nodes.
  • Configure the Wirepas Massive Network parameters to match the Asset Tags and Gateway
  • Configured in the selected Device class (usually one class is reserved for Anchors)
  • Turned on so they become visible in the network.
• Anchor commissioning and installation
  • Anchors shall be then installed following the guidelines described in previous chapter.
  • Anchors shall then be commissioned in the Wirepas Positioning Engine with correct position. This can be done either via the Wirepas Backend API or using the Wirepas Network Tool client.

Tags installation guidelines

Tags are usually installed after the complete infrastructure installation. As for Anchors 2 main steps are required:

• Tags Activation. Like Anchors, Tags shall be activated and configured upon the Tag vendor recommendation / specifications. From a Wirepas Massive Tracking point of view Tags shall be:
  • Configured as a Tag.
  • Configure the Wirepas Massive Network parameters to match the Anchors and Gateway
  • Configured to the selected device class (usually one class per device type or per family of tags)
  • Turned on so they become visible in the network.
• Tags commissioning and installation
  • Tags shall be then installed on the physical asset to be tracked.
  • For the tags to be seen in WNT Client, they should be drag and dropped on a floorplan as explained in the “How to place Anchors and Tags in a Building Floorplan” [4] document. From a Wirepas Backend standpoint nothing more has to be configured, computed Tag position shall then be visible on the API or in the WNT Client. 

Summary of guidelines for a Wirepas positioning system

• Wirepas Massive offers predictable performance and it is easy to dimension the network for a given use case.
• Gateway placement is important to achieve the best reliability and optimal power consumption of the anchors.
• There should be enough anchors around every gateway to balance the network load and improve resilience (10 anchors in radio range of every gateway is a good rule-of-thumb).
• Anchors should not be placed higher than 3m above the Asset Tags (not on high ceilings). All anchors should be approximately at the same height.

References:

[1] Wirepas Positioning system Overview
[2] Wirepas Positioning Dimensioning guide
[3] Wirepas Network Tool v4 - Building Floorplans

[4] How to place anchors and Tags on a building floorplan

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