Introduction
Most IndoorAtlas indoor positioning system deployments have BLE beacon infrastructure deployed. IndoorAtlas does not sell BLE beacons, but we provide tools and services to help planning a BLE deployment. The purpose of this guide is to provide the reader with information about why deploying BLE beacons is often needed, how they should be setup and various considerations to keep in mind when procuring beacons.
Technical background
IndoorAtlas uses sensor fusion algorithms to compute location estimates in an deployed area. The sensor fusion use multiple sensor modalities, including:
- 3D geomagnetic fields
- WiFi RSSI (Received Signal Strength)
- WiFi RTT (round-trip time) also called WiFi FTM (fine time measurements), part of 802.11mc standard
- BLE beacons
- Inertial navigation (motion of the smartphone); pedestrian dead reckoning
- Barometer
- GPS and other satellite based navigation technologies
- Visual inertial odometry in AR mode
The availability of various sensor modalities for positioning purposes depends on the sensors provided by a given smartphone, the deployment process, as well as what infrastructure is available at a location. Some sensor modalities are completely independent from each other, some require other sensors to work. For example the WiFi RSSI modality and algorithms are independent from everything else, and the same is true for BLE beacons.
We can further recognise two different phases to indoor positioning: first fix and tracking.
Fast first location fix
In order to provide a great end user experience, many deployments require the ability to compute the first location estimate (first fix) quickly, in a matter of seconds. This is achieved typically indoors with radio positioning algorithms. For IndoorAtlas this means the use WiFi and/or BLE beacon signals.
WiFi RSSI and RTT signal based sensor are only available on Android devices, as Apple has restricted the access of WiFi signal data to their proprietary software.
Due to the reasons mentioned above, most IndoorAtlas deployments use a light beacon infrastructure to support indoor positioning. Our workflow includes a beacon planner tool, which makes it easy to design a beacon deployment.
The geomagnetic positioning algorithms also constitute an independent positioning capability which is capable of computing the first location fix independently of radio signals. However, in larger deployments this can take some time and it also requires moving around in the space.
Tracking
Once the first location fix has been established, the full stack of sensor fusion is used. This greatly enhances the location accuracy. In particular the geomagnetic positioning algorithms are used to compute accurate indoor positioning estimates.
Planning a deployment
IndoorAtlas provides a tool called "beacon planner" in our web application. It enables one to find out high level parameters such as how many beacons are needed, how they roughly should be located and so on. It also has capabilities to design the deployment in a detailed way. The beacon planner is separately documented. Please see beacon planner documentation here.
BLE Beacon deployment choices
The introduction above discussed some of the reasons why BLE beacons are often used in an IndoorAtlas deployment. BLE beacons can be further divided into two different subcategories: battery operated beacons and beacons embedded in WiFi access points. Both types of beacons in principle work the same way from the IndoorAtlas point of view, and our software on the smartphone does not make a distinction on whether a beacon is a battery operated one or a beacon embedded in a WiFi access point.
Battery operated beacons
These are the lowest cost beacons. They are easy to install, often times with an included double sided tape or other adhesive. A battery operated beacon infrastructure is independent of any other radio infrastructure a venue may have, and thus from an organizational point of view typically easy to deploy.
WiFi infrastructure with BLE beacons
Recently the leading WiFi infrastructure providers have started to include BLE capabilities in their WiFi access points. For example nearly all access points from Aruba (for example the Aruba 600 series of access points) have this capability. Also many WiFi access points from Cisco Systems, Juniper Networks and others include BLE capabilities.
There are many benefits to beacons embedded in access points: they can typically be centrally managed, they run on mains power and thus are not susceptible for batteries running out, and they might already be in a venue, ready to be used, thus avoiding installation of any new infrastructure.
The downside is that depending on the manufacturer the enablement of the beacon capability may require extra software licenses, in some cases they can have significant cost depending on the vendor. Also some WiFi access points do not support simultaneous reception and transmission of BLE signals, they can only be configured to receive or transmit. For IndoorAtlas indoor positioning only transmission capability is needed. Problems will arise if for some reason the BLE capabilities of an access point are already used for something else in receive mode and the access point is limited to a single data transfer direction.
An operational challenge can be the enablement of BLE functionality even if it is available hardware wise.
Beacon parameters
Regardless of what type of beacons are being used, the beacons need to support iBeacon compatible protocols. The key parameters to configure are:
- UUID - should be the same for all beacons in a building
- major and minor numbers - need to be unique for a given UUID. Major number typically used to indicate the floor level of the beacon or some other helpful information.
- Transmission power - typically configured to -8 dBm. In order for the BLE signals to bring value to indoor positioninig, they need to be local to an area. If a beacon is too loud, for example transmitting at 0 dBm, the beacon signal can potentially be heard far away and therefore the signal does not tell much about the proximity of a beacon. The opposite is also true, if the signal level is too low, the signal may be lost.
- Advertisement interval - typically set to 300 ms or 500ms. This determines how often the beacon advertises its existence.
- Access control - this is vendor specific and it might a password or something else. Many beacons are configured with a smartphone app, and some form of access control needs to be in place to only allow the configuration of the beacons to be done by an authorized person.
Pre-configuration
When ordering beacons, it is normally possible to have the beacon parameters be preconfigured by the vendor. This typically requires an order of a minimum size, for example at least 100 beacons. Pre configuration is very useful as it saves time during deployment.
BLE beacon management & service
Once a beacon infrastructure is deployed, it may need management from time to time. This is especially true for battery powered beacons - they may run out of batteries, or may even be stolen.
Some beacon vendors provide specific fleet management tools. They typically have a rich feature set, but may come with significant extra license cost and extra hardware.
A beacon system deployed for IndoorAtlas does not require specific maintenance tools. IndoorAtlas provides as a service help to scan the health of beacon deployment. A deployment can be scanned by walking around the venue with a smartphone running running IndoorAtlas software configured in a suitable way to store the signal data into our cloud. IndoorAtlas can then analyze the received information and provide a report of the statusof the deployment.
BLE Beacon vendors
Below we list some beacons that some of our partners have used. This list is more of an example than anything else. There are mare beacon vendors, and since at IndoorAtlas we don't normally procure beacons for our customers' deployments, we only mention here a few example vendors and an example beacon. The vendors typically provide many different models of BLE beacons with varying capabilities.
Some beacon vendors also provide customization of beacons, for example the color of the case can be chosen and custom branding may be applied as well.