Selection criteria for indoor positioning systems
The following factors play a key role in the selection of an RTLS system:
Environmental stability
Under laboratory conditions, it’s always quite straightforward. However, things become more difficult when the environment changes in such a way that equipment and people are moving around within it, meaning the environment is constantly changing.
Purpose of the tracking
When it comes to protecting a person using a tracking system, different factors need to be taken into account than when minimising the effort involved in searching for items such as devices.
Accuracy requirements
Even though many manufacturers are keen to outdo one another in terms of pinpointing locations to the nearest millimetre, this is only truly relevant in a few cases.
A comparison of different positioning technologies
There are a wide variety of approaches to indoor positioning. Each solution has its own advantages and disadvantages, which means that, particularly when it comes to indoor tracking, there is no one-size-fits-all solution.
How it works:
Location tracking via Bluetooth by measuring signal strength via existing Bluetooth access points.
Advantage:
- Existing infrastructure with Bluetooth access points can be utilised.
Disadvantage:
- Access point manufacturers often charge high licence fees, and a very large number of access points are required.
- Bluetooth is completely shielded by the body and does not penetrate it.
- It is therefore not necessarily suitable as a purely indoor positioning solution
How it works: Battery-powered Bluetooth transmitters are mounted on the wall and transmit the location to the mobile device. This enables the mobile device to determine its own location and can also be used for indoor navigation.
Advantages:
- Cost-effective installation
Disadvantages:
- Batteries need to be replaced after a certain period of time → higher maintenance costs
- Higher energy consumption in mobile devices → The system’s usability depends entirely on energy management
- Take the smartphone as an example: the user charges the device regularly → it works
- Example: a wristband for patients: it is no longer possible to reliably ensure that the person recharges the devices
- Charging management by nursing staff is generally rejected, as it leads to extra work and significantly reduces the benefits of a simplified search process
How it works: Location tracking via Wi-Fi triangulation using Wi-Fi access points.
Advantage:
- Works in exactly the same way as Bluetooth Low Energy triangulation
- The signal does not pass through the body
Disadvantage:
- Works in exactly the same way as Bluetooth Low Energy triangulation
- The signal does not pass through the body
- To ensure good coverage, you need to install around three times as many access points in a building as are actually required for communication
- Access point manufacturers often charge high fees for licences to use location data
Advantages:
- Offers the ability to track with extreme precision, down to the millimetre
Disadvantages:
- The energy consumption of the device being tracked is relatively high
- Only a short battery life is to be expected
- Excludes solutions where staff would have to repeatedly recharge devices or replace batteries
- Alternative: Make the tracker large enough → this means that people can no longer be tracked, and larger devices cannot be tracked either
Advantage:
- You don’t need trackers on the devices
Disadvantages:
- This presupposes that you are in areas where it is accepted that cameras are filming everywhere
- This is certainly not the case in hospitals or care homes
- This assumes that the environment is relatively stable and is not subject to excessive shading
- Solution: Place small cameras or smartphones inside the building
- Devices to be tracked must not look too similar
- Tracking must be comprehensive
How it works: Passive RFID tags are detected by readers. As with active RFID technology, these can only be detected by local readers – this therefore also constitutes a proximity tracking approach.
Advantages:
- Size, in particular, is a factor: they can be made very small
- Very good value for money: can be used as a disposable product
Disadvantage:
- Tracking is only possible via local readers (proximity tracking)
How it works: Some customers use a method similar to Care2Graph, combining RFID and infrared technology. The mobile device either transmits an infrared signal or receives one from fixed devices in order to obtain information about its own location. As the infrared signal remains within the room, this enables positioning accurate to the room.
Advantages:
- Room-level localisation
- Energy consumption of mobile devices is relatively low
- Energy management does not result in excessive staff costs
Disadvantages:
- Technology that is not particularly widespread
- Excludes most smart devices
- Only these trackers can be located
- With Bluetooth, you can also locate phones and tablets using the relevant app
The Care2Graph solution from Martin.Care
Requirements in the healthcare sector
In hospitals, care homes, psychiatric wards, etc., location tracking is usually only required at the room level. Tracking to the nearest millimetre offers no significant added value for process optimisation. The most important piece of information is which room an asset or a patient is in.
At the same time, there is a need for many systems that can also track the location of smart devices, so that, for example:
- Care records can be supported by location data via a mobile device
- It is possible to navigate around the building using a smartphone
Combination of technologies
For this reason, the Martin.Care system uses:
1. Bluetooth proximity tracking as a basic tracking function
In this way, mobile devices act as beacons, and devices with a fixed power supply can be used for positioning.
2. Active RFID at critical points
- However, as Bluetooth is not particularly reliable due to its poor ability to penetrate physical barriers (such as water), the system also uses active RFID in places where, for example:
- A circuit should be triggered based on a position
- An alarm should be triggered based on a position
3. Sub-GHz frequency for communication
- To ensure that information about the location and the alert is transmitted reliably, a sub-GHz frequency is used
- It has better penetration than Wi-Fi or Bluetooth, yet can still be encrypted.
References
Over 2,500 systems installed in hospitals, care homes and psychiatric institutions
There are a wide variety of approaches to indoor positioning. Each solution has its own advantages and disadvantages, which means that, particularly when it comes to indoor tracking, there is no one-size-fits-all solution.
Decision-making guide
Anwendungsfall | Technologie Empfehlung | Begründung |
Weglaufschutz für Demenzkranke | Ortung: Aktives RFID Kommunikation: Sub-GHz | Zuverlässigkeit bei Körperabschattung |
Mobiler Schwesternruf mit Ortung | Ortung: Bluetooth Low Energy Kommunikation: Sub-GHz | Die Sub-GHz stellt die Zuverlässigkeit in der Rufübermittlung dar. Die Ortung kann über BLE erfolgen |
Personalnotruf mit Ortung | Ortung: Bluetooth Low Energy Kommunikation: Sub-GHz | |
Größere Medizingeräte | Ortung: Bluetooth Low Energy Kommunikation: Sub-GHz / Bluetooth | Geräte wie Betten lassen sich über BLE einfach Tracken. |
Diebstahlschutz für größere Medizingeräte | Ortung: Aktives RFID Kommunikation: Sub-GHz | Zuverlässigkeit bei der Alarmierung am Ausgang, da diese Geräte meist auch ein hoher Kostenfaktor in der Anschaffung sind. |
Kleine Medizingeräte | Ortung: Passives RFID Kommunikation: Passives RFID | |
Disposables und Kleidung | Ortung: Passives RFID Kommunikation: Passives RFID | Da es um Wegwerfartikel geht, welche nur einmal genutzt werden spielt der Preis des Tags die maßgebliche Rolle. |
Geräte welche mit Hitze desinfiziert werden | Ortung: Passives RFID Kommunikation: Passives RFID | Die meisten Akkus und Batterien haben eine Maximaltemperatur, welche zum Desinfizieren nicht ausreicht. Aus dem Grund ist eine Technologie ohne Batterie die beste Wahl. |
Decision-making guide
Anwendungsfall | Technologie Empfehlung | Begründung |
Weglaufschutz für Demenzkranke | Ortung: Aktives RFID Kommunikation: Sub-GHz | Zuverlässigkeit bei Körperabschattung |
Mobiler Schwesternruf mit Ortung | Ortung: Bluetooth Low Energy Kommunikation: Sub-GHz | Die Sub-GHz stellt die Zuverlässigkeit in der Rufübermittlung dar. Die Ortung kann über BLE erfolgen |
Personalnotruf mit Ortung | Ortung: Bluetooth Low Energy Kommunikation: Sub-GHz | |
Größere Medizingeräte | Ortung: Bluetooth Low Energy Kommunikation: Sub-GHz / Bluetooth | Geräte wie Betten lassen sich über BLE einfach Tracken. |
Diebstahlschutz für größere Medizingeräte | Ortung: Aktives RFID Kommunikation: Sub-GHz | Zuverlässigkeit bei der Alarmierung am Ausgang, da diese Geräte meist auch ein hoher Kostenfaktor in der Anschaffung sind. |
Kleine Medizingeräte | Ortung: Passives RFID Kommunikation: Passives RFID | |
Disposables und Kleidung | Ortung: Passives RFID Kommunikation: Passives RFID | Da es um Wegwerfartikel geht, welche nur einmal genutzt werden spielt der Preis des Tags die maßgebliche Rolle. |
Geräte welche mit Hitze desinfiziert werden | Ortung: Passives RFID Kommunikation: Passives RFID | Die meisten Akkus und Batterien haben eine Maximaltemperatur, welche zum Desinfizieren nicht ausreicht. Aus dem Grund ist eine Technologie ohne Batterie die beste Wahl. |
