While most of us are quite comfortable finding our way outdoors using the industry standard GPS, this solution is not functional indoors. So how do you go about finding your way indoors? When you move from the outdoor GPS environment into a building you can be guided using an app on your phone that is connected to an Indoor Positioning System (IPS).
Although IPS's do not have an industry standard like GPS does, there are a variety of technologies that can be used to help you find your way. This is achieved using the same real-time location recognition as a GPS navigation system in your car. The equivalent to this for the indoors is referred to as 'Blue Dot' wayfinding.
In this post, we will outline the different technologies being used to deploy a Real-Time Location System (RTLS) and achieve the Blue Dot experience indoors as well as outline the key advantages and disadvantages of each.
|Technology||Accuracy||Range||Power Supply||Battery Life||Cost Range|
|Bluetooth (BLE)||up to 2 meters||up to 75 meters||Can be battery powered or connected to electrical grid||High||Low-Medium
|Wi-Fi||up to 15 meters||up to 150 meters||Smartphone or battery powered||Medium||Low-Medium
|Radio-Frequency ID (RFID)||up to 10 centimeters||up to 150 meters||
|Inertial Measurements||1%||up to 20 meters||n/a||n/a||Medium-High
|Geomagnetic||up to 1 centimeter||up to 20 meters||n/a||n/a||Low-Medium
Beacons are tiny pieces of hardware which emit Bluetooth signals to phones. Beacons use BLE (Bluetooth Low Energy) to communicate with smartphones and let them know the distance they are away from a particular beacon. A large network of Beacons is required to provide the accuracy necessary for an IPS.
Advantages: The accuracy of Bluetooth Beacons is thought to be the most reliable and best compared to the alternatives. Also, depending on the desired use case, the business can configure the Beacon network to be more or less accurate through settings and the number of beacons installed.
Disadvantages: There is a substantial upfront hardware and installation cost associated with Bluetooth Beacons. Also, depending on the venue and their IT protocols, increased BLE network traffic may not be preferred.
Wi-Fi networks can be used to identify a user's general location. Similar to Beacons, the strength of the Wi-Fi signal is used to determine the distance a user is from a particular access point.
Advantages: Existing Wi-Fi networks, including private networks can be used. The user does not need to connect to a network to determine their location. Their location is determined by the strength of the signal being given off by the closest access point.
Disadvantages: Accuracy will vary depending on the number of access points installed. Most spaces do not have enough Wi-Fi access points installed to provide an accurate indoor positioning experience and prolonged latency time can increase the deviation of the users actual location.
Radio Frequency Identification (RFID)
RFID transponder tags contain an integrated circuit and antenna which are used to transmit data to a reader. The reader then converts the radio waves to a more usable form of data. In most cases, the tags are passive and have no individual power supply. Depending on the frequency range, the reader must be located within a radius of between a few inches to one yard from the RFID tag to be able to transmit data. Active RFID tags have their own individual battery, making them a bit more expensive and heavy, however, they have a significantly higher range of up to 10 meters.
Advantages: RFID can be helpful for simple use cases, and is often employed by the production and logistics sectors for asset tracking through production processes. RFID also allows for data, like expiration dates, to be saved to an object's attached RFID tag, which can be especially helpful for hospital and medication logistics.
Disadvantages: It does not allow automatic indoor positioning. Instead you must set predefined points with RFID readers which are triggered when the tagged object passes. For this reason, RFID is not very flexible or user friendly for indoor navigation and is not going to give you a navigational Blue Dot experience.
Geomagnetic navigation uses the magnetic sensor or compass built into a phone. It senses a magnetic force given off the earth and metal objects nearby to determine the user’s location.
Advantages: It’s cost efficient because there is no hardware cost. The only cost associated with it is fingerprinting an area.
Disadvantages: The geomagnetic field is constantly changing in a building. Any item with steel or iron that is near a user's phone can cause changes in the geomagnetic field which would cause the readings to be inaccurate. Other issues and challenges have been identified, such as the user needing to be in motion (not stationary) for their device to receive their real-time location.
An inertial navigation system is a system that uses motion and/or rotation (accelerometer/gyroscopes) sensors that are available in a phone. Unlike the other options, inertial navigation is calculated via dead reckoning. This is the process of calculating your current position by using a determined starting point and advancing that position based on estimated speeds, distance and/or direction*.
Advantages: It’s the most cost efficient of the options because it requires no hardware or fingerprinting.
Disadvantages: It cannot be used stand-alone due to the fact that the starting point must be determined through another indoor positioning method. Inertial measurements can only be determined where a user is relative to where they began.
Did you know that the average person spends 90% of their time indoors? Given this sheer amount of time coupled with the staggering growth in the absolute size of indoor spaces, it's no wonder that people are finding it more difficult to navigate while inside. Recognizing the issues and impact associated with people being lost indoors, venue owners in various industries such as corporate offices, retail and shopping malls, hospitals and healthcare facilities, and hospitality venues are now investing in technologies to improve indoor navigation for their patrons. There are many other use cases for Real-Time Location Systems beyond indoor wayfinding and navigation. Once a venue has invested in indoor positioning technologies, the possibilities extend to asset tracking, business intelligence, proximity messaging, and more.
Given the pros and cons of each of the Indoor Positioning System options, the decision of which technology to rely on will largely depend on various factors unique to your venue and your goals, and what use cases you'd like to implement.
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* Fun Fact: Dead reckoning was commonly used at sea where a ship would keep track of the speed, distance and direction it traveled from a set starting point to determine their location.
Updated October 18, 2018: This post was originally published on June 26, 2016 and has been updated to reflect the growing importance and availability of positioning techniques and technologies to enable Blue Dot experiences indoors.