Blog skyhook logo Using Wi-Fi for Indoor Positioning

Mar 31, 2020 4:13:00 PM

Using Wi-Fi for Indoor Positioning

Posted by Kipp Jones

Read All Posts

Did you know: since the launch of the original iPhone, every person with a smartphone has been using Wi-Fi signals to enhance his or her indoor positioning accuracy. What has changed since then is the level of accuracy that can be achieved with Wi-Fi indoor positioning. This increased focus on location accuracy is set to continue as our technology, standards and solutions evolve.
Precise indoor positioning systems and indoor location tracking is becoming more common in today's connected and digitized world. The indoor location based service market is predicted to reach a value of approximately 19 Billion by 2030 on a global lever. It is being implemented in places we might not expect and expands beyond just warehouses to airports, shopping malls, grocery stores and more. The use cases range from IoT monitoring and asset tracking to sending relevant marketing messages to nearby smartphones. Beyond all of these use cases are a reliance on accurate location as a key component of a robust indoor positioning system.
When we think of location, we may jump to thinking about GPS (or GNSS). GNSS (Global Navigation Satellite Systems) are incredible systems that have been around since the late 70s and are ideal for locating devices outdoors, getting down to ~5 meters in commercial devices. However, while GPS is great for providing location outdoors, its benefits are marginalized or even lost in any type of indoor environment like a building or warehouse. That’s where alternative location technologies such as Wi-Fi positioning come in. 

What is Wi-Fi Positioning?

Wi-Fi positioning is a positioning system that uses several techniques to locate a connected object or device. Wi-Fi location uses already existing infrastructure and Wi-Fi access points (APs) to calculate where a device is located. The device needs to be able to listen for the Wi-Fi AP but does not need to connect to it. By analyzing the signal strength of multiple Wi-Fi signaland knowing the location of those APs, Skyhook is able to determine the approximate location of the device
Wi-Fi has a short range, but the signal can extend up to 150 meters. The accuracy generally dependon how many APs are nearby and the environment in which they are deployed. The more APs in a given area and the more precisely their position is known, the more accurate the location will be. Wi-Fi can provide about 20m accuracy using existing crowd sourced Wi-Fi infrastructure with no calibration. However, through calibration, surveying and fine tuning, Wi-Fi can achieve 5-8 meter accuracy in indoor environments. 


Unlike other indoor positioning technology solutions like BLE beacons or RFID, Wi-Fi does not require additional hardware or infrastructure maintenance. Nearly all facilities already have Wi-Fi infrastructure installed, providing a base level of positioning capability without additional investment.  Hardware solutions that must be manually deployed can be costly and time consuming, especially if you have multiple facilities that require the capability. As a result, other technologies require a larger budget in both money and time in order to create an effective environment for indoor positioning. 
Wi-Fi is a global indoor positioning solution that can be scaled with little to no manual intervention. For instance, implementing Wi-Fi positioning in 25 warehouses compared to manually deploying BLE beacons or RFID in 25 warehouses saves a lot of time and resources. In addition, because Skyhook maintains a global map of over 5 billion Wi-Fi access points, your positioning system will work around the globe, indoors and outdoors.
While Wi-Fi positioning provides instant-on capabilities, businesses have several options to improve the accuracy based on the use case requirements. A simple survey to map the precise locations of all Wi-Fi APs within a facility will improve the positioning accuracy of the system. If further accuracy is required, the company has the option to deploy additional Wi-Fi access points within their facilities. While this does represent an additional expense, it does not require the customer to learn, deploy, and maintain yet another technology within their infrastructure. This can be accomplished as part of a general Wi-Fi infrastructure improvement project or by simply adding additional Wi-Fi access points in areas that require additional positional accuracy.
Another benefit to implementing Wi-Fi as an indoor positioning technology is that the accuracy will only improve as more infrastructure is built and newer technologies are developed and deployed. Wi-Fi round-trip timing (RTT), part of the IEEE 802.11 protocol, is an example of where things are heading. With Wi-Fi RTT, devices will be able to use time-of-flight (ToF) as opposed to measuring the signal strength to determine the distance from the AP. By doing this, Wi-Fi RTT enables devices to calculate the location within 1-3 meters. This technology is available today and has been supported since Android 9 was released, providing the capability to test and demonstrate the level of accuracy attainable. Although Wi-Fi RTT won’t be fully deployable until 2020, the current investment in Wi-Fi as a positioning technology will continue to increase in value over the years as the technology and the industry continues to innovate. 
Indoor & Outdoor Operability
Wi-Fi positioning is not just an excellent solution for locating ‘things’ indoors, it workin both indoor and outdoor environments as well. This is especially important in use cases that require things to be located inside a building and outside of it as well. Wi-Fi can also be augmented by combining it with other technologies such as GPS to provide a complete and accurate global indoor and outdoor positioning solution. 

The Bottom Line

When determining the best indoor positioning solution for your use case, it’s important to keep in mind your budget, the level of accuracy you need to achieve, and the amount of additional hardware and maintenance effort required to meet you use case. Wi-Fi positioning is a viable long-term solution because:
  1. It takes advantage of existing infrastructure, 
  2. It doesn't require additional infrastructure maintenance, 
  3. It is cost effective and can be scaled easily,
  4. It is low power,
  5. It works indoors and outdoors — globally,
  6. Wi-Fi positioning can be augmented to achieve the level of accuracy you need,
  7. The infrastructure and accuracy is only going to improve with new standards and technology, 
  8. It can be combined with other positioning technologies for flexible deployment, accuracy and power profiles.