Indoor Positioning with WiFi?

– Ask yourself these questions first

Silvia Pichler, 
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Choosing the right Navigation technology

The fact that GPS signals don’t work indoors and a different technology approach is needed to enable wayfinding inside buildings is well known. Bluetooth Low Energy-, RFID- and magnetic field-based solutions account for the some of the most prominent indoor positioning and navigation technologies you can find on the market today.

 

Additionally, WiFi has continuously been discussed to serve as a means to enable indoor navigation. Due to the already existing WiFi infrastructure inside buildings, no further extra hardware would be required. This, in turn, may seem like a pretty good deal in terms of cost savings.

 

When looking for a sophisticated indoor mobile wayfinding system, it’s important to measure costs against other criteria.

 

So, if you’re thinking about using your existing WiFi infrastructure to enable indoor positioning use cases and want to avoid any unpleasant surprises, here are some reasons why you might want to reconsider.

 

Questions to ask yourself

 

Accuracy and Latency – What do you expect from your indoor positioning system?

What you should be aware of is that the type of technology you use will determine the quality of results you will achieve. Two of the most important parameters to take into account in your selection process, are accuracy and latency of the positioning.

 

When we talk about accuracy, we refer to the level of congruence of the actual position of a user inside the building and their position shown on the digital map in the app (Blue Dot).

 

Latency means the delay of the updated Blue Dot position on the digital map, as the user moves around. So, the lower the latency, the better and the smoother the overall navigtion experience.

If latency is high, the position will update infrequently, causing the Blue Dot to jump from one position to the next. This makes for rather unpleasant disruptions and a suboptimal navigation assistance.

 

An indoor positioning system based on a BLE Beacon framework is one of the most stable solutions that also brings considerably high accuracy and low latency.

indoor positioning with wifi - map showing high accuracy with ibeacon technology based indoor npositioning and navigation system

This accuracy map ftaken from our project at High Point Market shows that an iBeacon technology based indoor positioning and navigation system delivers very precise localization results.

 

WiFi on the other hand is facing severe problems concerning latency. Since their software update to Android 9, the frequency of scanning for WiFi signals has dropped significantly on Android phones, to an interval of 30 seconds. This leads to a severe lag in updating the real-time position/Blue Dot.

Using only your existing WiFi structure, will also negatively affect the positioning accuracy.

Generally, accuracy for WiFi based systems varies between 5-15 meters. BLE Beacons based systems, for instance, manage an accuracy of down to 2-3 meters.

 

What use cases are you trying to enable?

Depending on whether a WiFi solution suits your needs and fits your expectations, you may choose one or the other technology. The 5-15 meters accuracy you can achieve with a WiFi solution, leaves quite some space for errors.

 

Imagine a trade show involving hundreds of exhibitors. You’ll want the navigation system to be as precise as possible. To find their way through the maze of exhibitors effectively and locate the booth they are looking for, visitors need to be able to rely on an accurate, efficient and stable solution.

indoor positioning with wifi localizing a booth at a trade show

This image shows how a location can be pinpointed on a digital map, using an indoor navigation technology based on BLE Beacons. Especially at big trade shows like Revolver Copenhagen, it is important to know exactly which way to turn to get to a certain booth.

 

A forward-looking approach can be helpful as well. While a rough position may be all you need at the moment, in the future, you may want to use precise indoor navigation or other solutions insideo your building. In that case, you would be better advised to base your indoor positioning system on another technology right away.

 

For navigational purposes, the level of accuracy WiFi has to offer will probably not make sense. Paired with the increased latency, WiFi based indoor wayfinding does not make for a viable product.

 

Who is going to use the technology?

Before launching your mobile wayfinding project, it should be clear what your user group is going to look like. It’s one of the most important criteria to evaluate before putting the indoor positioning system into place. After all, you want to make sure it’s actually going to be used at all.

 

Now, if you’re thinking about using your WiFi strucuture for an indoor positioning system, you want to make sure your users are not mainly iphone users. The reason is that due to constrictions from Apple, indoor positioning does not work with WiFi at all. If you want to allow iphone users to navigate indoors, you have to fall back to other technology, e.g. Beacons.  

 

What is your budget?

As we have already established, using an already existing infrastructure is usually more cost-efficient than any other solution. Other solutions may require hardware, that also has to be installed professionally first. Assuming you have considered the aforementioned points accuracy, latency, user group and use cases in detail, you may very well take the WiFi route.

 

That said, if you do have enough budget to pursue another option that provides you with better results, definitey go for it.

 

Conclusion

So where does that leave us? Before choosing the right technology for your use case, you should make sure to know what you can expect from all options. While WiFi based indoor positioning may score when it comes to cost efficiency, BLE based systems ensure a more accurate and reliable solution. Apple restrictions are making WiFi-based wayfinding impossible and recent Android software updates are introducing new obstacles as well.

 

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