Creating a High Performance IPS with Dead Reckoning and Sensor Fusion

September 22, 2020 by Aaron Wong
Read in 4 Minutes

When it comes to indoor positioning, there are a few different ways to provide accurate positioning and the blue dot experience. While on the surface, many of them rely heavily on Wi-Fi or Bluetooth Low Energy (BLE), underneath it all, most of them harness the science of dead reckoning and use sensor fusion to bring indoor location use cases to life.

What is dead reckoning in navigation?

Dead reckoning is a method of positioning that relies on inertial measurements. An inertial navigation system measures motion and/or rotation using a mobile device’s accelerometer and gyroscopes, respectively. Dead reckoning is the process of calculating a device’s position by using a determined starting point and advancing that position based on estimated speed, distance, and direction. 

Dead reckoning is very cost efficient as it requires no additional hardware or fingerprinting, but it typically presents an issue as inertial measurements can only determine where a user is relative to where they began. Another issue is the concept of ‘drifting.’ Over time, the further a device traverses, the further the marker, in most cases this will be a blue dot, will drift from the real position. This is where sensor fusion comes in.

What is sensor fusion? 

Sensor fusion is essentially the ability to bring together inputs from multiple data sources, such as sensors and signals, to form a single model of a position. The resulting model is more accurate because it calibrates for the different sensors and signals, painting a more complete picture. 

Sensor fusion enables us to combine device data coming from the gyroscopes and accelerometers, with sensor data, to fill in each other’s blanks. To date, this method is most commonly discussed in its usage with automated vehicles. In the context of an indoor navigation system, the location is indicated by a device’s dead reckoning system, and then evaluated and adjusted by the sensors within a facility. This way, when the drifting naturally occurs, the sensor data will nudge the blue dot into a more accurate position thanks to sensor fusion.

Building a high performance positioning system

Positioning systems are a lot like cars - they’re all composed of the same parts. Every car has wheels and an engine, and every Indoor Positioning System (IPS) has the same bones. But as with cars, there can be vast differences in performance depending on how it has been built. It doesn’t necessarily matter where the signal comes from, the key differentiator is the engineering under the hood.

One of the exciting things about building an IPS that leverages dead reckoning and sensor fusion, is that it provides the opportunity to engineer something exceptional. By using sensor fusion, dead reckoning can be combined with ultra-wideband, BLE or Wi-Fi to engineer an exceptional indoor blue dot experience that leaves the drifting to the sports cars.

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Aaron is a Solutions Architect and an innovative software developer with professional experience in the full development cycle of next-generation applications and customizable solutions. When he's not helping get maps in your apps, he can be found rock climbing and spending time in the mountains.