Augmented Reality mixes the digital and physical world, allowing us to create interactive experiences that enhance real-world scenes with computer-generated information. In a museum’s app, AR allows us to overlay author information on top of the art pieces. In a shopping mall, an AR-based app might show us the current promotions of a store just by pointing our camera toward it. And of course, a wayfinding app that leverages the power of AR might show us the way by overlaying the calculated route on top of our camera’s view!
Positioning is an important piece of any wayfinding AR system: in the end, you need to know where you are in order to overlay the virtual objects where they should be. AR-based apps have at their disposal a wide range of positioning technologies, each best suited for a specific use case. But… which positioning technology is best suited to build AR apps?
In this post, we’ll show you in which cases Situm is the best option for your AR wayfinding app by comparing it with the main alternatives.
GPS + Compass
The first choice is to use the GPS and the compass of the smartphone. The GPS provides us with our geolocation anywhere in the world, and the compass provides us with the 3D orientation of the smartphone: therefore, we can represent objects with respect to that location and orientation.
This is one of the approaches Google Maps uses to show us the route on top of our phone’s screen view. This is achieved by using GPS information and visual navigation, which we’ll explain later. Another great example is Pokemon GO, which uses the GPS data of the player to feed the game dynamics and to represent the Pokémon for the player(s) that want to catch them. Finally, we’d like to mention our partner Telecom Square, who has developed PinnAR, an app with over 0.5 million users (and counting) that, using Augmented Reality, allows you to find and navigate to your favourite places in a city.
Where’s the catch? Well, if you have been reading us, you know already! GPS signal doesn’t penetrate roofs or walls, so if you want your app to work indoors (or in dense urban environments), you need an indoor positioning technology.
Visual navigation
Visual navigation is a nice alternative to GPS, compass, and to some indoor positioning alternatives as well. Visual navigation is a kind of camera-based positioning system, that derives the smartphone location (and orientation) by matching the smartphone captured images/video against a previously recorded database.
In 2019, Google famously mixed visual navigation and Street View (the previously recorded database) to power up Google Maps’ outdoor navigation capabilities. More recently, they started following a similar approach to provide that same capability, but in indoor spaces. Of course, this requires building the visual database of each building, which might explain why this technology works in just a few selected places so far.
Visual navigation is usually accurate both in terms of position & 3D orientation accuracy, but it has two important drawbacks:
- Image occlusion/scene ambiguity. Image recognition might not work if the scene is occluded (e.g., a crowd blocks the view of the relevant landmarks of the space) or if the scene captured is ambiguous (think of an office corridor: how many similar corridors are there in a typical building?).
- Image database construction. Capturing all the visual landmarks of a building and storing them in a database is not an easy task, usually requiring specialized equipment such as 3D cameras & lasers.
Still, if you think visual navigation is for you, you might want to start by looking at ARCore (Android) & ARKit (iOS). These libraries also provide nice utilities to build AR-based apps such as motion tracking, environmental understanding and light estimation.
Light-based
Another interesting technology for AR navigation apps is light-based technology. Light-based indoor positioning works by installing special lights, each emitting a unique “light-code” that can be detected from the smartphone camera.
In AR apps, the user is always pointing the smartphone camera forward, so both the back & front lens can capture these codes and pinpoint the user’s location accurately. The main disadvantage is, of course, the need to install special lighting systems.
Bluetooth beacons
Bluetooth low energy (BLE) beacons appeared in the 2010s, and from that date, two players dominated the market: Apple iBeacons and Google Eddystone. These IoT devices work like a lighthouse by emitting a Bluetooth package now and then. The smartphone receives it, measures signal parameters such as the Received Signal Strength (RSSI), and based on all the captured information it attempts at estimating the indoor geolocation (using different techniques such as trilateration or fingerprinting).
BLE beacons are inexpensive, small and unobtrusive. They can be easily installed almost anywhere, require no data or electrical connection as they are battery operated, and are very flexible in terms of configuration parameters. Beacons can be used on both Android & iOS devices with great support.
Their main drawback, however, is that they don’t usually provide great accuracy by themselves. And great accuracy is paramount in AR navigation apps. Nevertheless, their performance can be greatly improved by using them in conjunction with other positioning technologies/sensors (such as WiFi signals, inertial sensors, etc.). You’ve guessed it! This is what Situm does.
Situm’s technology to power up any indoor & outdoor augmented reality navigation app
Situm’s algorithm mixes different signals to best position the user, taking advantage of the strong points of each of them while compensating for the not-so-strong ones. The core technology behind Situm IPS merges preexisting information in the environment (magnetic fields, Bluetooth, Wi-Fi) with data from inertial sensors inside smartphones (compass, gyroscope, and accelerometer), thus offering precision and stability without needing to invest in a ton of dedicated infrastructure. Most of these signals are already in the building or smartphone!
Indoors, in addition to the lack of GPS signal, there is a high amount of electromagnetic interference due to environmental elements (wiring, escalators, machinery, etc.). Systems that rely on the compass or magnetometer to estimate the device’s orientation in space are usually vulnerable to these interferences and, therefore, susceptible to estimating wrong orientations that cause spins or other alterations. To solve this, Situm fuses all the inertial sensors together, computing the orientation of the smartphone in 3 dimensions (yaw, pitch, roll) and *to achieve* a 3D orientation very stable, accurate and smooth. This is paramount to building AR-based apps: otherwise, AR visual elements will not be placed in the right location or worse, they will be shaky.
Additionally, Situm can also be used in combination with the technologies described above:
- Situm already uses GPS, so indoor positioning can be combined with outdoor positioning as well.
- Situm fuses knowledge of the environment (Bluetooth, WiFi) to be able to estimate robustly and stably the position and orientation of the device in space.
- The developer can use Situm information and at the same time rely on visual navigation systems such as AR Core and AR Kit.
- Other features provided by Situm are a great complement to augmented reality technology. Indoor guidance “comes to life” with comprehensive maps that guide the user with step-by-step instructions, highlighting places of interest and relevant information to create an amazing experience that merges the physical and digital worlds to take advantage of the best qualities of both.
In Japan, for example, as previously mentioned, Situm is already working with Telecom Square and its PinnAR app, a benchmark in indoor augmented reality navigation that guides the user through the interior of buildings as well as through streets using their smartphone camera and overlaying the guiding directions on top of the actual image.
Indoor positioning technology is undoubtedly a crucial part of creating the best interactive experiences, a resource that is already part of our present and future. The divisions between the physical and digital worlds are getting more and more blurred, and by taking advantage of the best of each we can create innovative products whose functions are increasingly in demand.
If you are interested in an indoor navigation solution using augmented reality, do not hesitate to contact us and tell us about your case, we will be happy to help you!