Overview

This article will cover techniques for improving floor-to-floor and indoor-to-outdoor map transition for wayfinding using Meridian maps.

Meridian maps are intended to be used for indoor wayfinding, however there may be occasions where outdoor wayfinding is so integral to the user experience that it must be included. Such an example is a college campus where students need to have the indoor wayfinding in the multi-level student union building but will also need wayfinding to a classroom in another part of the campus. Supporting this use case will require floor-to-floor and indoor-to-outdoor transitions and eventually outdoor-to-indoor transitions with location awareness. Meridian maps supports both indoor and outdoor transitions. For this to work, all wayfinding must be done using Meridian maps. Meridian does not have any integration with third party maps such as Google or Apple maps.

GPS and BLE

Global Positioning Satellite (GPS) signal degrades drastically when a user is indoor, therefore, it cannot be used reliably for indoor wayfinding. However, Bluetooth low-energy (BLE) beacons can be used for both indoor and outdoor wayfinding. To differentiate when the system is using BLE for wayfinding, a blue dot is shown on the Meridian map. When it is using GPS, a green dot is shown. As a rule of thumb, blue dot indicates BLE and green dot indicates GPS.

NOTE: When beacons are deployed at the recommended density of 900 sq. ft., the blue dot appears when the mobile device hears a beacon; it will provide 3-5 meters of accuracy. Third-party GPS based outdoor mapping apps typically support up to 10 meters of accuracy, but Meridian is architected to only show a green dot when the mobile device receives at least 5 meters of accuracy confidence. That means if the mobile device is in an area where the GPS confidence is weaker than 5 meters, no green dot will be shown on the Meridian map. This may cause a delay in the appearance of a green dot on the Meridian map when using GPS.

Meridian Map Settings

By default, the Meridian map is uploaded and configured as an indoor map.  For indoor maps, Meridian's location engine defaults to using BLE for blue dot wayfinding.  Meridian maps can also be configured to use GPS for outdoor maps as well.  When a map is configured to use GPS, it will no longer use BLE.

With the two different options available, choosing one option over the other really depends on the use case. Meridian is very good at showing the blue dot on the Meridian map when the device hears a beacon; however, when it comes to GPS, showing the green dot has its challenges. Consider the following:

• If the user is outside a building and the mobile device hears a beacon signal it will show the blue dot and place the user on the map of the beacon it heard.
• If the user was inside the building and has walked outdoors, the blue dot will continue to show on the indoor map until it stops hearing the beacon, at which point it turns to a gray dot, then change to a green dot when it receives a good GPS signal. For the green dot to appear on the map, the mobile device must hear a GPS signal that has a confidence of 5 meters or better. The process of establishing a good GPS signal and loading the map may cause an unacceptable delay in the transition from blue dot to green dot transition.

Configuring an Outdoor Map to Use GPS

The most common technique for using navigation outdoors is to set an outdoor map to use GPS.  An outdoor map is uploaded as a floor map into the Meridian account the same way indoor floors are uploaded for a building. Since it will upload as an indoor map by default, it will need to be changed to use GPS. 

To change the map settings to use GPS, navigate to the floors list and click on the target outdoor map:

1. In the floor settings page, click USE GPS.
2. Click Save.

NOTE: Beacons placed on a map with this setting will be ignored. DO NOT place beacons on a map with USE GPS checked.

A Meridian map configured to use GPS will only show a green dot if the GPS signal received on the mobile device is better than 5 meters of accuracy.  Below that threshold, no green dot will be displayed.  If the signal was better than the threshold for a short period of time, then degraded, the green dot will turn gray and eventually disappear if the signal gets too weak.  If signal quality is poor, the green dot may never appear.

 

Configuring an Indoor Map to Use GPS

As mentioned earlier, an indoor Meridian map defaults to using BLE for blue dot wayfinding.  But, an indoor map can be configured to support both BLE and GPS on the same map.  This is typically used when the indoor map includes a large open courtyard, too large to use beacons, that is open to the sky above.   

To create an outdoor area on an indoor map, do the following:

1. Navigate to Floors > Select the floor > click on the Placemark icon.

2. Click on Add Placemark

3. Click on the Polygon Placemark option

4. Draw the area that is open to the sky above.

5. Scroll down the Placemark page to Generic placemarks and select Outdoor Area.  Selecting the type as Outdoor Area for this placemark polygon will use GPS for location awareness instead of BLE when the user is inside this area.

6. After you click Save, the polygon will be displayed on the Meridian Map.  The shape of the polygon can be adjusted by moving the handles.

 

Understanding Map Transitions

Since the Meridian-powered mobile app relies on BLE or GPS signals to locate the user on the Meridian map, it is critical to place beacons for best RF signal propagation and draw an outdoor area polygons where GPS signal is strongest.

When a user transitions from one map to the next, whether it is floor-to-floor or indoor-to-outdoor, the mobile app has to do the following:

1. Listen for the BLE or GPS signal 
2. Display the corresponding map
3. Locate the user

Each of these activities takes time and may affect the app's performance in a way that delivers an unsatisfactory user experience.  In order to improve the user experience we want to reduce the amount of time it takes to go through this process.  

Listening for the BLE or GPS Signal

Each mobile device will hear the BLE signal or GPS signal differently so there is no way to tune the deployment for all mobile devices.  From experience, iOS mobile devices have the most consistent reception of RF and GPS signal across multiple devices.  The signal reception for Android mobile devices may vary quite a bit and are more inconsistent with older models.  The only factor that can be improved here is the placement of the beacons for BLE signal. 

For the purpose of this article, we will only cover beacon placement for the purpose of optimizing map transitions.  For more information about beacon placement go to Deploying Aruba Access Points and Beacons for Meridian Wayfinding.

 

Displaying the Corresponding Map

When a map is on the screen, it is cached for a short period of time.  But, if it is determined that a new map is to be displayed it must have an Internet connection to fetch the map that corresponds the the signal heard, and then it will load the properties of the map.  Here, we can improve by minimizing map properties such as map size, placemarks and routes.

Locating the User

After the map is loaded, the mobile app will zoom into the user's location and draw the dot to represent the user's location on the map.  Timing of this is all based on the processing power of the mobile device.

 

Optimizing Map Transitions

Floor-to-Floor Transitions

Floor-to-floor transitions are not much of an issue in most cases.  However, we have come across scenarios where a user climbs up a stairwell, enters a new floor and walks halfway down a hallway before a blue dot shows up on the map.  If the user has a route created, the map of the previous floor may be visible a few seconds longer that they would like. 

To remedy this, beacons can be placed in the stairwell directly above the door entering the floor, ensuring it does not have a line of sight to nearby beacons.  This causes the new floor map to load as the user enters through the stairwell door.

Indoor-to-Outdoor Transition

The techniques applied to optimizing for Indoor-to-Outdoor will also work for Outdoor-to-Indoor.  The following steps will help to optimizing the transition:

Step 1. Configure map as indoor map.

Step 2. Use outdoor area polygon where GPS is required

Step 3. Place beacons near the outside of the entrance to the building

As soon as the user steps outside the building, mobile app will immediately get the outdoor map and draw a blue dot to represent the user's location.  This helps to mitigate situations where the GPS signal may not be strong enough to determine the user's location.  When the user walks away, the BLE signal will get weaker.  As the GPS signal gets stronger, since the outdoor map is already loaded, the app just has to transition from a blue dot to a green dot.  

For outdoor-to-indoor, this is also applicable.  As the user approaches the entrance to the building, the green dot will transition to blue on the same map.  Since the location engine is now in BLE listening mode, as the user walks into the building and the mobile device hears the indoor beacons, it will load the map and show the user's location.  

Summary

This technique will improve floor-to-floor and indoor-to-outdoor transitions providing your user a more satisfactory wayfinding experience.  There may be some delays, but there should not be any noticeable delays that makes the app useless.  If you should have additional questions, please feel free to contact https://asp.arubanetworks.com/.