Calibrating is the process of recording the signals of a building, that allow to generate the signal models that Situm uses to compute the location of the users. The calibration process is very simple and can be performed by anybody.
In order to calibrate a building, you will need to fulfill the following requirements:
- To calibrate a building recording Wi-Fi signals you need a device with an operating system version higher than Android 5 and lower than Android 9.
- You need to create your building in Situm Dashboard. Please refer to the step 1 in our Try us tutorial.
- You need an Android device with Situm Mapping Tool installed and mobile data connectivity.
- Your building needs to have Wi-Fi Access Points, in case you want to use Wi-Fi positioning.
- If you want to use Bluetooth positioning as well (or instead of Wi-Fi), you need to deploy Bluetooth beacons in your building. See this tutorial for more information.
How to calibrate
Step by step guide
First of all, open the application drawer by clicking on the hamburger menu in the upper left corner and select Calibration. Once the calibration process is finished, the Positioning mode can be used to test the calibrations.
Once the Calibration mode is selected, the next step is to click over your current location on the map and start walking straight at a steady pace without stopping during each calibration period. The Path width, which represents the approximate width (in meters) of the corridors of the building, can be configured at this point.
From time to time, it is a good idea to click again on the map, indicating your current position. We recommend that you do this whenever walking by something recognizable in the map (e.g. a door). In addition, you should be generating a new calibration point (this is, clicking on the map) at every turn.
Besides, you can:
- Save your calibration. This will stop the data recording process and upload all the data to our cloud.
- Remove the last calibration point. In case you misplaced your position in the map, you can undo it. This will also stop the data recording, and allow you to decide whether to save or erase the calibration.
- Erase the calibration. In case you are not happy with your calibration session, you can just delete it. This will not delete previously saved calibrations from the cloud.
When you click on the "save" button, the calibration session will be stopped, and a summary of the session results will appear. Based on this information, you can decide whether to save or discard this calibration. If you click on Save you will see the following message: “Calibration saved locally” (left image). This means the calibration has been successfully saved to the internal storage and will be updated to the cloud as soon an Internet connection is available. In case you want to upload calibrations manually, you can click on the cloud button.
Once the calibration is saved, you will be able to see the results, just like in the Dashboard. Click on Wi-Fi/Bluetooth/Paths to see the Wi-Fi, BLE, or calibration paths data.
Calibrating with WiFi vs calibrating with Bluetooth
A building can be calibrated by scanning Wi-Fi access points, Bluetooth beacons, or both. By default, both are enabled, but this can be changed in the application settings (left image). In case only one of these data sources is going to be used for positioning, it is highly recommended to disable the other, in order to get better results (right image).
Changing WiFi Access Points
Once the building is calibrated, changing some Wi-Fi access points will not affect the working system. Situm is pretty robust to antenna changes:
- If you add new antennas, Situm will keep on working. Optionally, you may recalibrate to make the most of the new antennas (more accuracy), but this is not necessary.
- If you remove some antennas, Situm will usually keep working (until you remove 50-70% of antennas of that area), no recalibration is required. This is, of course, provided if you have sufficient coverage in the first place.
- If you change the place of some antennas, you may need to recalibrate only the affected areas. Optionally, we may disable those antennas in our backend, so they do not affect Situm (situation number 2) and no recalibration is required.
Tips and tricks
- If you are going to calibrate using Bluetooth and you want to use your own beacons, it is necessary to add their UUIDs to the custom fields of the building. For more information, see How to use the custom fields section.
- If you are going to calibrate a building which has Access Points capable of emitting on different MAC addresses, it is necessary to enable the enterprise mode. For more information, see How to use the custom fields section.
- Calibrations should be done at a steady pace without interruption and should be no larger than, approximately, half a meter.
- To ensure a good result, it is recommended to calibrate in small sections at a time (for example a hallway, then one room, then the other...) and not all in one go.
- This last point makes it easier for calibrations to be modified or erased without the added strain of having to recalibrate a whole floor or set of floors. However, these actions are tricky and should only be performed, very carefully, by a user that understands the configuration section of the dashboard.
- It is also recommended that all places in a building are covered THREE times (or a minimum of two) to have a good calibration.