I am using the RadiusNetworks library for measuring the distance to iBeacons. The official app from RadiusNetworks (iBeacon Locate) provides a calibration feature to improve accuracy.
How do I perform a calibration when using the library as part of my application?
Thanks & Best
ben
The calibration function in the BeaconScope app will give you a number to be configured into a hardware beacon to make distance estimates as accurate as possible. Once set, the beacon transmitter will emit this value to receiving devices (both Android or iOS). Because it is transmitted over the air, there is no need to manually configure the Android iBeacon Library with the value. The library will read it out of the beacon transmission.
For this to work, you need to configure the calibration power value into your beacon. How you do this depends on the type of beacon you are using. Most beacon vendors allow this, but each product has a different procedure. For my company's RadBeacon products, for example, we have iOS and Mac apps to set this value over the air.
It is hard to estimate the accurate distance using RSSI of the iBeacon.
You have to use log distance path loss model(shortly, LDPL) to change RSSI to distance.
In LDPL, you need below two parameters, simply.
Initial RSSI
Path loss exponent
And I recommend you BeaconBox for Android.
You can get these two parameters using this app.
Also, you can get Java source code for changing RSSI to distance.
I hope that you achieve the goal!
Related
I am developing an android application to find the distance from Eddystone beacon to the mobile device. I am using Android Beacon Library and following this example. when I locate my beacon nearly 1 meter away from my device, it shows like below. it shows small values and changes continuously. How to solve this and get at least nearly accurate value.
The "underestimate" shown in the question suggests one or more of the following may be true:
The Beacon has not been calibrated.
The receiving phone device model may have an unusually high measurement of signal strength requiring a device-specific adjustment of its distance calculation.
See here for more information on how to address these issues.
Even once you address the above, set your expectations properly. Bluetooth LE distance estimates are rough. They are useful for telling you if another device is within a couple of meters or many meters away. But they cannot tell you the precise distance to a bluetooth transmitter.
guys
I'm using Altbeacon Android Library to do some Bluetooth app for demo. It provides with a getDistance() method that I can use to get distance between my phone and external Bluetooth device with Altbeacon protocol uploaded. However, as the devices are different, I think the distance might vary with a large error (I get 0.05m when I'm at 1m away, so on and so forth). This makes me think that if we do some calibration work for the getDistance() method will be useful. Is there any way of doing this? (Currently I have no idea how to modify the getDistance method, maybe #override it? Not very sure)
Many thanks.
I am not aware of any calibration functionality in the library. However, you can change distance calculation by implementing your own DistanceCalculator.
The default distance calculator is ModelSpecificDistanceCalculator and it set in the BeaconServices onCreate method (check this). So, simply creating your own version of the DistanceCalculator and set it after BeaconService is created can do what you want;
// after beacon service is created
DistanceCalculator customCalculator = ...;
Beacon.setDistanceCalculator(customCalculator);
However, you should now that device is also causes variation;
Each model may have a different Bluetooth chipset and antenna, and therefore may receive a different signal level when in the same position relative to a beacon. In order to address this, the library uses a different formula for calculating distance for different Android device models. Because not all devices have custom formulas built into the library, the library will fall back to the default device calculation for the Nexus 5 if no matching formula is found.
For more information about distance calculation, please visit AltBeacon - Distance Calculations page. This page also explains how distance calculation works as well as how you can contribute to enhance the library for device variation.
By the way, you can also check CurveFittedDistanceCalculator but this one requires you to give device specific coefficients (explained in this page). For more info about this, check its source code.
I am working on iBeacon Application, which will detect my nearest iBeacon and connect to it & serve further process.
I am done with finding my nearest iBeacon and get its all properties like: UUID, Accuracy, Major, Minor, RSSI, Transmiter Power etc.
Now i want to search that, iBeacon is in which direction from my device wheather it is left/right/top/bottom or any other direction corners?
Below my nearest iBeacon search list.
Unfortunately, this is not possible:
Don't expect to be able to determine the direction to a beacon. Because beacons are typically omnidirectional transmitters, although you can estimate distance, you cannot estimate direction.
See: Fundamentals of Beacon Ranging
The thing you're trying to do is not possible using only one iBeacon. You are looking for something like trilateration which requires a minimum of 3 beacons. This might get you started Triangulate example for iBeacons
This technology works due to the fact that we know the coordinates originally iBeacon. To get the coordinates iBeacon you need to know at least their local coordinates. The application uses a local coordinate system on which iBeacons serve as reference points. If you do not know your coordinates and iBeacon then you will have nothing to calculate
I have been working with Estimote Beacons for Android App Development. I'm getting beacons range and distance from Android. But, i want to show the directions and location of specific beacon to the user to reach specific beacons. So, is it possible to show the direction and location of beacon in Android app to reach to specific beacon?
Getting directional information to a beacon is much, much more difficult than simply getting a distance estimate.
A beacon by itself does not provide any directional information. It is simply a radio transmitter with which you can use the strength of the signal to get a rough estimate of the distance.
It is possible to do full indoor location of a mobile device using multiple beacon transmitters at known locations. Only if you know the specific location of the mobile device vs. the location of beacons can you do what you suggest. Doing this, however, requires sophisticated custom software, non-trivial site surveys, and beacon locations that do not change.
Several companies offer systems that do this, but none are free or open source, and it most certainly is not a core beacon feature.
I'd like to know if iBeacons require a calibration phase (i.e, like Wi-Fi fingerprinting).
When trying to measure location based on Wi-Fi signal strength there's a need to do an arbitrary prior scan at the location you want to map.
I'd like to know if Iphone/Android already gets a fair coordinate based on ibeacons signal without a map phase.
If you want accurate distance estimates, then yes, it requires calibration.
However, it is not as temperamental as the wifi calibration. And often you can use the default calibration that comes with the particular iBeacon hardware.
For example my company, Radius Networks, makes a number of iBeacon hardware solutions and those are calibrated here in our lab. While environmental changes will effect that setting it often doesn't change things too drastically. For the most part the factory setting will be just fine for many use cases.
Obviously this is not the case if there is some drastic interference, such as installing the iBeacon behind a metal wall, or in a room that will be very crowded (people are notorious for absorbing RF). In those cases it would be best to recalibrate the beacon.
One difference to note about beacon calibration vs. something like wifi calibration, is that the beacon is configured to broadcast a calibration value. That value represents the expected RSSI that a phone will see at 1 meter away. That is then used to interpolate the distance estimate.