is there a way to show the beacon direction as an arrow point the direction to the beacon? I know it is possible to change the color according to the proximity of the beacon but what I need is a direction to find the beacon.
You can't do this just with one beacon as all you have is the received signal strength (RSSI). The Determining Location Using Bluetooth Beacons article explains more and references a paper that shows a workaround that might help when using just one beacon.
Sorry, you cannot get direction to a Bluetooth beacon. A Bluetooth receiver on a mobile phone is omni-directional. It works much like an old-fashioned AM radio. You can get some idea how far away a radio station is by how much static you hear, but there is no way to know which way the transmitter is by standing still and listening.
The paper that #Simon-Judge mentions in his answer basically suggests it could be possible to figure out roughly which way the transmitter is by spinning around in place and measuring signal. To take the AM radio analogy, this is similar to pointing the antenna in each direction in 180 degrees to see where it picks up the signal best. While this might work with some degree of success, it certainly isn't going to plot an arrow on the screen for the direction of the beacon.
Related
Is it possible to find an accurate position of a person in a room using multiple Bluetooth beacons set up around the room through proximity detection? I've done some research and it says it is difficult to detect proximity with a Bluetooth sensor but can I overcome this through using multiple Bluetooth beacons? The point is you can use multiple Bluetooth beacons to triangulate positions and we'll be developing an iOS app that dictates the user (blind or disabled) where obstacles are. I'm wondering if this idea is doable and am curious how I can achieve accurate proximity sensing with Bluetooth beacons.
Thank you.
For anyone who thinks of this idea in the future:
Bluetooth really isn't ideal but there can be other ways such as using
other types of sensors.
I want to locate an object position inside a house( one floor).
The object will have a iBeacon on it.
What are the best approach.
With api, i can get distance from the iBeacon, but this doesn't reflect position.
One idea was to have 4 fixed iBeacon on the floor, but seem's i can't get the distance from the moving iBeacon to a fixed.
Any idea?
iBeacon isn't the right technology for this - at least not with a single receiver.
iBeacon only gives you an approximate distance. If you have multiple beacons in known locations then you can try and triangulate the receiver's position but you can't use this information to determine the location of another transmitter in an unknown location - only estimate its distance from the receiver.
Even using known, fixed transmitters it is difficult to locate the receiver with any accuracy due to the nature of the Bluetooth signals.
If you had multiple iBeacon receivers on the floor at known locations then it might be possible to determine the location of the transmitter.
I am developing an iOS application in which I need to know the exact distance and direction of the device from the beacon. I am using Estimote beacon.
I have used iOS's CLLocation as well as Estimote's framework but both of them give an incorrect value for the distance. Moreover, the values fluctuate a lot, the beacon even goes into unknown state (accuracy -1.000) a lot of times.
I have also tried to use the formula given here:
Understanding ibeacon distancing
but in iOS, it seems there is no way to get the txPower or measured power of Beacon.
I have searched a lot but nowhere I found a satisfactory way to find the distance accurately.
is there any other way which can help me in finding accurately the distance and direction of iOS device from Beacon?
The distance is computed by comparing the received signal strength (RSSI) with the advertised transmitted power (txPower) of the beacon, as the signal strength in theory is inversely proportional to the square of the distance.
But there are lots of other things that can affect RSSI, including obstacles, orientation of the antennas, and possibly multi-path (reflections). So it's difficult to accurately measure distance based on this information.
Another way of measuring distance is using round-trip-time (RTT): you send something to the beacon, and you measure how long it takes to come back. But this requires a fixed response time, and on this sort of scale (meters), there are probably enough variable delays here and there that it might severely affect the calculation.
Direction would require either triangulation or multiple directional antennas, I don't believe that's the case in this scenario.
In short, you can get a rough idea of the distance (which is why it's good for proximity alerts), but accurate distance or direction would require different technologies.
Why do you need them? There may be alternatives based on your specific scenario.
EDIT
If you have a large number of beacons around, and you know their exact positions, it might be possible to pull off the following:
use at least 3 beacon distances to compute your exact position by triangulation
from there, as you know the position of the beacons, you can compute the distance and direction of any of the beacons (or anything else, really)
Of course, depending on the actual accuracy of the beacon distance measurement provided by the SDK, the result might be more or less accurate. The more beacons you have, the more precise you should be able to get (by picking only those that return a distance, or by eliminating those that are not "compatible" with the others when computing solutions).
Even having 3 or more beacons with fixed positions, you still won't be able to receive very accurate positioning without some serious and complex noise reduction. That's because radio waves are prone to being affected by diffraction, multipath propagation, interference and absorption - mostly by metal objects and water particles (therefore human bodies are strong signal blockers). Even phone's alignment (antenna position) can have a significant impact on the proximity readings. Therefore, without implementing alorithms for noise reduction, trilateration can give you accuracy of about 5 meters.
You can find some examples in Obj-C (https://github.com/MatVre/MiBeaconTrilaterationDemo) and Swift (https://github.com/a34729t/TriangulatorSwift) and check how they work for you.
Cheers.
I am using an iBeacon, and using triangulation and trilateration (or something similar), want to be able to locate an exact (or fairly accurate) distance between the iBeacon and user's device (in feet/metres/e.t.c). What is the best way to do this, and how would I do this?
I forgot to mention: I understand that it is possible to find proximity (i.e near, immediate, far, etc.), however as mentioned, ideally I am looking to find an accurate distance (maybe by combining RSSI, accuracy, and proximity values).
For this you should use RSSI (Received Signal Strength Indication) of an iBeacon. The signal strength determines how close or far it is from you. But the problem is that:
Every beacon's RSSI might differ distance, accuracy.
If beacon is behind the wall or any static obstacle the RSSI-Distance-Ratio will not work.
Therefore instead of Triangulation or Trilateration you should go for Fingerprinting. This will work better then rest of the techniques.
Place obstacles all around you.
Make reference points on your map.
Calibrate your app with that location i.e. Get the signal strengths from atleast 3 nearest iBeacons and save it against that reference points.
Do this for all other reference points.
(If you can) Do this twice or thrice and take average and store in database.
Now you have laid map of calibrated reference points. (This will handle all different RSSI-DIstance-Ratios of all the beacons)
Now whenever you are at any position compare it with the nearest point and you will get to know the closest location of your reference point.
If you are using google maps, the lat long they provide is upto six decimal place i.e. 0.11 meters which i think is preety much accurate in a room as well.
I guess this helps :)
Please mark this the right answer if it works.
In iOS the Core Location beacon information you get when you range a beacon includes both a "proximity" value (far/near/immediate) and an "accuracy" reading, which is actually approximate distance, in meters.
In order for the distance reading to be as accurate as possible, you should really calibrate your beacons. To do that, you put the beacon exactly 1 meter from the receiver and take a reading. The receiver gives you a "measured power" reading, which you then set on the transmitter. The measured power reading is used in calculating the distance reading.
Distance readings are very approximate, and are subject to interference from the surroundings.
The Apple sample app "AirLocate" shows working code for calibrating a beacon, and I believe it also displays
I'm wanting to know if what I want to do is even possible and if there is a good practise that I should follow.
For my experiment I have a collection bluetooth low energy beacons laid on the ground with each projecting out their own BLE signal. Each of these signals is getting read in by a fourth device that takes the corresponding RSSI value and uses it to determine it's position within the area.
Following this I now want each of my beacons that are laid on the ground to know the distances that separate them from each other. So my questions are as follows:
Is it possible to have the beacons on the ground broadcast different signals using two different UUID values?
Can a beacons both read and broadcast a signal at the same time? By that I mean the beacons will still be sending out their initial signal being read in by my fourth device whilst also reading in the distance value from their fellow broadcasting beacons on the ground.
I'm not sure if I've done a good job at describing what it is I'm wanting so I've (terribly) drew a picture in order to show what I want do and describe what I've got so far.
Key:
Black dots are my beacons on the floor
Green dot is my reader that finds its distance from the floor beacons. On the green dot is another app that is projecting out a BLE signal which the floor beacons are reading.
Purple line is the BLE signal being sent out from my reader device.
Yellow line is the RSSI value showing the beacons distance from the BLE signal being projected
Blue line (this is the key to this post) is meant to represent the beacons projecting and reading their own BLE signal so they can find their distance from each other.
Green line is then each beacon sending its distance from the other beacons to the reader.
At this point Bluetooth Smart-only devices currently do not support simultaneous peripheral/central mode.
What I would suggest is using the nRF51922 which supports concurrent BLE/ANT.
ANT is fully capable of doing this functionality for you as it supports all kinds of topologies, and you can relay your final information over BLE, or go with an nRF51422 and stay ANT only, I believe all latest Sony and Samsung devices support ANT anyway so it might be enough for you.
You can read more about it at http://www.thisisant.com