title: Bluetooth RSSI value fluctuation
body: <p>I'm trying to use RSSI values to create a positioning system in my home. </p>
  
  <p>I'm using the neXenio library as a base, the only changes I have made from this have been implementing logging to a database:
  <a href="https://github.com/neXenio/BLE-Indoor-Positioning" rel="nofollow noreferrer">https://github.com/neXenio/BLE-Indoor-Positioning</a></p>
  
  <p>I'm using 4 Minew I7's for the beacons and they are currently set to broadcast just iBeacon type adverts at 300ms. They are positioned in a square shaped room and a cross type layout and each beacon is around 2.2m apart. There are no obvious obstructions other than normal living room furntiure. For each test run I do I place my phone in the centre of the room and gather data for around 10-15 minutes at a time. Data gets sent to a database for me to look at after.</p>
  
  <p>The issue I'm having is the singal strength fluctuates massively all the time, to the point the data is basically unusable. 
  <a href="https://imgur.com/a/4c3D4l7" rel="nofollow noreferrer">Graphs from a typical test run</a>.</p>
  
  <p>Should there be that much difference when the phone is completely still ? I'd expect there to be some slight differences from just the nature of signal propagation but not this much.</p>
  
  <p>Is this to be expected or can these be improved upon somehow ? If this is expected then I will have to look at combining some other sensor data to help improve accuracy.</p>
  
  <p>Thanks</p>
  
  <p>Edit:</p>
  
  <p>After running some more tests, I compared values over time (I had previously only compared rssi,distance and mac address). This has led to find a consitant osscilation pattern <a href="https://imgur.com/a/cwt2CrD" rel="nofollow noreferrer">Newest test run</a>.</p>
  
  <p>This has also led me to this overstack question:
  <a href="https://stackoverflow.com/questions/49634513/is-there-an-explanation-for-the-regular-oscillation-experienced-in-bluetooth-rss">Is there an explanation for the regular oscillation experienced in Bluetooth RSSI</a></p>
  
  <p>If I am only advertising iBeacon type adverts then this wouldn't apply? But it seems strange how it matches me issue.</p>