• Home
  • Archive
  • Tools
  • Contact Us

The Customize Windows

Technology Journal

  • Cloud Computing
  • Computer
  • Digital Photography
  • Windows 7
  • Archive
  • Cloud Computing
  • Virtualization
  • Computer and Internet
  • Digital Photography
  • Android
  • Sysadmin
  • Electronics
  • Big Data
  • Virtualization
  • Downloads
  • Web Development
  • Apple
  • Android
Advertisement
You are here: Home » Note on Calculating Distance From RSSI Value of BLE Devices

By Abhishek Ghosh March 18, 2020 7:26 am Updated on March 18, 2020

Note on Calculating Distance From RSSI Value of BLE Devices

Advertisement

A quick question from one reader after publication of Smartwatch BLE to Trigger IBM Watson IoT Event was “can I measure the distance in meters and broadcast?”. The answer is – it is not reliable with easy formula against a single BLE device. If we were using Raspberry Pi, then we could think of using complex coding.

BLE technology and works with Indoor Location Positioning is not new. RSSI stands for Received Signal Strength Indicator. The strength depends on distance and Broadcasting Power value. dBm and RSSI are different units of measurement. They represent the same thing: signal strength. RSSI is a relative index while dBm is an absolute number expressing power levels in milliwatts. RSSI tends to fluctuate due to the factors influencing radio waves—such as the device itself, the chipset, absorption, interference, diffraction.

Common propagation path-loss models include the free space propagation model, the logarithmic distance path-loss model, etc. Studies have shown that the channel fading characteristic follows a lognormal distribution. RSSI distance measurement generally uses the logarithmic distance path-loss model. It is expressed as:

Advertisement

---

 

RSSI = −10n lg(d/d0) + A + Xσ

where d is the distance between the transmitter and the receiver, and n is a path-loss parameter related
to the specific wireless transmission environment. A is the RSSI with distance d0 from the transmitter. Xσ is a Gaussian-distribution random variable with mean 0 and variance σ. For the convenience of calculation, d0 usually takes a value of 1 meter. Since Xσ has a mean of 0, the distance-loss model can be obtained with

RSSI = −10n log(d) + A

where A is the average measured RSSI when the received node is 1 meter away from the transmit
node which is related to the RF circuits of Bluetooth nodes. By gathering the RSSI values for Bluetooth
beacons at different distances and using the least-squares algorithm to fit the parameters, we can obtain
the RSSI distance model.

Measured Power is a factory-calibrated constant of expected RSSI at a distance of 1 meter. BLE devices broadcast in pulse. Advertising Interval is the time between each pulse with a value range between 100 ms and 2000 ms. The shorter the interval, the more stable the signal.

There are different techniques to enhance the precision of a BLE indoor positioning system: channel diversity, Kalman Filtering, weighted trilateration method and so on.

If we blindly use some easy formula to measure distance, such as :

Distance = 10 ^ ((Measured Power – RSSI)/(10 * N))

Where N is constant which depends on the environmental factor with a range 2-4. Then we need to know the “Measured Power” of a bare ESP32. The discussion on ESP32 forum :

Vim
1
https://www.esp32.com/viewtopic.php?t=818

…does not show much promise. Reading the analysis :

Note on Calculating Distance From RSSI Value of BLE Devices

Vim
1
https://github.com/neXenio/BLE-Indoor-Positioning/wiki/RSSI-Measurements

…proves that effort to calculate exact distance from RSSI value of ESP32 is not a DIY job. I would rather suggest thinking to involve two LEDs for Samsung Smartwatch as Proximity Switch project or use a buzzer. First, make the buzzer or two LEDs to give a signal of entry and exit.

With a buzzer, the effect will become like a chat room sounds.

Thereafter modify the code of Smartwatch BLE to and Trigger IBM Watson IoT Event.

Tagged With rssi to distance , environmental factor rssi , measure distance with ble , measure distance ble , how to calculate the distance between BLE devices , esp32 measure distance with bluetooth , esp32 calculate distance , distance from rssi android , dBm ble in meter , ble rssi distance

This Article Has Been Shared 338 Times!

Facebook Twitter Pinterest
Abhishek Ghosh

About Abhishek Ghosh

Abhishek Ghosh is a Businessman, Surgeon, Author and Blogger. You can keep touch with him on Twitter - @AbhishekCTRL.

Here’s what we’ve got for you which might like :

Articles Related to Note on Calculating Distance From RSSI Value of BLE Devices

  • ESP32 Arduino OLED Display Example (I2C)

    Interfacing OLED without I2C is difficult with ESP32, as it requires 6 connections. I2C based OLED display need only two IO lines.

  • ESP32 Arduino : Fetching Current Weather Data (No JSON Parsing)

    In this guide we have shown how to fetch current weather data from ESP32 Arduino. This code example is basic and no JSON parsing is shown.

  • Tips For Building Digital Switch With ESP32 Arduino

    There are some design considerations to increase safety while building an ESP32 Arduino based physical switch controlled by IoT project.

  • Samsung Smartwatch as Proximity Switch : Part III

    Instead of publishing a single article on a complex matter, we split into parts. This methodology makes the thing boring to the initial readers but in the long term, the readers can browse our website and fix themselves. In the previous two parts of this topic (here is part I and here is part II), […]

  • Samsung Smartwatch as Proximity Switch : Part V [END]

    This is the final part of the series. In Part I, we talked about the basics which continued to Part II. Part III had a working code non-specific to any particular device. Part IV had a partially working code specific to a particular device. circuitdigest.com‘s code (in Part IV) was not working with Samsung Galaxy […]

Additionally, performing a search on this website can help you. Also, we have YouTube Videos.

Take The Conversation Further ...

We'd love to know your thoughts on this article.
Meet the Author over on Twitter to join the conversation right now!

If you want to Advertise on our Article or want a Sponsored Article, you are invited to Contact us.

Contact Us

Subscribe To Our Free Newsletter

Get new posts by email:

Please Confirm the Subscription When Approval Email Will Arrive in Your Email Inbox as Second Step.

Search this website…

 

Popular Articles

Our Homepage is best place to find popular articles!

Here Are Some Good to Read Articles :

  • Cloud Computing Service Models
  • What is Cloud Computing?
  • Cloud Computing and Social Networks in Mobile Space
  • ARM Processor Architecture
  • What Camera Mode to Choose
  • Indispensable MySQL queries for custom fields in WordPress
  • Windows 7 Speech Recognition Scripting Related Tutorials

Social Networks

  • Pinterest (22.1K Followers)
  • Twitter (5.8k Followers)
  • Facebook (5.7k Followers)
  • LinkedIn (3.7k Followers)
  • YouTube (1.3k Followers)
  • GitHub (Repository)
  • GitHub (Gists)
Looking to publish sponsored article on our website?

Contact us

Recent Posts

  • Application Modernization : Cloud Can Take Your Applications to the Next Level July 5, 2022
  • Ways To Make Sure Your Online Course Outshine Others July 3, 2022
  • Will Smart Factories Become the New Assembly Line? July 2, 2022
  • The Cost of Doing Business as a Handyman July 1, 2022
  • Samsung Galaxy S22 Ultra: Long Term Review June 30, 2022

About This Article

Cite this article as: Abhishek Ghosh, "Note on Calculating Distance From RSSI Value of BLE Devices," in The Customize Windows, March 18, 2020, July 5, 2022, https://thecustomizewindows.com/2020/03/note-on-calculating-distance-from-rssi-value-of-ble-devices/.

Source:The Customize Windows, JiMA.in

This website uses cookies. If you do not want to allow us to use cookies and/or non-personalized Ads, kindly clear browser cookies after closing this webpage.

Read Privacy Policy.

PC users can consult Corrine Chorney for Security.

Want to know more about us? Read Notability and Mentions & Our Setup.

Copyright © 2022 - The Customize Windows | dESIGNed by The Customize Windows

Copyright  · Privacy Policy  · Advertising Policy  · Terms of Service  · Refund Policy