node-red-contrib-ibeacon-kalman

A Node-RED node for iBeacon distance estimation using Kalman filtering.

Installation

npm install node-red-contrib-ibeacon-kalman

Or install via the Node-RED Palette Manager.

Features

• Converts RSSI to distance using log-distance path loss model
• Implements Kalman filtering for smooth distance estimates
• Configurable parameters:
  • TX Power (RSSI at 1m)
  • Path loss exponent (n)
  • Process noise
  • Measurement noise

Usage

1. Add the node to your flow
2. Configure the parameters:
   • TX Power: RSSI value at 1 meter distance (typically -59 dBm)
   • Path Loss Exponent: Environment factor (2.0 for free space)
   • Process Noise: How quickly the filter adapts (default 0.1)
   • Measurement Noise: RSSI measurement variance (default 1.0)

Input

• msg.payload: RSSI value in dBm (number)

Output

{
  rssi: -70,             // Input RSSI value
  rawDistance: 3.16,      // Unfiltered distance estimate
  filteredDistance: 2.87  // Kalman-filtered distance
}

Dynamic TX Power Configuration

You can override the configured TX Power per-message:

msg.txPower = -62; // dBm

When TX Power changes:

1. Kalman filter will automatically reset
2. New value will be used for distance calculation
3. Applied TX Power included in output message

Dynamic Parameters

You can override these parameters per-message:

| Parameter | Type | Default | Description | |--------------|--------|---------|----------------------------------| | txPower | number | -59 | RSSI at 1m distance (dBm) | | nValue | number | 2.0 | Path loss exponent (1.0-5.0) |

// Пример динамического изменения
msg.txPower = -62; // Для конкретного маяка
msg.nValue = 2.3;  // Для среды с препятствиями

When parameters change:

1. Kalman filter automatically resets
2. New values are used for calculations
3. All parameters included in output message

{ "payload": -65, "txPower": -58, "nValue": 3.0, "topic": "beacon/kitchen" }

License

MIT