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Indoor positioning system

This repository contains files to be used for indoor positioning platform based on Nordic Semiconductor's PCA20036 nodes.

For now, only the very basics are covered in this readme, and more detail will be added at a later time.

Requirements

  • The positioning platform
    • Nodes: PCA20036, firmware here
    • Tags: PCA10056, firmware here
    • Switch: PoE enabled Ethernet switch
  • Software
    • Python 3, tested with v3.6.4 64-bit
    • MySQL database, tested with v5.7.21
    • PacketSender to send commands to the nodes, download here

Setup

  • Physical setup
    • Connect the nodes to the switch's PoE enabled ports
    • Connect the computer to the switch
    • Optionally connect the time synchronization lines to the same external time synchronization source or let one of the nodes control the time sync signal
  • Software
    • Install Python 3
    • Data processing
      • Run pip install -r processing/requirements.txt to install required Python packages
    • Database
      • See the .sql files in the db folder folder for database and table configuration examples

Testing

Receive data from nodes

To test if receiveing data from the nodes work, do the following steps after the setup is completed:

  • Find the computer's IP address given by the switch (in the 10.0.0.x address space)
  • In a terminal, run python node_listener.py --ip <IP address>
  • Confirm that the nodes' high-power LEDs light up after a few seconds, indicating that they have received the computer's IP and port number, and are ready to track tags
  • Switch on a tag
  • See incoming scan reports in the terminal
  • Optionally enable database storing of data
    • In node_listener.py, set DB_ENABLED = True
    • Enter the preferred table name: DB_TABLE_NAME = xx
    • Insert the correct database credentials in the db.connect() function call

Apply positioning algorithm on demo data

Perform the following steps to apply a positioning algorithm to data stored in a database

  • Run the SQL query in db/create_table_positioning.sql to create a demo table
  • Extract the content of db/positioning_test_dump.zip
  • Run the SQL queries in db/positioning_test_dump.sql to populate the demo table with real test data or import the same data using the CSV file
  • In a terminal, run python processing/analysis/position_estimation.py
  • Data will be fetched from the database, and after a while a graphical representation of the indoor environment will be shown.
    • The red dots are nodes, the green es the tags true position
    • The black dot is position estimate using raw RSSI values
    • The blue is the estimate using Kalman filtered RSSI values
    • The yellow dot is the position estimate using both Kalman filtered RSSI and position

Control the nodes

The nodes have a command system installed. By sending commands to the nodes, it's possible to remotely control for instance their high-power LEDs, make a node time sync controller, change the access address for the radio, send a new IP and port for the computer, and make the nodes send who-am-I-messages.

To send command messages, import predefined commands from commands/packetsender_commands.ini into PacketSender. From PacketSender, each command can be modified and sent.

The commands are strcutured as follows

Field type Byte index Byte length Default value
Prefix 0 16 CONTROL_COMMAND:
Command 16 1
Payload length 17 1
Payload 18 -

An example of a command is to set a node as sync node. The command may look as follows in PacketSender's ASCII view: CONTROL_COMMAND:F\04\n\00\00\0c and 43 4f 4e 54 52 4f 4c 5f 43 4f 4d 4d 41 4e 44 3a 46 04 0a 00 00 0c in HEX representation. The last 4 bytes are the IP address of the node that will function as time sync controller: 10.0.0.12. Change the last byte to set any other node as controller.

A full overview of the commands is shown below

Command Defined name Payload Description
1 WHOMI_START - Starts to send WHO AM I messages containing the node’s MAC and IP every main loop iteration
2 WHOMI_STOP - Stops sending WHO AM I messages
10 CMD_SERVER_IP_BROADCAST IP:port Broadcast message from back-end computer containing IP and port for nodes to contact it
11 CMD_NEW_SERVER_IP IP_port Sent if computer obtains new IP address or changes port number
12 CMD_NEW_FIRMWARE - The node can download new firmware via TFTP
13 CMD_NEW_ACCESS_ADDRESS 6 byte address Sets new BLE access address
14 CMD_ADVERTISING_START - The nodes starts advertising
15 CMD_ADVERTISING_STOP - Stop advertising
40 CMD_ALL_HPLED_ON - Switches on all the nodes' HP LEDs
41 CMD_ALL_HPLED_OFF - Switches off all the nodes' HP LEDs
42 CMD_ALL_HPLED_DEFAULT - Sets HP LED duty cycle to default
43 CMD_ALL_HPLED_NEW_DEFAULT Units of 1/10 Sets new default HP LED duty cycle
44 CMD_ALL_HPLED_CUSTOM Units of 1/10 Sets custom HP LED duty cycle
50 CMD_SINGLE_HPLED_ON - Switches on single node's HP LED
51 CMD_SINGLE_OFF - Switches off single node's HP LED
52 CMD_SINGLE_HPLED_DEFAULT - Sets single node's HP LED to default
53 CMD_SINGLE_HPLED_CUSTOM Units of 1/10 Sets single node's HP LED to custom value
60 CMD_SINGLE_ADVERTISING_ON Single node starts advertising
61 CMD_SINGLE_ADVERTISING_OFF - Single node stops advertising
70 CMD_SYNC_NODE_SET IP address One node gets the role as synchronization signal controller
71 CMD_SYNC_SET_INTERVAL Units of 100ms Sets new synchronization signal interval