GPS:No Simulator

A research tool developed at Bochum University of Applied Sciences for simulating ESP32 devices with DW3000 UWB chip behavior.

Project Background

This simulator is part of the GPS:No research project at Bochum University of Applied Sciences focused on indoor positioning systems using Ultra-wideband (UWB) technology. It emulates data from ESP32 microcontrollers equipped with DW3000 UWB radio modules, allowing researchers to test positioning algorithms without deploying physical hardware.

Technical Approach

The simulator creates virtual instances of two device types:

• Anchor nodes with fixed positions
• Mobile tags that collect distance measurements

It calculates realistic distance data based on time-of-flight principles and publishes this information via MQTT, mirroring the behavior of actual UWB hardware. The simulation accounts for typical measurement characteristics of the DW3000 chipset including error patterns and update frequencies.

Setup and Configuration

Requirements

• Python 3.10+
• MQTT broker
• Docker (optional)

Environment Variables

MQTT Configuration

Parameter	Default	Description
MQTT_BROKER	localhost	MQTT broker hostname or IP
MQTT_PORT	1883	MQTT broker port
MQTT_USERNAME		Username for MQTT authentication
MQTT_PASSWORD		Password for MQTT authentication
MQTT_BASE_TOPIC	gpsno/simulation	Base topic for MQTT messages

Simulation Parameters

Parameter	Default	Description
UPDATE_INTERVAL	1.0	Update frequency in seconds
NUM_ANCHORS	4	Number of anchor devices
NUM_TAGS	1	Number of tag devices
SIZE_X	1000	Environment width (in units)
SIZE_Y	1000	Environment height (in units)
REALISTIC_MOVEMENT	true	Enable realistic movement patterns
DISTANCE_SCALING_FACTOR	1.0	Adjust distance measurements
REGENERATE_POSITIONS	false	Reset positions on startup
MOVEMENT_SPEED	10.0	Movement speed in units/s
TARGET_POINT_OFFSET_RADIUS	200	Random target point radius
TARGET_POINT_PROXIMITY	25.0	Distance to reach target

Storage Configuration

Parameter	Default	Description
STORAGE_TYPE	sqlite	Storage backend type
DB_PATH	data/simulation.db	Path to SQLite database file

Data Protocol

The simulator publishes data to the following MQTT topics:

{BASE_TOPIC}/devices/{DEVICE_NAME}/dev/position/x
{BASE_TOPIC}/devices/{DEVICE_NAME}/dev/position/y
{BASE_TOPIC}/devices/{DEVICE_NAME}/dev/target_point/x  # For tags
{BASE_TOPIC}/devices/{DEVICE_NAME}/dev/target_point/y  # For tags
{BASE_TOPIC}/devices/{DEVICE_NAME}/uwb/ranging         # Distance data
{BASE_TOPIC}/devices/{DEVICE_NAME}/dev/json            # Complete device state
{BASE_TOPIC}/devices/{DEVICE_NAME}/name                # Device name
{BASE_TOPIC}/devices/{DEVICE_NAME}/type                # Device type (anchor/tag)
{BASE_TOPIC}/devices/{DEVICE_NAME}/mac_address         # Device MAC address

Distance measurements are published in JSON format:

[
  {
    "mac_address": "ab:cd:ef:12:34:56",
    "distance": {
      "raw_distance": 354.6,
      "scaled_distance": 354.6
    }
  }
]

Development

Local Setup

# Clone repository
git clone https://github.com/Legincy/gps-no-simulation.git
cd gps-no-simulation

# Install dependencies
pip install -r requirements.txt

# Run simulator
python main.py

Docker Deployment

# Using docker-compose
docker-compose up -d

# Using docker directly
docker run -d --name gps-no-simulation \
  -v ./data:/app/data \
  --env-file .env \
  git.peth.pl/legincy/gps-no-simulation:latest

Research Application

This simulator supports research on:

• Indoor positioning in GPS-denied environments
• Optimization of trilateration algorithms
• Sensor fusion techniques
• Movement prediction models