The hardware configuration used in this project consists of:

• Arduino UNO Q
  • Linux host (Debian-based)
  • STM32F0 microcontroller
• RTL-SDR front-end
  • Nooelec NESDR SmarTee SDR
• Active GNSS antenna
• LED matrix display driven by the STM32F0 MCU

Real-time GNSS processing is performed using the following configuration:

• Constellation: GPS
• Signal: GPS L1 C/A
• Number of tracking channels: 7
• Coherent integration time: 4 ms
• Front-end: RTL-SDR (live RF input)

The receiver computes standard GNSS outputs in real time, including:

• GPS observables
• Carrier-to-noise density ratio (C/N₀)
• Position, Velocity, and Time (PVT) solution

Galileo signal processing is currently not enabled due to platform resource limitations.

A dedicated Python script extracts relevant GNSS-SDR outputs and forwards them to the STM32F0 microcontroller on the Arduino UNO Q.

The microcontroller drives an LED matrix display, providing real-time visualization of receiver status and navigation parameters.

Currently visualized information includes:

• Satellite signal strength indicators (C/N₀)
• Receiver activity and status
• PVT-related information

The LED matrix provides a compact, color-coded visualization of key PVT parameters:

• Red: A binary clock indicating the number of tracked satellites. The most significant bit is the leftmost LED.
• Purple: A conventional PVT status indicator. It blinks when no solution is available, remains steadily lit at low intensity for a 2D fix, and steadily lit at higher intensity for a 3D fix.
• Yellow: C/N₀ bar indicators for up to seven satellites.
• Green: Position and velocity representation. Within this square, a dot moves in the corresponding direction of motion; its displacement increases or decreases proportionally with the platform’s speed.

A Node.js-based web server runs on the Linux side of the Arduino UNO Q and provides a browser-accessible interface to control GNSS-SDR execution. The web interface allows the user to: Start and stop the GNSS-SDR receiver Select between different GNSS-SDR configuration filesOffline / post-processing configuration Real-time configuration using RTL-SDR Selected GNSS-SDR outputs (observables, C/N₀, and PVT) are exposed for monitoring and downstream processing.