MicroMark

MicroMark is a compact ESP32-S3 GNSS/GPS logger for coordinate recording, sample averaging, drift testing, microSD storage, CSV/DXF export, OLED display, and web-based control.

Current status

The repository currently contains experimental firmware for GNSS module testing and coordinate drift analysis.

Hardware

• ESP32-S3 Zero
• GNSS/GPS module (GT-U12 currently under MicroMark evaluation)
• SSD1306 OLED 128x64
• microSD card module
• Hardware button

Repository structure

firmware/
  experimental/
    gnss-drift-test/
  stable/
docs/
  modules/
    gt-u12/
  assets/
    gt-u12/

Experimental GNSS drift test

The current test firmware:

• records one averaged point approximately once per minute;
• averages 10 valid GNSS reports per point;
• does not filter measurements by PDOP or satellite count;
• keeps points.csv open during the drift session;
• flushes data after every saved point;
• exports CSV and DXF files;
• provides a local Wi-Fi access point and web interface.

This firmware is intended for comparing GNSS modules and measuring real coordinate drift. It is not yet the final field version of MicroMark.

GT-U12 evaluation package

MicroMark now includes a GT-U12 documentation package for module evaluation:

• photo capture manifest for required GT-U12 hardware and outdoor test photos;
• datasheet summary with MicroMark-relevant electrical and mechanical values;
• wiring notes for the ESP32-S3 Zero UART configuration;
• drift-test result template and initial bench compatibility checks.

Start with docs/modules/gt-u12/README.md and add original lab photos to docs/assets/gt-u12/ before publishing final hardware imagery.