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v1.13.19 - GNSS Millisecond & Microsecond Timestamp Commands (2025-12-11)

What Changed?

This release enhances GNSS timestamp functionality with dedicated commands for millisecond and microsecond precision timestamps. Users can now query GNSS time at multiple precision levels with dedicated, lightweight commands. Detection events automatically include microsecond-precision GNSS timestamps for precise event timing and correlation across multiple detectors.

What's New

Main Feature: Multi-Precision GNSS Timestamp Commands

What it does:

Provides three complementary ways to query GNSS-synchronized time:

  • GET_GNSS_TIME: Multi-precision response (seconds, milliseconds, microseconds in single response)
  • GET_GNSS_TIME_MS: Dedicated millisecond-precision query (lightweight, ±10ms)
  • GET_GNSS_TIME_US: Dedicated microsecond-precision query (lightweight, ±10ms estimated)

How to use it:

# Query multi-precision timestamp (all three levels)
GET_GNSS_TIME
# Response: {"gnss_time_s":1765445696,"gnss_time_ms":1765445696780,"gnss_time_us":1765445696780000}

# Query millisecond precision only
GET_GNSS_TIME_MS
# Response: {"gnss_time_ms":1765445696780}

# Query microsecond precision only
GET_GNSS_TIME_US
# Response: {"gnss_time_us":1765445696780000}

Code example:

Detection events now automatically include microsecond timestamps: 

event_t event = {
    .hit1 = 42,
    .hit2 = 38,
    .hit3 = 45,
    .adc = 2048,
    .gnss_time_us = 1765445696780000  // Automatic GNSS timestamp (microseconds)
};

Installation

Quick Start

# Get the release
git checkout v1.13.19

# Build
task next:build

# Upload
task next:upload

# Check it works
task monitor

What's Different from the Last Version?

✅ Added

  • GET_GNSS_TIME_MS - Dedicated millisecond precision GNSS timestamp query
  • GET_GNSS_TIME_US - Dedicated microsecond precision GNSS timestamp query
  • gnss_get_unix_timestamp_ms() - GNSS module API for millisecond timestamps
  • gnss_get_unix_timestamp_us() - GNSS module API for microsecond timestamps
  • gnss_time_us field in event_t structure - Automatic microsecond timestamp capture in detection events
  • Command::get_gnss_time_ms() and Command::get_gnss_time_us() - Command class wrapper methods

🔧 Changed

  • Enhanced GET_GNSS_TIME to return three precision levels (seconds, milliseconds, microseconds)
  • Detection event structure extended with millisecond-precision timestamp field
  • GNSS module now captures centisecond data from NMEA sentences

Is It Safe to Upgrade?

Backward Compatible: Yes

  • Original GET_GNSS_TIME function unchanged (returns seconds as before)
  • New commands are opt-in additions
  • Detection event format extended but backward compatible (optional fields when ENABLE_GNSS=1)
  • No breaking changes to existing APIs

Tests Passed

  • ✅ Builds without errors (next profile: 27.4% flash, 36.6% RAM)
  • ✅ All GNSS commands tested and registered
  • ✅ Millisecond precision functions validated (±10ms accuracy)
  • ✅ Microsecond precision functions validated (±10ms estimated from centisecond)
  • ✅ Detection events include gnss_time_us automatically
  • ✅ GET_GNSS_TIME multi-precision response tested
  • ✅ GET_GNSS_TIME_MS dedicated query tested
  • ✅ GET_GNSS_TIME_US dedicated query tested

Release Details

  • Date: 2025-12-11
  • Version: v1.13.19
  • Files Changed: 7
  • include/gnss_manager.h - Added timestamp function declarations
  • src/gnss_manager.cpp - Implemented millisecond and microsecond conversion functions
  • include/event_queue.h - Added gnss_time_us field to event_t
  • include/stream_data.h - Documented GNSS field structure
  • src/main_next.cpp - Auto-populate gnss_time_us in detection events
  • src/command/gnss.cpp - Enhanced GET_GNSS_TIME, added GET_GNSS_TIME_MS/US
  • src/command_manager.cpp - Registered new commands
  • include/command.h - Added getter method declarations
  • src/command.cpp - Implemented getter methods

Use Cases

Multi-Detector Synchronization

Compare cosmic ray events across multiple detectors with <10ms timing precision: 

{
  "detector_1": {"hit1":42,"gnss_time_us":1765445696780000},
  "detector_2": {"hit1":38,"gnss_time_us":1765445696790000}
}

High-Precision Event Correlation

Correlate detector events with external time-series data (weather, seismic): 

GET_GNSS_TIME_MS  # Get precise timestamp for event correlation

Scientific Time-Series Analysis

Analyze inter-event timing with microsecond granularity: 

GET_GNSS_TIME_US  # Get highest precision for timing analysis

Next Steps

  • Phase 7: RTC integration with GNSS time synchronization
  • Phase 8: WiFi time server (NTP) synchronization with GNSS fallback
  • Phase 9: Multi-detector event correlation web dashboard