Add GPS preset UI with auto-detection and M9 Precision/Sport modes

[sensei-hacker]

User description

Summary

Adds GPS configuration preset system with auto-detection of GPS module type (M8/M9/M10) and optimized presets for each module. Includes educational two-preset approach for M9 modules to help users understand the accuracy vs latency trade-off.

Screenshot:

Changes

New Features

• GPS presets including auto-detection and manual settings
• Auto-detection uses hwVersion from MSP_GPSSTATISTICS (firmware PR #11262)
• M9 Precision Mode (5Hz, 32 sats, HDOP ~1.0-1.3) - default for M9
• M9 Sport Mode (10Hz, 16 sats, HDOP ~2.0-2.5) - for racing/sport
• Preset info boxes display configuration details and use cases

Files Modified

• tabs/gps.js: Added GPS_PRESETS, detectGPSPreset(), applyGPSPreset() functions
• tabs/gps.html: Added preset dropdown with 7 options
• js/msp/MSPHelper.js: Parse hwVersion from MSP_GPSSTATISTICS (backward compatible)

Preset Configurations

Preset	Rate	Constellations	Use Case
M8	8Hz	GPS+Galileo+Beidou+Glonass	Navigation, position hold
M9 Precision	5Hz	GPS+Galileo+Beidou	Long-range cruise, accuracy ✨ Default
M9 Sport	10Hz	GPS+Galileo+Beidou	Racing, acrobatics, responsiveness
M10	8Hz	GPS+Galileo+Beidou	General use, balanced
M10 High-Perf	10Hz	GPS+Galileo+Beidou+Glonass	High-performance clock only

Research & Citations

This work is based on extensive research and community contributions:

u-blox Forum Research

• M9 16-satellite limitation discovered by u-blox community expert Clive Turvey (cturvey)
• u-blox forum posts documenting 10Hz threshold:
  • https://portal.u-blox.com/s/question/0D52p00008HKEbOCAX/can-neom9n-only-use-16-satellites-with-nav-update-rate-5hz
  • https://portal.u-blox.com/s/question/0D52p00009IsVqkCAF/is-the-neom9n-limited-to-16-svs-for-the-navigation-solution
  • https://portal.u-blox.com/s/question/0D52p0000990yQ1CAI/neom9n-reduced-satellites-at-increased-rates-is-there-a-way-around-it

Clive Turvey's Code Analysis

• Documented undocumented configuration key CFG-NAVSPG-CONSTR_GNSS
• Code: https://github.com/cturvey/RandomNinjaChef/blob/main/M9_channels.c
• Shows M9 hardware enforces 16-sat limit at ≥10Hz, 32-sat below 10Hz

PX4 GPS Driver Decision

• PX4 GPS drivers chose 5Hz for M9 for better accuracy (32 satellites)
• PR discussion: u-blox: reduce update rate for M9N to 5Hz (instead of 10Hz) PX4/PX4-GPSDrivers#57
• Industry consensus: prioritize accuracy over latency for navigation

Field Testing

• Jetrell's INAV testing contributed to understanding real-world M9 behavior
• Community-reported HDOP improvements: ~1.0-1.3 at 5Hz vs ~2.0-2.5 at 10Hz

Implementation Details

Auto-Detection Logic

1. User selects "Auto-detect GPS Type" from dropdown
2. Reads FC.GPS_DATA.hwVersion from MSP_GPSSTATISTICS
3. Maps hwVersion to preset:
   • 800 (UBLOX8) → M8 preset
   • 900 (UBLOX9) → M9 Precision Mode (default)
   • 1000 (UBLOX10) → M10 preset
   • 0 (Unknown) → Falls back to Manual Settings
4. Applies preset (constellations, rate) and disables controls
5. Displays preset info box with description

Backward Compatibility

• Works with older firmware (hwVersion field check before use)
• Gracefully falls back to Manual Settings if hwVersion unavailable
• Manual preset selection always available

Testing

Tested ✅

• All presets selectable: 7 dropdown options work correctly
• M8 auto-detection: Successfully detected M8 (hwVersion=800) and applied M8 preset
• Manual presets: All 7 presets apply correct constellation/rate values
• Preset info boxes: Display correctly with descriptions
• Control disable/enable: Works correctly for presets vs manual
• Tab switching: Preserves auto-detected preset when navigating between tabs
• Backward compatibility: Older firmware without hwVersion falls back to manual

Testing Needed ⚠️

• M9 modules: Community testing needed to verify:
  • Auto-detection selects M9 Precision Mode
• M10 modules: Community testing needed to verify:
  • Auto-detection selects M10 preset

Related PR

• Firmware PR: Add GPS hardware version to MSP and optimize defaults for M8/M9/M10 inav#11262
• Firmware extends MSP_GPSSTATISTICS to include hwVersion field

Educational Value

The two M9 presets help users understand:

• Hardware limitation: M9 can only track 16 satellites at ≥10Hz
• Accuracy vs latency trade-off: 5Hz/32 sats vs 10Hz/16 sats
• HDOP impact: ~2x better accuracy at lower rate
• Flight profile matching: Choose based on aircraft type and mission

Defaults to Precision Mode (matches PX4/ArduPilot) but gives users informed choice.

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Testing help appreciated! If you have M9 or M10 modules, please test auto-detection and verify satellite counts at various rates.

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PR Type

Enhancement, New Feature

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Description

• Add GPS preset system with auto-detection for M8/M9/M10 modules

• Implement M9 Precision (5Hz) and Sport (10Hz) modes for accuracy/latency trade-off

• Expose GPS update rate control in UI with preset-based configuration

• Parse hwVersion from MSP_GPSSTATISTICS for automatic GPS module detection

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Diagram Walkthrough

flowchart LR
  A["MSP_GPSSTATISTICS<br/>hwVersion field"] -->|"Parse in<br/>MSPHelper.js"| B["FC.GPS_DATA.hwVersion"]
  B -->|"Detect GPS<br/>module type"| C["detectGPSPreset()"]
  C -->|"Map to preset<br/>M8/M9/M10"| D["GPS_PRESETS<br/>object"]
  D -->|"Apply constellation<br/>& rate settings"| E["applyGPSPreset()"]
  E -->|"Update UI<br/>& disable controls"| F["GPS Tab<br/>Configuration"]
  G["User selects<br/>preset dropdown"] -->|"Trigger change<br/>event"| E

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File Walkthrough

	Relevant files
Enhancement	MSPHelper.js Parse hwVersion from MSP_GPSSTATISTICS for auto-detection js/msp/MSPHelper.js Add backward-compatible parsing of hwVersion field from MSP_GPSSTATISTICS response Check data buffer length (>= 24 bytes) before reading hwVersion at offset 20 Set hwVersion to 0 (Unknown) for older firmware without extended MSP_GPSSTATISTICS +6/-0      gps.js Implement GPS preset detection and application logic          tabs/gps.js Define GPS_PRESETS object with 7 preset configurations (M8, M9 Precision/Sport, M10, M10 High-Perf, Manual, Auto) Implement detectGPSPreset() function to map hwVersion (800/900/1000) to appropriate preset Implement applyGPSPreset() function to apply constellation/rate settings and disable/enable controls Add preset change event handler and initialization logic that auto-detects or defaults to manual mode Display preset info box with description when preset is selected +142/-0  gps.html Add GPS preset dropdown and update rate UI controls            tabs/gps.html Add GPS preset mode dropdown with 7 options (Auto-detect, Manual, M8, M9 Precision/Sport, M10, M10 High-Perf) Add preset info display box showing preset name and configuration details Add GPS update rate number input field (previously not exposed in UI) Add IDs and preset-controlled class to constellation checkboxes for preset control Add help icons and labels for new preset and update rate controls +32/-3
Documentation	messages.json Add i18n strings for GPS preset UI elements                            locale/en/messages.json Add translation strings for GPS preset mode label and help text Add translation strings for GPS update rate label and help text Add translation strings for auto-detect success and failure messages +18/-0

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[qodo-code-review]

PR Compliance Guide 🔍

All compliance sections have been disabled in the configurations.

[Jetrell]

I loaded this software and the firmware side to give it a try. The concept seems to work as expected. Taking the guess work out of choosing a good update rate for users.

The only issue I found was after making a change to either the update rate or adding/removing a constellation other than GPS. The changes would take place. But the fields would go blank. Requiring the configurator to be restarted for the changes to appear.