Update GPS defaults for better accuracy across M8/M9/M10

Changed defaults to provide better out-of-box accuracy:
- gps_ublox_use_galileo: OFF → ON
- gps_ublox_use_beidou: OFF → ON
- gps_ublox_use_glonass: OFF (unchanged)
- gps_ublox_nav_hz: 10 → 8

Rationale:
- 3 constellations (GPS+Galileo+Beidou) provide excellent coverage
- 8Hz allows M9 modules to use 32 satellites (vs 16 at ≥10Hz)
- Safe for M8 (handles 8Hz easily)
- Optimal for M10 with 3 constellations at default clock
- Glonass remains OFF to avoid M10 processing overhead

Updated nav_hz description to document M9's 16-satellite
limitation at ≥10Hz, discovered through u-blox forum research
and Clive Turvey's code analysis.

Regenerated Settings.md from settings.yaml.

Related: GPS preset UI feature

Author: sensei-hacker

docs/Settings.md

@@ -1734,11 +1734,11 @@ Which SBAS mode to be used
 
 ### gps_ublox_nav_hz
 
-Navigation update rate for UBLOX receivers. Some receivers may limit the maximum number of satellites tracked when set to a higher rate or even stop sending navigation updates if the value is too high. Some M10 devices can do up to 25Hz. 10 is a safe value for M8 and newer.
+Navigation update rate for UBLOX receivers. M9 modules limit satellite tracking to 16 satellites at 10Hz or higher, but use 32 satellites below 10Hz for better accuracy. M10 modules work well at 8Hz with 3 constellations. Some M10 devices with high-performance clock can do up to 25Hz with 4 constellations. 8Hz is a safe, accurate default for M8/M9/M10.
 
 | Default | Min | Max |
 | --- | --- | --- |
-| 10 | 5 | 200 |
+| 8 | 5 | 200 |
 
 ---
 
@@ -1748,7 +1748,7 @@ Enable use of Beidou satellites. This is at the expense of other regional conste
 
 | Default | Min | Max |
 | --- | --- | --- |
-| OFF | OFF | ON |
+| ON | OFF | ON |
 
 ---
 
@@ -1758,7 +1758,7 @@ Enable use of Galileo satellites. This is at the expense of other regional const
 
 | Default | Min | Max |
 | --- | --- | --- |
-| OFF | OFF | ON |
+| ON | OFF | ON |
 
 ---
 

src/main/fc/settings.yaml

@@ -1757,12 +1757,12 @@ groups:
         type: uint8_t
       - name: gps_ublox_use_galileo
         description: "Enable use of Galileo satellites. This is at the expense of other regional constellations, so benefit may also be regional. Requires M8N and Ublox firmware 3.x (or later) [OFF/ON]."
-        default_value: OFF
+        default_value: ON
         field: ubloxUseGalileo
         type: bool
       - name: gps_ublox_use_beidou
         description: "Enable use of Beidou satellites. This is at the expense of other regional constellations, so benefit may also be regional. Requires gps hardware support [OFF/ON]."
-        default_value: OFF
+        default_value: ON
         field: ubloxUseBeidou
         type: bool
       - name: gps_ublox_use_glonass
@@ -1777,8 +1777,8 @@ groups:
         min: 5
         max: 10
       - name: gps_ublox_nav_hz
-        description: "Navigation update rate for UBLOX receivers. Some receivers may limit the maximum number of satellites tracked when set to a higher rate or even stop sending navigation updates if the value is too high. Some M10 devices can do up to 25Hz. 10 is a safe value for M8 and newer."
-        default_value: 10
+        description: "Navigation update rate for UBLOX receivers. M9 modules limit satellite tracking to 16 satellites at 10Hz or higher, but use 32 satellites below 10Hz for better accuracy. M10 modules work well at 8Hz with 3 constellations. Some M10 devices with high-performance clock can do up to 25Hz with 4 constellations. 8Hz is a safe, accurate default for M8/M9/M10."
+        default_value: 8
         field: ubloxNavHz
         type: uint8_t
         min: 5