Position variables not available/populated (@position_vertical_speed, @position_magnetic_variation); on iOS satellites info missing and “-1” values

[RastoHu]

Description

• In feature forms, the position variables @position_vertical_speed and @position_magnetic_variation are not available/populated for both internal and external GPS on Android and iOS.
• On iOS, the GPS info dialog does not show “Visible satellites” and “Used satellites”. In feature forms, satellite variables return -1 (e.g., @position_visible_satellites, @position_used_satellites).
• iOS: if External (Mock) provider is set, Horizontal accuracy and Vertical accuracy shows constant values:
  -> Horizontal accuracy: 5.00 m (constant)
  -> Vertical accuracy: 9.50 m (constant)
• Reproduced with internal GPS and with an external (mock) GNSS receiver.
• Project used: tester-ws-1/test_orthometric_heights.

Related (for context): #1743 (vertical speed), #1753 (external GNSS satellite info). Those do not cover magnetic variation nor the iOS -1 counts with internal GNSS.

Environment
PROD

Application (+ app version, build, operating system)

• Actual Android app version: 2025.6.0
• Samsung Galaxy A53 5G, Android 15
• Actual iOS app version: 2025.5.0
• iOS 18.5, iPhone

Steps to reproduce

1. Open project tester-ws-1/test_external_receiver.
2. Ensure GPS has a fix.
3. Internal GPS: add new feature in GPS_data layer; in the form, observe fields:
   • @position_vertical_speed
   • @position_magnetic_variation
   • @position_visible_satellites
   • @position_used_satellites
4. External GPS: connect an external GNSS receiver, set it as the position provider, and repeat step 3.
5. On iOS, open the GPS info dialog and verify “Visible satellites”, “Used satellites”, “Horizontal accuracy” and “Vertical accuracy”.

Actual results

• @position_vertical_speed and @position_magnetic_variation are not available/populated in the form (internal and external GPS; Android and iOS).
• iOS GPS info dialog: “Visible satellites” and “Used satellites” not shown.
• iOS GPS info dialog: “Horizontal accuracy” and “Vertical accuracy” display constant values (5.00 m/ 9.50 m).
• iOS feature form: @position_visible_satellites and @position_used_satellites evaluate to -1.

Expected results

• @position_vertical_speed and @position_magnetic_variation are available and populated when measurable (null only when not available).
• iOS GPS info dialog shows “Visible satellites” and “Used satellites”.
• iOS GPS info dialog shows “Horizontal accuracy” and “Vertical accuracy” or N/A ❓
• Satellite variables return 0 or positive counts (not -1) when a fix is available.

Screenshots or logs

Conclusion
Created by GitHub Copilot and supervised by a human test analyst.

[Withalion]

Some more info from testing: #4360