Hello Garmin Team,
First of all, thank you for creating products that many of us rely on every day, often in demanding environments.
My family currently owns three Garmin watches:
- Garmin Enduro 2
- Garmin Instinct 2
- Garmin Epix (Gen 2)
Unfortunately, all three exhibit the same behavior. This is not an isolated hardware issue but a common behavior across different Garmin product lines, which strongly suggests that it is related to the firmware design rather than a defect in a specific device.
I have personally observed this issue on multiple occasions when GNSS spoofing was present. All three watches automatically accepted incorrect GNSS time, resulting in unexpected changes to the system clock and activity timestamps.
I would like to request a feature that has become increasingly important due to the widespread use of GNSS spoofing in many parts of the world.
The problem
Garmin watches currently trust GNSS as the primary source for both location and time.
When GNSS spoofing occurs, the watch may receive valid-looking but incorrect satellite data. As a result, it may automatically change:
- system time;
- time zone;
- activity timestamps.
The user has no option to prevent this behavior.
This is no longer a theoretical issue. GNSS spoofing is now common in several regions around the world, especially near conflict zones, airports, military facilities, and other sensitive locations.
Real-world consequences
For many users, the issue is far more serious than simply seeing an incorrect position on the map.
Incorrect GNSS time may cause:
- activity timestamps to become corrupted;
- FIT files to contain invalid data;
- incorrect pace and speed calculations;
- alarms and reminders to trigger at the wrong time;
- sleep and health metrics to be recorded incorrectly;
- inaccurate synchronization with Garmin Connect;
- confusion when reviewing activity history.
In my own experience, GNSS spoofing has caused sudden time changes during activities, making recorded data unreliable.
Why this happens
A spoofed GNSS signal can still appear perfectly valid to the receiver.
From the watch’s perspective:
- satellite lock is successful;
- received time appears legitimate;
- navigation solution is accepted.
The firmware therefore updates the system clock automatically, even though the received time is incorrect.
Suggested improvements
I believe this can be solved entirely in software.
1. Add an option to disable GNSS time synchronization
Allow users to receive GNSS positioning while preventing automatic clock updates.
Example:
Time Source
- Automatic
- Phone
- Internal Clock (RTC)
- GNSS
2. Detect suspicious time jumps
If GNSS reports a sudden change of several minutes or hours, treat it as suspicious rather than immediately changing the system clock.
Possible actions:
- ignore the change;
- ask for user confirmation;
- wait until the solution remains stable for a certain period;
- compare with the paired phone when available.
3. GNSS Spoofing Protection
Introduce firmware logic specifically designed to detect suspicious GNSS behavior.
Examples could include:
- sudden large changes in time;
- unrealistic position jumps;
- unexpected time zone changes;
- inconsistent satellite constellations or navigation solutions.
Even simple heuristics would significantly improve reliability.
4. Allow users to choose the preferred time source
Many users understand the risks and would gladly choose reliability over automatic synchronization.
Possible options:
- Automatic (current behavior)
- GNSS
- Phone only
- Internal RTC only
Why this matters
Garmin devices are widely used by:
- hikers;
- runners;
- cyclists;
- military personnel;
- emergency responders;
- travelers;
- professionals working in environments where GNSS interference is increasingly common.
Reliable timekeeping is just as important as accurate positioning.
Currently, users have no way to tell the watch:
“Use GNSS for positioning, but do not modify my system time.”
This feature would significantly improve the reliability of Garmin watches without requiring any hardware changes.
As a software engineer myself, I believe this is a firmware design decision rather than a hardware limitation. Even a simple validation step before accepting a large GNSS time correction would prevent many of these problems.
Thank you for considering this request. I hope Garmin will consider adding GNSS spoofing protection and giving users control over the source of time synchronization in a future firmware update.