Software Update 2.43.8/.12 (2025 Q2)

[Pavlas]

@Egika Thank you. I’ll try to wait longer. But my process is still the same. I’ll wait for the GPS signal and get in the water. I know it’s better to wait a while. But I didn’t have any problems last year. I swim breaststroke.

[Egika]

@Pavlas then you have had exceptionally good luck in the past.

Technically the following is happening with GNSS reception:

The satellites continuously send out their position data and time stamps. The watch (with an incredibly small antenna to actually receive signals from space) tries to lock on those transmissions. It uses assumptions, where the satellites should be and which satellites to look for (from the AGPS data updates daily). Still those assumptions are just the starting point, and subsequently one after the other satellite is taken into the equation to calculate the current position. The data rate is pretty slow and the receiver needs to read the time stamps, the satellites are sending.
Position fix is possible, when a connection to 4 or 5 satellites is established. This is, when the arrow in the watch becomes green. Still, if the connection to one or more satellites is broken, the position fix will be dropped. This can easily happen if the satellite is just above the horizon, or if you move the watch antenna away facing a different direction. Thus it is crucial, that the watch is able to follow the transmissions of as many satellites as possible.
For outdoor activities usually the watch can still lock on more data streams while the activity has already started.

In the water, there is no GPS reception, as the satellite signals don’t penetrate water. This means, that the watch only has fractions of a second, to read data from the (badly positioned) antenna that has super weak signals to acquire from satellites far away in space, before it is submerged again.

You can help the process by waiting after the green arrow comes on. Green arrow means, the watch uses at least 4 satellites. Waiting longer ensures, that more satellites are added into the equation. If some are lost later, others can be used. 2-3 minutes is a good starting point.

Plus you need to bring the watch above the water level periodically for it to continue calculation your position. Breast stroke is not really suitable for this.

Conclusion: If you had good results in the past with not much waiting and swimming breaststroke, it is almost a miracle.

[Likarnik]

@nseslija sorry I can’t see power graph in your activity, how does it look? Are there drops also in fit file? So power data is wrong even when syncing to other platforms (intervals.icu for example)?

[mlakis]

Went for a training ride with power meter (Rotor INPOWER) and I can say with confidence that while riding uphill (non stop pedalling) I saw many times the power zeroing, but then on the log/SA no zeros are showing for those uphill segments.

Is this replicated?