FR945 First OW Swim map problems

"It looks like you don't have access privileges to view this activity."

Sorry - try now.  

https://connect.garmin.com/modern/activity/5097583800

It seems that the watch lost GPS signal after 290 meters. The distance seems to be correct because it continued to guess the distance from accelerometer data. I guess that you stopped the measurement right after you stopped the swim, so the watch did not have the chance to add another 300m from the lost point to the end point.

Right now Garmin logic works like if it loses signal, it continues with accelerometer data, and if it finds GPS signal again, it adds the distance between the lost and found points (usually you can see it on the pace chart as a sudden pace increase jump - examples at 230 and 250m mark)

Also it can be seem that there are two constant pace during the GPS loss, 1:46 and 2:35 /100m. For me it is always 2:35, I do not understand why it jumps between this two values.

You either had an expired CPE file, what made the watch struggle to keep up with the GPS signal, or you face the current bug what Garmin has with OWS tracking. With CPE, you can refresh it by syncing with Garmin Express, or having the watch outside with GPS on for about 20 min. If you are facing the bug of sometimes the watch is not able to recover from GPS loss during a swim, I am afraid that we need to wait for Garmin to have a proper update of GPS software.

More threads about this topic:

https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-945/223160/fr945-swim-map-vs-swim-distance-gps-issue

https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-945/164018/945-appears-to-have-lost-gps-32-metres-into-open-water-swim

Thanks - really appreciate your reply, and that explanation helps.  I'll hope for the Garmin GPS fix.

Can you tell me what you mean by "having the watch outside with GPS on for about 20 min"?  I plug my watch in at night, so never really turns off.  Do you think I should let it sit outside my house before I swim?

PG said:

or you face the current bug what Garmin has with OWS tracking

What current bug? This is from my wife's 945 from the week before last. She's had similar all through Summer here. There's a lot more to OWS tracking than simply blaming the GPS - which could of course be at fault. Swim stroke is crucial and freestyle is the only stroke that will really work. Even then, there needs to be good technique to ensure the time the watch is submerged is kept to a minimum.

Yes, if the watch is new or has been recently updated then leaving it outside connected to satellites for 15 minutes plus is a good way to ensure the CPE file is updated.

If the problem persists, contact Garmin support.

Philip, face it, more and more people report the same thing here. FR945, and also Swim2 sometimes can not recover from GPS loss during (or right at the beginning) of the swim. If it does not recover, you get overinflated distance, weird map track, really weird pace chart.

Again, the nature of this bug (yes, it is a bug) is, that you might face it, or might not. Sometimes it happens, sometimes not. For me, the last 2 tracks were perfect. One track before was terrible. I swim the same technique, front crawl. FR910XT NEVER EVER made a wrong track (I have to wear it as a reference), and if it lost the GPS signal, it always recovered mid swim. Do not tell me that FR945 is a perfect watch for OWS, as it is not yet unfortunately. I tried a 945 once for OWS, it failed with the same bug (at the same swim my Swim2 on my other wrist measured a perfect track with the same software). It is interesting, that when I tried to find the cause in configuration, you told me, that if there is a fault, Garmin should correct it (aka bug). Now you say, that there is no fault, Garmin should not correct it. Please decide, and tell one thing only.

You always insert a map track as a proof of bug free software. Never a pace chart, where the symptom is really visible. You admitted once that you had about 500m over measurement. But still, you deny that you ever faced this bug. Lucky you I have to say.

And yes, Garmin support was connected, beside of me I know that some other people reported this issue to them. In an email they confirmed me that they are working on this issue.

Christian,

First check the CPE status. "About" menu item, scroll it, it will tell at one page. If it is "current", you do not need to do anything more.

If it is "expired" you can try leaving it untouched with GPS on (in this case every movement of the watch slows down the process). As default, the GPS is off, it is switched on only if you start an activity with GPS option. Unfortunately there is a timer, and if it expires, the watch automatically switches GPS off again. So in this case start an activity recording, leave it 15-20 min outside, delete the activity, check CPE status.

PG said:

You admitted once that you had about 500m over measurement. But still, you deny that you ever faced this bug. Lucky you I have to say.

Take the time to reach back through my posts on this subject. You will see that I too have reported issues with the 945 and open water swimming particularly in the early days. However, I also have reported the positive gains that Garmin have made. Unlike some who only focus on the bad. You won't have to go too far back to see comments about the difference between swim track recorded using Swimrun and OWS for instance either - reported to Garmin. I am quite happy to accept there are problems. Others seem less happy to accept suggestions that it's not always bad.

PG said:

Never a pace chart, where the symptom is really visible.

Because that's different. Pace is unlikely ever to be of relevance in a swim because of the nature of the way pace and distance are 'guesstimated' in the swim. The tracks for the swims I post reflect the distance and path swam with the overall pace as the end result. Posting pace charts adds nothing except to show where there might be periods when the signal is lost and regained - which would be expected. What is more important is that there is sufficient GPS tracking to enable a reasonable plot of the activity to be tracked. And while there might be issues with the GPS on the watch, the more likely explanation, in the absence of any thing else, is swim style.

If there is a bug, it's not widespread (does that still make it a bug?) which might suggest there is something else going on.

Argue the toss as much as you like. As long as Garmin are made aware that some people have more problems in the open water than others it can only make things better for all of us.

So report every instance to Garmin Support as well as let people know here.

I am in trouble if my stroke needs to improve for the maps to track accurately.  That doesn't seem to make sense. 

CPE is listed as "missing" in the About section.

I am swimming again tomorrow and will try to let the watch sit for a while and sync with my phone before I start. 

I am in trouble if my stroke needs to improve for the maps to track accurately.

That is the most common cause of issues when swimming in open water but if you are a good swimmer with good technique then obviously that can be ruled out. I'm a mediocre swimmer with mediocre technique but manage to get by generally.

However, before you go out next, you need/ should get that CPE file update. If it does not appear following a synch with GCM, connect and synch with Garmin Express. If that hasn't worked, and might still be a good idea anyway, sit your watch outside connected to satellites for 15 minutes plus, then check your CPE status.

Missing CPE definitely can cause such issue. To be honest, I am really surprised that the watch could keep up for about 300m without a CPE file. Make sure that next time you have a current CPE.