GPS o GPS/GLONASS

Hello:

I have a Fenix ​​6 Pro, with "GPS only" configuration and this is the question I ask you: do you notice differences between GPS and GPS/GLONASS?

I've been wearing this watch for about a month, I trailrun, swim, hike and EBike; I have made routes in outdoor activities both with GPS and with GPS / GLONASS, sunny days and very cloudy days even with rain. When I see the result on the googlemaps map in Garmin Connect, it always gives the best measurement in mode: "GPS only" and I miss that, because theoretically in mixed mode with Glonass it should have better gps reception because if any fail American GPS, it would quickly connect with a Russian one, also, that the difference in meters is less in the Russians;

The reality, in my case, is that it always gives better results in drawing the route (without going too far from the real path) in "GPS only" mode and on top of that another advantage is that "GPS only" consume less battery.

I don't understand the truth, does it happen to you too?; Garmin says that supposedly its best configuration is GPS/GLONASS but in my case it is not true, since when I go out with both modes, the map reflects huge geolocation errors, it sometimes goes more than 10 or 15 meters off the road, when in only GPS mode although it also fails, it is more accurate and it really should not be like this

I insist that I have tried very cloudy days, with rain, sun etc and it is always the same. I know that the satellites are in motion and not every day the operation in an area is the same; I also go to the website that tells you, according to geolocation, how many satellites are active in each country, but it doesn't matter, the result is always the same: GPS alone positions me much more accurately and better, it's very strange
  • GPS is imho completely sufficient.
    GPS+Glonass or Galileo can improve reception in difficult conditions such as forest, mountain or city, so can be so, but it does not have to.
    I also have the impression that "only GPS" is somewhat more accurate in the route, but is subjective and may also have been due to the respective conditions.

  • Another important problem that I have noticed is that after updating to version 24.00 with GPS 5.50, when I finish a training session, when viewing the route on the map, now on clear roads, without trees, it goes off track by about 15 meters, when with previous versions with GPS 6.60 it didn't.
    I think that the degradation has seriously impaired the reception and location
  • strange.
    there are basically 2 gps chips that are used on 6pro:

    GPS (6.xx Branch) 6.30
    GPS (5.X branch) 5.50

    The 5.50 software is for devices with a CXD5603GF and the 6.30 software is for devices with the newer CXD5605GF
    So, you can't possibly use a 5* firmware on the same watch, if your prev firmware was 6*
    or maybe I am misunderstanding something...

  • It was even worse for me on 6.6 and I now never get a true accurate tracking with either 5.5 or 6.6 since 1st October when the tracking and starting fix problems seemed to first occur.

    Now takes between 2 and 12 minutes to get an initial fix and there are always parts of a run that seem to be where the watch has lost tracking and tries to make up the gap by filling in with a sporadic track.

    This is really frustrating, the watch for racing is now really compromised as it seems a bit impractical to wait for 10 mins on the start line for the watch to work out where the hell it actually is!!

    Still no clarity from Garmin as to what happened on the 1st October, but I would be interested to know if anyone else saw a significant change in their tracking over that period?

  • or maybe I am misunderstanding something...

    Yes, you do.
    GPS FW 5xx and 6xx were merged not long ago by Garmin to version 6.60, despite different chips.
    The FW was however quickly separated again, so that with det FW24.00 has become more of a downgrade.

  • Sorry, but I have deleted the web link from the browser to see the satellites in real time according to location
    Can someone resend me the link please? I don't remember the name but I got it from this forum and it's very good. Thank you
  • I can’t say I’ve done a serious comparison, but I’ve tried the various modes and don’t notice a difference.  gps only seems as good as any of the others.  Not a lot of trees where I live tho.  Mostly clear.

  • Although with my F5+ my final choice was GPS+Glonass, with F6X GPS+Galileo works the best. Interestingly GPS+Glonass seemed to be not better than GPS only, but sometimes even worse (at low speed wandering). 1. Living in Eastern Central Europe 2. Tested it appr. a year ago.

  • los satélites están en constante movimiento, y hay que triangular tres o cuatro para poder posicionar, por eso no es posible aconsejar una opción concreta para todo el mundo; esa es la razón por la que te va mejor gps -galileo donde vives y unos días en concreto; yo en cambio con Fenix 6 Pro, Gps-Galileo en Madrid (España) me funciona peor que gps-Glonass.

    Lo que realmente he observado desde el principio es que solo la detección de GPS americano me da mejores resultados que combinada, cuando no tiene porque; 

    Con GPS "solo" el reloj solo triangula satelites Gps y con la combinación Gps-Glonass/Galileo, busca siempre Gps (solo) y si falla busca Glonass o Galileo, esa es la combinación, por lo que cuando salgo a correr en combinado, no tiene sentido que Gps-Glonass me saque del camino con más de 15 o 20 metros, no tiene lógica alguna

  • There are a lot of miss information in this forums about GNSS.

    Each constellation (GPS, Galileo, Glossnass) has 24 satellites in operation. The Fenix 5 and 6 uses L1 band (Fenix 7 uses L1 and L2) GPS bands. Beidou was never on the equation but I suspect that will be in the future and after that maybe startlink. 

    You will need at least 4 satellites to get a fix (3 for position and one for time). The satellites are always moving and sometimes the best constellation is GPS and isometimes is Galileo. Nobody knows (maybe not even Garmin) how the chipset deals with this problem.

    The problem is that Fenix5 and 6 only uses L1 and the antenna is usually facing sideways (when you are running). the implication is obvious, you will get better results riding a bike (watch facing up)   than running. Older Garmin receivers were able to use EGNOS in Europe and WAAS in US (SBAS solution) that could give great resolutions but is not present in the modern ones.

    So in F5 and F6 ,that are L1 band only, Garmin did what is a standard industry solution, it uses sensor fusion (GPS + Accelerometers) maybe (I hope) with a Kalman filter (a mathematical tool used in these situations).

    Now, there isn't any magical solution, the receivers are L1 only and when the sensor fusion works in some occasions but not in others (That's why people complain about short Km compared to reality etc).

    The best solution right now is facing the watch up ou buying a F7.