Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Discussion related to the Garmin GPSMAP 66sr GPSr
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GPSrChive
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by GPSrChive »

Gadwin wrote: Fri Feb 17, 2023 7:23 pm So does it mean, if I turn off Multi-band then I should receive more Galileo Satellites? Of course without Multi-band it is worse, but just out of curiosity.
Disabling Multi-Band may cause the device to track more Galileo satellites, but even then only a maximum of twelve signal bars will be displayed across the screen, the same number of signals being tracking with Multi-Band enabled in the example above.

Gadwin wrote: Fri Feb 17, 2023 7:23 pm What is the reason, that there aren't 12 GLONASS signals? I mean it is also a GNSS.
The number of tracked satellite signals depends on multiple factors, primarily the number of satellite signals available at any given time and location for the desired constellation. Trimble GNSS Planning is one of our favorite methods for viewing satellite constellation availability.

Additionally, it has been observed by many users that using 'GPS Only' frequently provides better accuracy than when using 'GPS + GLONASS'. The only reason we would enable 'GPS+GLONASS' on our Garmin devices would be if there were an insufficient number of 'GPS Only' satellite signals available and 'GPS + Galileo' was not an available option.
mimichris
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by mimichris »

Yesterday little hike I disabled the multi-band for a few minutes, the number of GPS, Galileo and Glonass satellites remains the same, with or without multi-band, the number of satellites always seems limited, Galileo the most is 7 satellites. Glonass between 5 and 7.
While on my multi-band smartphone, the number of satellites is unlimited and there are many of them, on the other hand I don't know their real efficiency.
GPSMAP66sr, GPSMAP67, GPSII+, Twonav Cross.
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GPSrChive
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by GPSrChive »

mimichris wrote: Sat Feb 18, 2023 9:05 am Yesterday little hike I disabled the multi-band for a few minutes, the number of GPS, Galileo and Glonass satellites remains the same, with or without multi-band, the number of satellites always seems limited, Galileo the most is 7 satellites. Glonass between 5 and 7.
Using the link we provided in a previous response, we were able to quickly ascertain that there were several times just today that the number of available GPS satellites would be nearly twice the number of available Galileo satellites.

Available Attachments
Available Satellites 01.png

mimichris wrote: Sat Feb 18, 2023 9:05 am While on my multi-band smartphone, the number of satellites is unlimited and there are many of them, on the other hand I don't know their real efficiency.
May be that the 'smart' phone is displaying satellites that are not actually available or visible from your current location?
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mimichris
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by mimichris »

Would the same study give the same results with 67?
GPSMAP66sr, GPSMAP67, GPSII+, Twonav Cross.
JungleJim
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by JungleJim »

mimichris wrote: Mon Apr 17, 2023 7:04 am Would the same study give the same results with 67?
With the current state of the RINEX data on the 67 with software version 4.80 I do not think it is possible to do the analysis the authors of this paper did.
Current: GPSMAP 67, Edge 1040, inReach Messenger - Previous: GPSMAP 66sr, Oregon 700, Dakota 20, Edge 1030 Plus, Edge 1030, Edge 520 Plus, Edge 520
mimichris
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by mimichris »

Indeed the RINEX file is unreadable because full of bugs. I hope it will be corrected, but for that you have to file a complaint with Garmin, I don't have a 67 so I can't do it.
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Willie
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Re: Garmin GPSMAP 66sr and Centimeter-Accurate Positioning

Unread post by Willie »

I was going to buy a 67 but the RINEX performance stopped me. I will wait until they get it right.
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