GPS vs EXPANDED GNSS vs MULTI-BAND FREQUENCY in semi challenging conditions.

[TheATHiker]

The difference in GPS only, EXPANDED GNSS, and MULTI-BAND FREQUENCY in semi challenging conditions:

eXplore+ InReach -- GPS only (rate 30 seconds)
Fenix 7x (watch) -- EXPANDED GNSS (rate Smart)
GPSMAP 66sr -- MULTI-BAND FREQUENCY (rate 30 seconds)


First the eXplore+ InReach track GPS Only and GPSMP 66sr MULTI-BAND FREQUENCY: from Explore (web base)

Screen Shot 2022-04-21 at 1.50.30 PM.png

Next in Basecamp GPSMAP 66sr (dark trace) -- vs Fenix 7x (light trace)

Screen Shot 2022-04-21 at 2.36.51 PM.png

Next all three (the dark trace is the 66sr)

Screen Shot 2022-04-21 at 2.53.25 PM.png

This is a there and back on a logging road mountain sided to the trail head. Controlled burns closed the challenging trail hike. Location is the East mountains in Tennessee, USA.

[GPSrChive]

Thank you for posting this tracking comparison!

Of course, each of those devices has benefits and features the others do not offer.

Which do you use most?

You may also like GPSTrackEditor for simultaneous loading and display of multiple GPX files, each with unique colors.

[mimichris]

I found two tracks recorded at the same time (2022/02/30), one blue the Twonav Trail2, GPS, Galileo and Glonass, the green one, the 66sr in multi-band. The 66sr had a problem in this passage while for the rest of the hike both are completely fine.

66sr et Trail2.jpg

the same traces of the same hike in the village, both 66sr and Trail2 totally overlap.

66sr et trail2 30-01-2022.jpg

[mimichris]

Thank you for posting this tracking comparison!

Of course, each of those devices has benefits and features the others do not offer.

Which do you use most?

You may also like GPSTrackEditor for simultaneous loading and display of multiple GPX files, each with unique colors.

Gpstrackeditor does not allow me to display a satellite map and I cannot zoom the image.

[mimichris]

For me, Garmin's big mistake in this 66sr is to have put this CPE.BIN file which must be constantly updated otherwise it creates big positioning errors, why didn't it continue like the other GPS without this BIN file, it was necessary to wait a little longer for the acquisition of the satellites but it is not a problem. In fact when this file is not up to date, the GPS system does not save the almanacs as other GPS do and therefore when the reception is not very good the accuracy is worse than a GPS without multi-band like the 66s for example.

[TheATHiker]

The eXplorer inReach is by far the mostly used in backpacking . I do solo expedition backpacking 5-14 days without resupply, so power management is extremely important. that's why the inReach mini was a failure! It used more power, because you had to use the phone and the mini’s battery was really small, so you ended up taking an even larger battery then I would do with the normal InReach. A lot of my backpacking is bushwhacking that's why I added the 66 sr. I plan to use it with the explorer to help find crossings down steep ravines. The vegetation here in the southeast United States is extremely heavy so satellites are almost completely useless in determining a path through the woods.

The Fenix series (7x now ) is extremely useful in creating tracks as well as distance and other health monitoring stuff. I use it 24/7 (using the 6x while charging the 7x). One note the 7x GPS is far superior to the 6x without using multiband it's probably more superior then the 66sr in multi band mode on both. The Fenix maps are completely useless in the back country, but great in or around town for general use.

Minichris you must have a bad 66sr! or you live in a poor GPS location (high Lat). When you downloaded the last firmware did you do a hard reset plus erase? I have been using the 66sr for over 5 months and only used the computer one time to do a firmware update and download the 24k map and used the Bluetooth with the phone one time to get the tracks for comparison above. The 66sr and Fenix are all ways spot on for me. The longest unused time interval was 3 weeks for the 66sr and one trip over 1000 miles between power on with no problem. It is always spot on and sill quick! The only errors that I am getting with my old GPS is the standard drift and reflection errors and occasional drop out with multilayer vegetation, but My 66sr works inside a two story building in the center of the bottom floor which was the only time I could make the unit display only one satellite page after a few minutes the others started showing up when I got a signal from the other satellites group.

[Nail]

For me, Garmin's big mistake in this 66sr is to have put this CPE.BIN file which must be constantly updated otherwise it creates big positioning errors, why didn't it continue like the other GPS without this BIN file, it was necessary to wait a little longer for the acquisition of the satellites but it is not a problem. In fact when this file is not up to date, the GPS system does not save the almanacs as other GPS do and therefore when the reception is not very good the accuracy is worse than a GPS without multi-band like the 66s for example.

Have you tried describing this problem and submitting it to Garmin?

Today my trip was on two recorders:

Tuczno.jpg

[mimichris]

Regarding smartphones, yes they are not very good in recording traces, mine Xiaomi MI9 is multi-band (GPS L1 and L5, Galileo E1 and E5a, Glonass, Beidou), it is excellent when I record a waypoint, less than 1m of precision compared to an IGN geodetic terminal at 20cm of precision, but the trace has errors, admittedly small but it is not perfect, I think it comes from the antenna which is very small, antenna which has a primordial role on a GPS.

[GPSrChive]

For me, Garmin's big mistake in this 66sr is to have put this CPE.BIN file which must be constantly updated otherwise it creates big positioning errors, why didn't it continue like the other GPS without this BIN file, it was necessary to wait a little longer for the acquisition of the satellites but it is not a problem. In fact when this file is not up to date, the GPS system does not save the almanacs as other GPS do and therefore when the reception is not very good the accuracy is worse than a GPS without multi-band like the 66s for example.

To be very clear, this is not a good explanation of how the Garmin GPSMAP 66sr, or other Garmin devices work.

The 66sr (and many other devices) use either a CPE.BIN or EPO.BIN file to know which satellites in each constellation are available the instant the device is powered on, allowing the GPSr to find and connect with those signals almost immediately, providing a nearly instantaneous location fix.

If the CPE.BIN or EPO.BIN file has expired, the GPSr behaves as all Garmin GPSr before them, and uses manually loaded GNSS almanac information based on the devices last known location to find the most likely satellite signals available.

If the device has been moved a substantial distance (several hundred miles) since it was last powered on, or it has been powered off for a long period of time (many days or weeks), this manually loaded GNSS almanac will have to be reloaded/updated before the device can provide an accurate position, and this process can take upwards of 15 minutes, but usually less, for most modern Garmin GPSr.

Having an expired EPO/CPE files does not make your GPSr any less accurate, it just means it has to first load current GNSS almanac information the old fashioned way.

The number of satellite signals you have access to, their relative position to your location, and the obstacles in between have the greatest affect on positional accuracy.

See also:

GNSS

GPS vs GLONASS vs Galileo

[mimichris]

For having lived the experience of an outdated CPE, updating the almanacs on my 66sr is very, very long, after two hours, I do not have all the satellites visible that day and therefore the accuracy is feels.
The 66sr chipset doesn't work like other GPS's without this CPE, I'm sure.

The other Garmin GPS and other brands that I own or have owned, we wait a quarter of an hour or even less before the complete update of the satellite almanac, after which we are completely precise. Which is not the case with my 66sr or else it has a defect, but for Garmin to recognize this defect, if there is a defect, it will take months.