GPSrChive Discussion Forum

I contacted Garmin USA support to ask for an update on this issue, and apparently it is being worked on. No info on when to expect a software update with a fix, but at least there seems to be some progress. Fingers crossed!

Device software 5.90 seems to fix the incorrect RINEX data. I did a very quick check and I see no duplicate satellites anymore, the incorrect satellite numbers are now correct and the file also contains L5/E5a/B2 band data.

Will do some further analysis, but so far looking good!

Excellent news! We look forward to seeing some updated data!

RTKLIB 2.42 PLOT does not allow to see Beidou's Rinex files, it reads G, E, R but not C.
And yet it is well configured to see all the satellites.

You need the RTKLIB 2.43 version, on this version you can clearly see Beidou.

Can anybody provide a RINEX sample data set recorded with GPSMAP 67 / software 5.90? Ideal would be a static dual-frequency recording at a site with few obstructions for at least 15 minutes (preferably longer)? I would like to check the quality of the RINEX and of the pseudorange and carrier phase measurements themselves.

If they are significantly better than those of the 66sr, it might be worth switching to the newer product for centimeter-level positioning. I will be reporting back on my findings.

LWa wrote: Sat Sep 16, 2023 5:02 pm Can anybody provide a RINEX sample data set recorded with GPSMAP 67 / software 5.90? Ideal would be a static dual-frequency recording at a site with few obstructions for at least 15 minutes (preferably longer)? I would like to check the quality of the RINEX and of the pseudorange and carrier phase measurements themselves.

If they are significantly better than those of the 66sr, it might be worth switching to the newer product for centimeter-level positioning. I will be reporting back on my findings.

I could give you a file if you like
I turned on RINEX and left the unit in a fixed position for 15minutes. I'm unsure about 'dual frequency' do you just mean the GNSS multi-band? If so that was turned on. If you message me I can send the file over (it's at the of a big hill so it's just clear skies above).

Richard

Thank you for your offer. Unfortunately, as a newbie to this forum I am not allowed to send private messages. Can you make the data available to everyone in this forum?

The Garmin marketing describes the receiver as “multi-band”, but it supports in maximum just two frequencies per GNSS (which is good enough), i.e. it’s a dual-frequency receiver. Nowadays, professional GNSS equipment often provide observations of three signal frequencies per GNSS which is considered the real “multi-frequency”.

LWa wrote: Thu Sep 21, 2023 5:36 am Thank you for your offer. Unfortunately, as a newbie to this forum I am not allowed to send private messages. Can you make the data available to everyone in this forum?

The Garmin marketing describes the receiver as “multi-band”, but it supports in maximum just two frequencies per GNSS (which is good enough), i.e. it’s a dual-frequency receiver. Nowadays, professional GNSS equipment often provide observations of three signal frequencies per GNSS which is considered the real “multi-frequency”.

So I was at the top of a hill and put the Garmin GPSMAP67 on a rock and turned it on (RINEX loging is turned on). I wait ~17minutes then turned it off. I now realise that what I should have done is let it find its position and then turn on RINEX loging It should be OK though, you can sinply crop the first minute - I had already been using the unit on that hill so it found it's position in a few seconds. What software do you use to analyse the RINEX data?

You can contact me by email if you like

email

richard.vatax@gmail.com

RINEX Data

grmn263w41.rar

*** email address hidden to protect from web bots and scrapers

Richard's RINEX data sample of Garmin GPSMAP 67 (software version 6.60) looks quite promising.

It contains fairly complete observations, i.e. it is not as incomplete as a typical GPSMAP 66sr data set.

Dual-frequency observations are available for:
GPS - newer satellites, those which broadcast L5
Galileo
BeiDou-3

Single frequency observations for:
GPS - older satellites without L5 signals
GLONASS
BeiDou-2

The carrier-phase observations are continuous but there are very many cycle-slips esp. for frequency "5" of BeiDou.

The observations of BeiDou's 1st frequency are labeled to be of RINEX frequency "1" (1575.42 MHz). This is not correct.
In fact, the observations show that they were gathered on RINEX frequency "2" (1561.098 MHz), i.e. the RINEX file header contains a serious error.
However, this error can easily be corrected by substituting the following RINEX header line
C 8 C1X L1X D1X S1X C5X L5X D5X S5X SYS / # / OBS TYPES
by
C 8 C2X L2X D2X S2X C5X L5X D5X S5X SYS / # / OBS TYPES

Carrier-phase ambiguity fixing could not be demonstrated with this data set. Maybe the data set was just too short or other problems exist.

All these results were obtained using own software modules (WaSoft).

Thank you, Garmin software engineers have been advised!