I just spoke briefly with a colleague in Alaska, and he told me Glonass reception is a definite plus at high latitudes:
" In terms of positional accuracy GPS is slightly better than GLONASS overall, but due to the different positioning of the GLONASS satellites, GLONASS has better accuracy at high latitudes (far north or south)."
Wow.
GPS only you are typically going to receive 6-8 satellites at any given time and location. You will be very lucky to get a PDOP in the 2's. Add GLONASS, GALILEO, etc. and you will routinely have 12 or more satellites, and a PDOP in the 1's. It makes a big difference, especially in marginal conditions.
6-8 satellites is nothing to sneeze at, especially if you add 2 geostationary SBAS satellites. PDOPS under 2 only take more time, not more satellites. !0 satellites with 5 and 5 does not give you the same actual PDOP as 9-10 in one constellation. Figuring PDOP based on satellite count only is statistically fraudulent.
Paul in PA
I will be happy to put a fine point on this because I just got a call from a customer in So California at 1:30 Pacific Time who is still using GPS-Only RTK. His rover won't fix. It is stuck in FLOAT. Here is mission planning for his approximate location:
GPS Only:
Do you think that a 7.5 PDOP is an issue?
With GLO added:
And finally with GAL (GPS + GLO + GAL):
If time has no value, then you can just wait 45 minutes for the constellation to improve and then get back to work. Probably too hot to work there at 1:30 pm anyway. However, customer cut bait and went home to call and complain to me--because I control the position of the SV's in the sky and just like in the movies, I just log onto my laptop and send some more SV's his way.
I am sorry that some humans are not nice. I wish they were. I really do. Humans. Ugh.
Don't tell anyone about my ability to move the SV's around. It could turn into a full time job. But this also means that you want to stay on my good side: I can move all the SV's away from you and make it so you can't get any work done too.
Anyway, I should have also included the skyplot for that 45 minutes of high PDOP to show what occasionally happens:
5 satellites, almost one in every quadrant, all relatively high in the sky. But that makes for really hard difficult fixing.
I agree that with GPS only, when times are good it is like 'cutting butter with a red hot knife'; but when times are bad they can be really-really-really-really bad.
With GPS+GLO+GAL(+BDS) times are always great and the red hot butter knife never runs out of propane.
I have stumbled over a few more articles on the Galileo issue:
[InsideGNSS] [ Daniel Este'vez ]
The conclusion of the InsideGNSS article is spot-on:
"Perhaps the larger lesson here is that it??s not a GPS world, or a Galileo world, or a GLONASS or BeiDou world??it??s a GNSS world. And we??re all the better for it."
The Bloomberg article is also excellent, presenting a business-centric view. It points out the vulnerability of the GLONASS system to sanctions imposed by US / EUR since Ukraine.?ÿ It also puts the EU reluctance to depend on BeiDou / GPS / GLONASS on display.'
The article from Daniel Este'vez is amazing. The Pingback list at the bottom of the page is a more complete list of articles on this subject. Checkout how most of the Pings include the phrase "...Outage Serves as a Warning". Could it be that they all share the same writer / source? Probably so, since the body of the articles are identical. Each instance of this identical article has a different by-line too.
One of my take-away's from this event was the initial lack of press: evidently my personal dependence on GAL under canopy is not shared by a broad audience.?ÿ Another is the lack of transparency from the GAL Political machine.?ÿ
I am thinking that even though the GAL system is in a 'test phase', it is important for the potential future users to participate in the test. There are obvious immediate benefits to users (quick, reliable fixes under canopy) but I think the roll out of redundancy ultimately will be the largest benefit to the survey community.
I have a Leica GS18T, has Galileo progressed enough at the present to add it to my receiver. Does anyone know how much it would cost to add Galileo to my receiver?
Thanks,
Ed
If you are working in wide open sky all day, probably not worth it. If you are working under canopy and your correction source is providing GAL corrections, then yes -- get it.
No idea how much it costs to activate, we activate on everything we sell, no charge.
Thanks Mark, I like your business model a lot better than the others. I have been following your post for years.
I am locating a lot of utility poles within the road right of way and thought a few more birds would help me, I am not under canopy that much, but along side it in a 50' to 60' right of way. This may be my last big project before retirement, if I were not 71, I would definitely be giving you a call.
I will have to check to see if the NC VRS provides corrections for Galileo, maybe someone on here knows.
Thanks,
Ed
Wonder if it was the Ruskies or some other nefarious Country just testing to see if they could shut it down?
Message from GSA Executive Director, Carlo des Dorides Published:?ÿ19 July 2019
As members of the GNSS community, you are all undoubtedly aware of the recent technical incident that resulted in the temporary interruption of Galileo navigation and timing services.
The technical incident originated by an equipment malfunction in the Galileo ground infrastructure, affecting the calculation of time and orbit predictions which are used to compute the navigation message. The technical incident affected different elements of the ground facilities.
A team composed of GSA experts, industry, ESA and the Commission worked together 24/7 to address the incident, and Galileo Initial Services have now been restored. In particular, the dedication and work of our industrial partners has helped to achieve this result. Commercial users can already see signs of recovery of the Galileo navigation and timing services, although some fluctuations may be experienced until further notice.
The team is monitoring the quality of Galileo services to restore the Galileo timing and navigation services to their nominal levels. As soon as we gather all the technical elements and implement all necessary actions, we will provide more detailed information through our NAGU (Notice Advisory to Galileo Users) notifications to users.
All partners worked together to remedy the situation as soon as possible. We will set up an Independent Inquiry Board to identify the root causes of the incident. This will allow us to draw lessons for the management of a global operational system with several millions of users worldwide.
The Galileo system has grown stronger as a result of this experience, and we will continue to deliver Initial Services until full operational capability is declared. These challenging days have shown us how much you, the GNSS user community and stakeholders, rely on Galileo and how much you trust the Galileo system to deliver the services to support growth, business and sustainability. Europe and the world need a strong civil global satellite navigation system today more than ever.
https://www.gsa.europa.eu/newsroom/news/message-gsa-executive-director-carlo-des-dorides
?ÿ
