Re: Digest for gpstest_android@googlegroups.com - 1 update in 1 topic
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Emilio González
Nov 6, 2023, 2:41:09 AM11/6/23
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Dear Jim,
Galileo HAS is transmitted by the Galileo satellites themselves, not through GEOs, which makes possible global coverage. Beidou has a PPP service whose corrections are broadcast through the 3 BDS-3 GEOs located at 80E, 110.5E and 140E, being thus the service regional. Today, the system does not provide ionospheric corrections so it would be theoretically possible to broadcast this message through other GEOs in the occidental region; I assume the Chinese are not willing to extend the coverage for political reasons (apart from for its cost).
Regarding using SBAS to correct several constellations, there is not enough bandwidth to cover all the current systems with the current standard. With EGNOS v3, both GPS and Galileo will be covered. To host more GNSSs, a new standard should be developed.
Best regards,
El lun, 6 nov 2023 a las 4:15, <gpstest...@googlegroups.com> escribió:
Jim bell <jimd...@gmail.com>: Nov 05 03:07PM -0800
" which means it exlusively use the 3 GEO satellites in east Asia but not
globally. "
I want to understand this. Does this mean that the Galileo HAS signal
is ONLY transmitted by GEOstationary satellites over Eurasia? And if that
is the case, does that mean that people in the Western Hemisphere can't
receive such SBAS corrections?
Well, I can understand why Europe might want to initially economize
and not yet bother to add a corrections satellite over areas that would not
be covered by Europe, but this is the first I've heard of this limitation.
I read much material about Galileo HAS weeks ago, and was VERY disappointed
to hear that virtually no smartphones supported it: I would have thought
that the HAS system woulld have been fully defined years ago (2017?) so
that the chipset manufacturers had plenty of time to incorporate it into
their chipsets.
But, I also notice that in the database of GNSS features of existing
smartphones, there seems to be a sharp cutoff at the year "2020" in the
recency of GNSS chip designs. Are those chipset manufacturers resting on
their lazy butts adding these kinds of new features?
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Emilio González
Jim bell
Nov 6, 2023, 3:08:40 AM11/6/23
to GPSTest
That's somewhat good news, at least in regards to Galileo HAS corrections. But I remain mystified why (perhaps) none of the existing smartphones can use network-broadcase corrections (IDD) for purposes of implementing HAS. Is it related to the fact that the vast majority of the smartphones listed show that the most recent era of GNSS chips are dated "2020", and not more recent? I would have hoped that the news of Galileo HAS specfication details had gotten to the GNSS-chip designers by 2017, at latest. But even if that hadn't happened, so the smartphones could not read the E6 signal, the smartphone designers should have been able to implement IDD HAS corrections.
And, is there a series of not-yet-released GNSS chips implementing the things the "2020" versions couldn't, in the works??
Invalid Data
Nov 6, 2023, 9:06:28 AM11/6/23
to GPSTest
the different between
E6 HAS: Global coverage, MEO orbit, more visibility, shorter time to receive, higher band, extra cost for hardware
B2b PPP: Region coverage, GEO orbit, less visibility, longer time to receive, similar band with L5, reduce HW cost.
L6 CLAS: Region coverage, IGSO orbit, more visibility, shorter time to receive, higher band, extra cost for hardware.
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