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Making regular GPS ultra-precise

norwegianscitechnews.com

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Re: Making regular GPS ultra-precise

#21

Post by crote »

myself248 wrote: post #11
Havoc wrote: post #3

Why don’t cities have ground beacons for this? Much cheaper than satellites and would be guaranteed to see heavy use

Some places have free RTK networks their citizens can use. Michigan's department of transportation, for instance, runs a CORS network that anyone can request access to. (At least as far as I can tell. The signup form doesn't ask for affiliation or payment.) It's just distributed over the internet, the assumption being that you probably have internet access already. One of these days I'll figure out how to set up a fr…

While we're at it, could we also broadcast navigation map updates via that FM stream?

Re: Making regular GPS ultra-precise

#22

Post by Havoc »

myself248 wrote: post #11
Havoc wrote: post #3

Why don’t cities have ground beacons for this? Much cheaper than satellites and would be guaranteed to see heavy use

Some places have free RTK networks their citizens can use. Michigan's department of transportation, for instance, runs a CORS network that anyone can request access to. (At least as far as I can tell. The signup form doesn't ask for affiliation or payment.) It's just distributed over the internet, the assumption being that you probably have internet access already. One of these days I'll figure out how to set up a fr…

Thanks - that's a lot of good info :)

Sparkfun page suggests one can do some of these adjustments via software too:

https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all

>1 cm accuracy is also possible with a few lower cost receivers (such as the NEO-M8T) by capturing raw streams from the GPS satellites and then post processing the logs with an open source program called RTKLIB.

Re: Making regular GPS ultra-precise

#23

Post by bluGill »

Precision GPS is useful for a lot of things, but not for safety. Until we equip every deer, child, and pavement heave with a GPS saying exactly where it is cars will need "something" else to detect hazards. That GPS needs to be 100% reliable, even though we cannot predict when a child will attempt to run outside naked (without their GPS position transmitter), or the pavement will decide to fail (presumably without updating the GPS).

Prevision GPS is useful for a lot of things, but it isn't needed for car navigation. If you know within 100 meters of where you are you can figure out the exact lane you are in by other clues - clues that you need to look for anyway because road/utility crews will sometimes direct you to do things that are not on your updated maps.

I couldn't read the rest of the article because that navigation bugged me too much.

Re: Making regular GPS ultra-precise

#24

Post by geerlingguy »

ktosobcy wrote: post #4
Tepix wrote: post #2

Another option to get more precise positioning is to switch from GPS to Galileo. Galileo generally offers better civilian accuracy than GPS because it uses modern signal structures with better resistance to multipath and interference and provides dual-frequency signals (E1 + E5) to all users, which mitigates ionospheric errors.

most software now uses multiple GNSS at the same time?

Usually cheaper GPS modules only do one band (L1), though. But using multiple constellations still helps a lot.

Re: Making regular GPS ultra-precise

#25

Post by myself248 »

bitbckt wrote: post #17
myself248 wrote: post #11

Earlier quoted context omitted.

Some places have free RTK networks their citizens can use. Michigan's department of transportation, for instance, runs a CORS network that anyone can request access to. (At least as far as I can tell. The signup form doesn't ask for affiliation or payment.) It's just distributed over the internet, the assumption being that you probably have internet access already. One of these days I'll figure out how to set up a fr…

Do you mean GEODNET?

Oops, indeed I do.

Re: Making regular GPS ultra-precise

#26

Post by myself248 »

Havoc wrote: post #22
myself248 wrote: post #11

Earlier quoted context omitted.

Some places have free RTK networks their citizens can use. Michigan's department of transportation, for instance, runs a CORS network that anyone can request access to. (At least as far as I can tell. The signup form doesn't ask for affiliation or payment.) It's just distributed over the internet, the assumption being that you probably have internet access already. One of these days I'll figure out how to set up a fr…

Thanks - that's a lot of good info :) Sparkfun page suggests one can do some of these adjustments via software too: https://learn.sparkfun.com/tutorials/what-is-gps-rtk/all >1 cm accuracy is also possible with a few lower cost receivers (such as the NEO-M8T) by capturing raw streams from the GPS satellites and then post processing the logs with an open source program called RTKLIB.

Post-processing is wild. Lots of detail here: https://rtkexplorer.com/

There are even cheaper raw-data receivers, this one is popular among Galmon stations: https://www.aliexpress.us/item/2251832630341954.html

Re: Making regular GPS ultra-precise

#27

Post by Luc »

crote wrote: post #20
Havoc wrote: post #3

Why don’t cities have ground beacons for this? Much cheaper than satellites and would be guaranteed to see heavy use

GPS beacons would be stupidly expensive, as you'd need tens of thousands of them per city, and each one of them would need a very accurate atomic clock. It would make far more sense (but still unviable) to go for Eurobalise-style RFID tags embedded in the road surface.

https://en.wikipedia.org/wiki/Eurobalise Cool.

Re: Making regular GPS ultra-precise

#28

Post by leecb »

eqvinox wrote: post #6

Nothing in this article is new, and the problem with RTK has always been the (unpaid) availability of reference stations. Good on them for trying to make a package of it, but maybe this "news" site could've used a bit less unchecked enthusiasm. Also, RTK is the opposite of "regular" GPS, it's generally considered a "special" usage mode of GPS. And discussing urban canyons with no mention of QZSS?

> The Quasi-Zenith Satellite System (QZSS) (Japanese: 準天頂衛星システム, Hepburn: juntenchō eisei shisutemu), also known as Michibiki (みちびき, "guidance"), is a regional navigation satellite system (RNSS) and a satellite-based augmentation system (SBAS) developed by the Japanese government to enhance the United States-operated Global Positioning System (GPS) in the Asia-Oceania regions, with a focus on Japan.

https://en.wikipedia.org/wiki/Quasi-Zenith_Satellite_System

Re: Making regular GPS ultra-precise

#29

Post by auspiv »

Havoc wrote: post #3

Why don’t cities have ground beacons for this? Much cheaper than satellites and would be guaranteed to see heavy use

The newest TV broadcast standard (ATSC 3.0) does include positioning information which is far, far, far harder to jam than GPS signals.

https://www.nab.org/bps/

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