Swipos-GIS/GEO, nationwide GNSS RTK correction for centimeter accurate location(swisstopo.admin.ch) |
Swipos-GIS/GEO, nationwide GNSS RTK correction for centimeter accurate location(swisstopo.admin.ch) |
Also, the GNSS software in most phones is sadly unable to accept the correction data from any of these systems, regardless of whether it's a nationwide network or your personal setup. This is purely a software limitation on the vendor GNSS stack, but sadly there is not enough demand for this. (An app will not fix this, we're talking vendor specific low level system code here.)
[¹] e.g. u-blox T/R series, but check specific descriptions about raw output/RTK capabilities, it changes between generations. You also want recent ones with RTCMv3, not RTCMv2.x.
I don't think that's true. Android surfaces raw GNSS measurements including carrier phase (sub wavelength measurements) to do centimeter level positioning through the raw measurements API [0].
There's even an API to specify the phone antenna phase pattern to correct the carrier phase measurements (source: I implemented it [1]). For those that aren't familiar, the idea is that the antenna pattern on phones isn't perfectly symmetrical, and depending on the direction of the incoming signal, it may appear longer. Knowing the antenna pattern, you can correct for this.
[0] https://developer.android.com/reference/android/location/Gns...
[1] https://developer.android.com/reference/android/location/Gns...
And it doesn't expose ADR/carrier phase.
I believe Google are using that themselves for their "urban canyon" GPS improvements: https://android-developers.googleblog.com/2020/12/improving-...
Or is it up to the engineer to decide how to best to use these improvements?
It's not the software, it's the hardware.
It's a bit of shame that the pricing seems to be rather steep for frivolous use, but it seems to be rather new.
It would be interesting to see what possibilities a totally free nationwide RTK system would open up.
Swisstopo is a government organization that already provides many services like highly accurate maps for free.
Goes into detail about how to setup your own, join existing networks, even using fairly inexpensive tooling for your own RTK adventures.
I am especially gratefy for his video about power measurements of microcontrollers. It's really common sense for everyone with a little bit of electronics background but I've seen so many people (some who should have known better) just sticking a multimeter onto it and calling it a day that someone really explaining patiently and in simple terms, why this often does not really work is a godsend.
https://geodesy.noaa.gov/CORS/
US overview:
https://www.arcgis.com/apps/webappviewer/index.html?id=19038...
Disclaimer: I worked on firmware on RTK radio gear.
https://medium.com/@mikehorton/what-is-a-mass-market-gnss-co...
(the USA has WAAS for aircraft)
and the fantastic opensource GPSTest app will show you what your device supports
DIY kits from the likes of (no endorsement or vouching-for implied!) SparkFun and Ardusimple prove that the actual cost of basic entry to the tech is already under $2K, and probably under $1K.
It is a valuable ability for the average person to have available, because - whether we're talking about space, or time - everything benefits from accurate measurement.
RTK correction data is mainly free in Europe, just a hassle (eg state not nationwide) and a lot of paperwork todo, that’s why a lot of commercial providers exist…
The pricing norms for RTK correction networks were set 20 years ago, when operating your own base station meant buying a second $20,000 dual frequency receiver, and taking an extra guy any time you go out to do a survey, whose job is just to guard the base station.
This made a $2000 a year network correction service seem like great value for money!
Some networks offer more affordable options these days - such as weekly and hourly licenses for drone pilots.
I feel like the marginal costs for users is so low that it would be better if it were handled as a common good like GNSS systems themselves.
https://www.maanmittauslaitos.fi/en/finpos/rtk
However, you can easily setup your own RTK base station for a few hundred bucks. Very convenient to use the free service to determine the static coordinates of your base station.
It amazes me that a country like Switzlerland only now implemented such a service, and quite expensive, nonetheless.
The corrections mentioned in the blog post are calculated by the phone (in Google Play Services, using Google's 3D building models) using the raw GNSS measurements, and provided back to the chipset to improve its position estimate (correcting for reflections and interference).
I have no affiliation, and no strong opinion on their specific approach, but I do find it interesting and have thought about running a node, especially since enjoying fiddling around with LoRa / Meshtastic.