How do you collect a lot of data about the ionosphere? Well, you could use sounding rockets or specialized gear. Or maybe you can just conscript a huge number of cell phones. That was the approach taken by Google researchers in a recent paper in Nature.
The idea is that GPS and similar navigation satellites measure transit time of the satellite signal, but the ionosphere alters the propagation of those signals. In fact, this effect is one of the major sources of error in GPS navigation. Most receivers have an 8-parameter model of the ionosphere that reduces that error by about 50%.
However, by measuring the difference in time between signals of different frequencies, the phone can estimate the total electron current (TEC) of the ionosphere between the receiver and the satellite. This requires a dual-frequency receiver, of course.
This isn’t a new idea. There are a large number of fixed-position stations that make this measurement to contribute to a worldwide database. However, the roughly 9,000 stations can’t compete with cell phones everywhere. The paper outlines how Android smartphones can do calculations on the GPS propagation delays to report the TEC numbers.
Hams often study the ionosphere. So do sounding rockets.
That’s a very nice example of huge volumes of dirty data trumping a smaller amount of better data in the right hands.
The ‘anonymouization’ improves the statistics of the estimates. Needs a ham radio site to display the real time data.
You cannot anonymize or pseudonymize such data. Based on your workplace and home you can instantly de-anonymize every dot back to the owner of that android device. I can see why people change the stock ROM and use ROMs such as Graphene OS.
Now that’s a really good idea.
“Or maybe you can just conscript a huge number of cell phones.”
Conscript? As in using the cell phones without the owner’s consent?
Ah, but you did consent, when you clicked “allow sensor data collection for improving location accuracy”.
Ummm, NOPE, it’s not turned on along with all the other location request stuff. Wanna find me, you need to triangulate cell towers when im away from my router
If you agreed to the google maps TOS you probably already gave consent to this (and many, many, many other things)
I did not. In fact when I got my current phone, I used adb to uninstall anything google-related. Searching, e-mail and basic map viewing (when looking for a store for example) can be done using Firefox – and when I’m done I can close it and it will clear all cookies.
It’ll be covered by your advanced location services opt-in, why you don’t have to wait 10 minutes for a gps lock. Also seems to cover your phone war driving for Google, I suspect.
Thanks, was wondering why my gps didn’t work .
There was a brief moment in time where Google allowed people to search through their wardriving databases. You could punch in a MAC address, and it would geolocate to the locations it was last detected. I’m sure a lot of people had fun with that database before it stopped being publicly hosted.
Great, now Google will send me Emails with my ‘space weather history’ over the last 12 months!
Interesting thing about sensors is some are more reserved for the higher end phones. e.g. Barometer, etc.
Or just get a bunch of ham radio operators to transmit hf and vhd band, from 160 to 70cm
Get a lot of data from the ionospheric propagation
Also have radio satellite repeaters
Does SO-50 still work?
A baofeng uv5r and a diamond srh77ca antenna can reach it clear only on 5watts tx
Vhf band*
160 meters not cm
But they if you have certifications you’ll know what I’m talking about anyway 🤷♂️
Can help the auto incorrect on my phone
Can’t*. 🤷♂️
It would be interesting to do a similar study to know how happy society is by measuring how often people are having sex and the average number of partners whit whom they are having it. A side curiosity would be to see which gender is more faithful.