Tuesday, June 23, 2015

Google Traffic and IMSI

On a recent trip to the east cost I did most of the driving and my sister did the navigating.  I would ask Siri for directions and she would give them for my sister to follow.  My sister has her own iPhone and once in New York I asked her to get directions.  She got them from Google but what she told me was a surprise.

She said that we could save x number of minutes by another route due to traffic congestion.  How do you know that, I asked.  She said the directions told her that and showed the length of the delay.  I said that the map directions don't have that ability.  She said yes they do and show delay on the map in red.  I asked what directions she was using.  She said Google.

News to me but when I looked I saw it was true.

Not knowing how it was done I drove on thinking that the only way they could do it was to capture an IMSI and then track it so see how it is moving.  Obviously there is a difference between 60 and 70 mph and 10 or 20.  Easy for cell phone towers to detect.  I have covered geolocation in prior posts but this was new to me.

The trip is over and a mental note was made to check on "how do they do that".

Wikipedia explains it at this link.

Yes, it involves geolocation using cell phone data location data obtained from GPS satellite positioning.  That location is transmitted to Google by Google map users.  Maybe by other Google positioning apps also?  Maybe, maybe not but why not?

The Wikipedia link specifically is about Google Traffic.  However it contains a section explaining CrowdSourcing location data to provide traffic flow info using cell phone towers for positioning.  Why include a Cell Tower crowd sourcing explanation in the explanation of how Google Maps works when Google gets its positioning from satellite GPS.  Some smoke here that indicates the presence of fire!!

From the link:

"Google Traffic works by analyzing the GPS-determined locations transmitted to them by a large number of mobile phone users. By calculating the speed of users along a stretch of road, Google is able to generate a live traffic map.[2] Google processes the incoming raw data about mobile phone device locations"

While Google obtains GPS satellite location information via their cell phone app an alternate method to obtain positioning location and deduced speed is cell towers positioning and wifi positioning.  Google does this to provide geolocation services as a Business License to app developers for a price.

It did not take much searching on Google to find the explanation, a technical one, of exactly where "Google Maps API" gets its location data from for various geolocation purposes.  Explanation at this link for Google Developers.  that buy a license from Google to use it in their apps.

I am not a Google Developer but the tech explanation of means and methods is revealing.

This section of Google Maps API geolocation explains what it is and does.  The noun and the verb nature of the API.

The Google Maps Geolocation API returns a location and accuracy radius based on information about cell towers and WiFi nodes that the mobile client can detect. This document describes the protocol used to send this data to the server and to return a response to the client.
Communication is done over HTTPS using POST. Both request and response are formatted as JSON, and the content type of both is application/json.

All this geolocation info is passively received by the cell phone from fixed transmitting source(s).  Information received is used to record/display location and associated info in real time and over time such as speed and direction calculation.  Since the "Google Map" is an on line data base, not resident data stored in the cell phone, location data has to be transmitted to a Google Map somewhere in the cloud to return display information.  I conclude that therefore there is a constant realtime communication going on between the cell phone and an external Google mapping object and function.

Ya think?

This is speculation but if logically figures because the capability exists as well as reasons to use it.

Google Maps location operates in the mode of the cell phone being the passive recipient of geograhic information transmitted by a source to it.  A cell phone also operates in an active mode transmitting identification information to a cell tower (IMSI) as well as associated meta data information that can be computed from the transmission signal.

There is a matrix point at which the passive information received by the cell phone and transmitted to Google for mapping purposes and actively transmitted information sent to a cell tower by the cell phone can be put together to identify the user association by means of the IMSI to the cell phone and its location.  Active rather than passive transmission of information about location is not only to cell towers for the purpose of cell phone communication services.  Visual information is being broadcast all the time giving a geolocation based on what is visually seen.  All that is necessary is a visual receiver such as the LPR camera at a toll booth or any other point, fixed or mobile.

Essentially, a cell tower and a video camera are simply sensor devices detecting a specific category of wave length transmission.  Some say the universe is simply just waves.  It is called wave theory.

Some App developer could create an App for sale exclusively to law enforcement agencies.  Law enforcement could buy services identifying traffic law breakers as well as identifying public safety problems.

If the State Patrol wanted to pay for it they could buy the info, which is real time, and just wait for a consistent speeder traveling at over a given rate of speed like 90 mph over a long distance and then just wait for them to go by.  No need to know the IMSI of the speeder's cell phone.  They are coming, just wait.  A blatant speeder will violate the speed limit all day long on a long trip.  Not for just a few miles.

So what is important about this?

My IMSI is identified cell tower service providers.  It tells how fast I am going.  Maybe it tells that I am on the turnpike and not moving.  My own phone is transmitting geolocation information to Google via Google maps. 

Public Safety Accident Identification:  An algorithm detects that suddenly several other vehicles are not moving on a freeway or turnpike within seconds.  Speed went from 60-70 mph or more in a matter of seconds.  Gimme a deduction.  Not much brain computing power required.  No need to call 911.  The cell phone tower service provider notifies the highway patrol.  

And if the unique IMSI is of interest to the police?  It can be tracked in real time identifying the subject of law enforcement interest with the proper legal probable cause controls having been identified.

Gone are the days where the police have to hid behind bill boards an wait for speeders to go by.  Now they can know precisely in advance based on rate of excessive speed travel.

Easy to figure out.

What intrigues me is all the other information that can be generated by IMSI cell tower recording and anonymizing the results ( or not) then data mining them.

Who is doing that now and for what purpose?

To whom exactly are the cell phone service providers selling this information and what are the recipients doing with it?

Tolls booths are an east coast thing.  Not much in the west where I live.  Each toll booth had a camera aimed at the car. Obviously LPR.  How easy is it to match an IMSI to a  license plate.  I would think that it would only require correlation between two toll booths.  They seem to be every several miles around Chicago.  Hardly get up to speed before the next one.  We finally got an EZpass.  That probably made it even easier to correlate an IMSI with an owner as well as the IMSI of each phone in the car.

The IMSI is now the identifier of the cell phone probably in the possession of the  owner (or not).

This is the Information Age.  Most people know that.  What few people know is that it is the Knowledge Age.  That is what information data becomes.  

Just driving down the highway I am creating information being recorded by sensors.  That information becomes knowledge of value to someone that will pay for it or legally demand it.  What do they do with that?  Tell me quicker ways to get to my destination.

What else?

Knowledge about me that I have no information or knowledge about.





 


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