[OSM-talk] Good deal on Garmin GPS unit

[Lars Aronsson]

Nick Black wrote:

> http://www.sirf.com/Downloads/Collateral/GSC3(f)_6.20.05.pdf

If you look at the block diagram, there is nowhere that GSM 
signals are received or processed.  And judging from the 
commercial shrewdness of the telephone industry, I doubt you can 
get any useful information out of the GSM network without having a 
transmitter and a subscription (SIM card holder) too.  A GSM chip 
(receiver + transmitter) is probably more complicated than the GPS 
chip, and it would be magic if SiRF could hide all that 
functionality inside the chip which is only marginally larger than 
the old SiRFstar II.  What "GSM aided navigation" means is that a 
separate GSM unit somehow receives an approximate location and 
then enters that over the serial data line coming into the 
SiRFstar III chip.  Apparently the new chip has a new (NMEA or 
Garmin protocol) command for receiving an outside estimate of the 
location.  I think TomTom's units solve this by letting the unit 
talk to your cell phone over Bluetooth.

The GPS-GSM connection is very interesting and a bit worrying.  
It means navigation is moving from the gadget market (buy a gadget 
once, use it for free) towards the subscription market (pay per 
view).  It's the same trend as when people are scrapping their 
PDAs (gadgets) and go for more advanced cell phones (tied to 
subscriptions).  We are used to buying a GPS receiver, paying for 
it once, and then receiving the service for free, any day we want.  
But now if we want this new faster tune-in (and who wouldn't want 
that?), we need to pay mobile phone subscription charges every 
time we turn on our navigators.  The GPS system was designed by 
the same U.S. military that gave us the Internet.  If these 
systems had been designed by European telephone companies or 
indeed our national land surveys, the service (navigation and 
Internet) would not be free of charge or have flat-rate 
subscription fees.


-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se