Your article is good but rather focussing on technical side you are too much focussed on sales and marketing.
Most of the devices which you mentioned in your article do not have an onboard GPS Receiver as it is pretty much expensive , and if it is available at all it has its own advantages and disadvantages. GPS Fix is not available inside building , parking lots and other dense areas as GPS receiver needs to be in direct vicinity with GPS Satellites.
To overcome this limitation , Its the Network which is quite often very good in strength in dense areas , So the technology behind is AGPS (Please mind , Its a different concept here), an d is cheap . AGPS in naive language could be , say you have a phone with a capability to query network credentials (Most Smart phones have this capability), You ask your network for location . and the network knows it , it may not be accurate , and the accuracy depends upon network infrastructure. For an overview see below
GPS: Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations , GPS uses these satellites (Usually 3 or more , At least 3) as reference points to calculate positions in three dimensions: latitude, longitude, and altitude. Positions accuracy can vary from meters to a few centimeters depending upon the type of information you have access to.
AGPS : Base Station Triangulation Base station triangulation relies on measurements o
RE:RE:GPS
by Observer on Jul 20, 2008 01:01 PM Permalink
Continued....
AGPS : Base Station Triangulation Base station triangulation relies on measurements of time differences across wireless networks. AGPS uses network cell ID detection to approximate a device's position based on the coordinates of the base station it's currently using. Accuracy depends on network infrastructure (density of base station). Density is quite good in cities and GPS being not accessible from inside buildings,underground parking lots etc.
For this reason, AGPS and GPS are often used in combination.
