M4JAM Jobs are either National or specific location based. If your device is A-GPS enabled, you'll be able to see and do national surveys. If your device is fully GPS enabled, you'll be able to do ALL jobs on M4JAM.
Here's what they mean:
A-GPS and GPS are different navigational aids that both use information from satellites to determine their exact location on Earth.
GPS stands for Global Positioning System. A GPS device communicates with 4 or more satellites to determine its exact location coordinates (latitude and longitude) anywhere on Earth. It works in any weather as long as the device has a clear line of sight to the satellites.
A-GPS stands for Assisted Global Positioning System. While it works on the same principles as a GPS (explained below), the difference here is that it gets the information from the satellites by using network resources e.g. mobile network, also called assistant servers.
A - GPSAssisted Global Positioning System
GPSGlobal Positioning System
|Source of triangulation information||Radio signals from satellites and assistance servers e.g. mobile network cell sites.||Radio signals from GPS satellites|
|Speed||A-GPS devices determine location coordinates faster because they have better connectivity with cell sites than directly with satellites.||GPS devices may take several minutes to determine their location because it takes longer to establish connectivity with 4 satellites.|
|Reliability||Location determined via A-GPS are slightly less accurate than GPS||GPS devices can determine location coordinates to within 1 meter accuracy|
|Cost||It costs money to use A-GPS devices on an ongoing basis because they use mobile network resources.||GPS devices communicate directly with satellites for free. There is no cost of operation once the device is paid for.|
|Usage||Mobile phones||Cars, planes, ships/boats|