Dilution of Precision – or DOP – is an effect that reduces the accuracy of a GPS receiver’s coordinates (latitude & longitude), caused by different factors, including the angle of Earth’s satellites, atmosphere, doppler effect. For more information please see our Anti-drift Filter Tutorial.
AGPS – Assisted GPS – is a method of accelerating the time it takes the GPS Receiver to “fix” it’s latitude and longitude. The way it works is by taking assistance from GPRS and at times, the service provider network information, to pin-point the current location faster and accurately. This improves GPS availability even in cities with high buildings where the GPS conditions are bad.