Mark

The key word here is "Enhanced".

GPWS relies on aircraft sensors alone. Air Data, Accelerometres, and Radio Altimeters, Angle of Attack, among others. The system will compute warnings generated from those inputs. Sink rate, bank angle, to low terrain, to low flaps, glide slope..... but is rather limited in the warning envelope of items available. The is no database associated with GPWS.

EGPWS does use a database of terrain heights, buildings, antennas, etc... Lat/Long position information is usually GPS inputs.

With EGPWS the aircraft will use all of its internal sensors plus database position information to generate warnings. GPWS cannot "see" that mountain ahead. EGPWS can. EGPWS knows your heading, speed, and altitude. If your altitude is not enough to clear the mountain, it'll let you know "way" beforehand.

The phase TAWS (Terrain Awareness Warning System) can be used interchangeable with EGPWS (Enhanced Ground Proximity Warning System).