its about airframe and SAR mode on their radar. do a little research on these aircraft from this aspect.
These vague hints, will not do, go into detail.
What exactly about the airframe?
Bars also has a synthetic aperture mode.
The one you need for nap of the earth flying, is a terrain following radar.
In Earlier days, aircrafts had to equipped with two distinct radar sets, one to look ahead and another smaller one to look down and ahead. Twin seater aircrafts were used for NOE flying, as WSO could concentrate on the terrain ahead, while the pilot flew the aircraft.
With the advent of Phased array radars, two sets of radars were not needed, and automization took enough load, that a single pilot could do the job.
In TFR mode, computer doesn't control the airplane but it gives commands to the pilot wether to climb up or down. The commands are based on the terrain and aircraft's set clearance above the ground.
Rafales , Mirages and Tornados have excellent TFR modes on their radars.
While JF-17, F-16s which have planar array radar, have no terrain following mode.
For F-16, TFR navigation is provided by an additional LANTIRN navigation and targeting pods.
No such luck for JF-17s though.
