Detkov A. N., Tegel S. A., Truschinski A. U.

The SAR Antenna Phase Center (APC) path is directly involved in the process of trajectory signal generation, and therefore it should be strictly defined and known beforehand along the whole synthesizing interval or measured within the UAV flight. At APC deviation by tenths of centimeters from the straight-line trajectory in the synthesizing interval there are significant phase signal distortions occurring that can substantially reduce the SAR information capacity. The nature and the intensity of these distortions greatly depend on fluctuation dispersion and their interval of random deviations correlation in the APC movement from the straight-line trajectory. This proves the fact that in turbulent atmosphere condition, the UAV SAR radar image performances are much lower than those in quiet atmosphere. The full model of APC motion trajectory is the sum of the specified nonrandom trajectory and random deviations from it. The APC trajectory model has the most sophisticated view for SAR while UAV traveling in turbulent atmosphere and carrier maneuvering. The APC radar as an UAV design point performs a compound motion that is generally composed of progressive motion along with UAV center of mass, and also APC angle deviations and linear shifts vs. center of mass as an offset point of the construction, caused by trajectory instabilities and the carrier elastic vibrations. Therefore, the use of the adaptive SAR trajectory signals processing including the APC fluctuation dynamic model with the designated flat maneuver will allow the high quality radar terrain relief images to be generated.