The spatial resolution of a synthetic aperture radar (SAR) system is the maximal distance between two targets, which are indistinguishable in the SAR image. SAR spatial resolution is determined individually in the two principal SAR image directions: ground range and azimuth (along-track). Ground range resolution for a SAR system is derived from slant range (across-track) resolution, by projecting it onto the ground surface using the incident angle, i.e., the angle between the line-of-sight and the ground surface normal. It is thus range-dependent, with finer resolution available in far range. Assuming adequate signal processing, slant range resolution of a SAR system is proportional to the speed of light and inversely proportional to the system bandwidth, i.e., the width of the used frequency interval. This caused by the fact that each individual frequency provides an independent measurement of the slant range, so a larger bandwidth implies more independent measurements contributing to the final slant range estimate. Similar principles apply to the azimuth direction. Assuming adequate signal processing, the SAR azimuth resolution is proportional to the along-track velocity of the SAR sensor and inversely proportional to the pulse repetition frequency (PRF) of the system. A lower interval between the consecutive pulses (higher PRF) results in better azimuth resolution due to faster sampling, but at the cost of range ambiguities occurring when echoes from one pulse are recorded after the next pulse has been transmitted.