Navigation satellite satellite-ground bistatic SAR time-frequency synchronization error estimation method and system

The invention discloses a navigation satellite satellite-ground bistatic SAR time-frequency synchronization error estimation method and system. The method comprises the steps that direct wave and reflected wave two-dimensional signals of a navigation satellite are acquired; performing distance compression on the direct wave two-dimensional signal by using a local ranging code; according to the direct wave azimuth time domain signal after distance compression, obtaining position offset caused by interference in a non-ideal sampling environment and a direct wave peak value position sequence after interference removal; correction of the ranging code is completed, and time synchronization error compensation of two-dimensional signals of direct waves and reflected waves is carried out; performing distance compression on the two-dimensional signals of the direct wave and the reflected wave after time synchronization error compensation; obtaining a direct wave peak value phase vector; performing frequency synchroniz