Abstract The fundaments and computation procedures of three algorithms for SAR raw signal generation-RTPC, RFPC and 2DFFTare introduced. A quantitive comparison of these algorithms is emphatically studied on the aspects of error analysis, time and space evaluation. The simulation tests of these algorithms have been implemented using the system parameters of an X-band SAR. Both the theoretical analyses and the emulational results indicate that the third one is more practicable basing on its concise and efficient description and readability, as well as high accuracy of its result.