The article analyses the geometry and principle of spaceborne multistatic interferometric synthetic aperture radar (InSAR) system.It is shown that conventional method of InSAR digital elevation model (DEM) generation can not be used here

because of the features of multistatic

large squint angle and space baseline of spaceborne multistatic InSAR system.Two methods of multistatic InSAR geolocation and DEM generation are presented:one is based on Doppler-centroid equation

and the other is based on range model equation.Simulation results show that the two methods are correct.Doppler-centroid equation only makes use of range values between target and satellites

which is nearby the centre of synthetic aperture

while the range model equation can use all range values.So the method based on range model equation is more excellent than another one

which is proved by simulation results.