The invention belongs to the technical field of 
bistatic synthetic aperture radar (BiSAR) transmitting and receiving, and discloses a space 
synchronizing method of a BiSAR with unknown target position coordinates. The method comprises the steps that initialization 
processing is conducted; according to a 
transmitter, the unit 
direction vector of antenna orientation is determined, the vector of a carrier coordinate 
system and the vector of a 
geographic coordinate system are converted, the vector of the 
transmitter to the center of a target area is determined, the 
geographic coordinate system and an earth coordinate 
system are converted, the vector of the 
transmitter under the earth coordinate 
system is determined, and the position vector of the center of the target area is determined; according to a 
receiver, the position vector of the 
receiver on the earth coordinate system is determined, the pointing vector of the 
receiver which points to the center of the target area is determined, the pointing vector under the 
geographic coordinate system is determined, the pointing vector under the carrier coordinate system is determined, and thus antenna orientation space synchronization of the receiver and the transmitter is achieved. The space 
synchronizing method of the BiSAR with the unknown target position coordinates has the advantages that the space 
synchronizing efficiency of the BiSAR can be effectively improved, the accuracy is high, the 
airplane mode is flexible, and the method is beneficial to being widely used.