On bistatic transmitter-receiver synchronization using GPS disciplined 10 MHz oscillators

In this report, some approaches to achieve sufficient synchronization (start/stop at the same time) and syntonization (run in same pace) of the clocks (two 10 MHz oscillators) of the receiver and transmitter during bistatic SAR experiments are discussed. The main implementations investigated to realize these are:  Two free-running 10 MHz oscillators  Tw0 GPS stabilized 10 MHz oscillators  Two different types of 10 MHz oscillators, where one is free-running and the other is GPS stabilized Experimental results from such measurements are presented and discussed. Examples are also shown of monostatic and bistatic SAR images obtained at the VHF band with GPS stabilized 10 MHz oscillators in the receiver and transmitter. We conclude: Using GPS stabilized 10 MHz oscillators (Epsilon board OEM II), a phase oscillation with a periodicity of approximately 4 s (0.25 Hz) is observed. Corresponding measurements at 290 MHz in a possible bistatic configuration for the UHF band resulted in similar 0.25 Hz oscillations. This could be a potential problem for the bistatic SAR image formation, e.g. introducing geometric distortions and/or sidelobe effects. Systems simulations are needed to further evaluate such effects.