Clock synchronisation for airborne bistatic SAR imaging

ONERA experimented bistatic aircraft to aircraft SAR imaging with its business jet carried system Sethi as transmitter at X-band and its motor-glider carried system BuSARd as receiver with two channels for direct and terrain scattered paths. Redundant clock synchronisation techniques were implemented: GPS disciplining, direct channel digitising, active reference transponder, bistatic autofocus and cross-platform auto-registration. Experiments with varied configurations (linear or circular acquisitions, incident angle, bistatic angle) allow to draw synchronisation technique recommendations for both experimental and operational airborne bistatic SAR.