Companion missions provide a path to add single-pass interferometric capabilities to existing monostatic SAR missions. Large baselines, only achievable through formation flying, are necessary both to achieve the required performance in many interferometric applications and to enable SAR tomography. Some of the main challenges include meeting tight formation flying requirements, often calling for multiple-companion solutions, and oscillator synchronization.

Companion SAR missions offer a cost-effective solution to enhance the added value of existing SAR satellites. In particular, they offer new possibilities to extend the observation space and provide one or several single-pass interferometric channels for the acquisitions. The paper aims to provide a description of an end-to-end performance simulation for companion SAR missions, including the evaluation of two exemplary configurations under realistic conditions and with the incorporation of the major error sources affecting these systems. A critical discussion of the results will be included of the final version of the paper drawing from the analysis relevant conclusions for the design of payload and concepts for future companion SAR missions.

Companion SAR missions offer a cost-effective solution to boost the performance and capabilities of existing SAR missions. In particular, a whole suite of coherent single-pass observations become feasible, allowing for the interferometric and tomographic exploitation of the received data. Interferometric and tomographic measurements are however very sensitive to even the slightest degradations in the phase of the received data, and impose stringent requirements on the calibration concept of the mission. Weakly-synchronised companion SAR missions may have significant residual clock errors, which challenge the attainment of this requirements. We put forward an innovative calibration concept based on autonomous (data-based) calibration at different product levels and present an estimation of the expected performance for ESA's SAOCOM/CS mission.

Companion SAR missions offer a cost-effective solution to boost the performance and capabilities of existing SAR missions. With the use of companion satellites, a whole suite of coherent single-pass observations become feasible, allowing for the interferometric and tomographic exploitation of the received data. Interferometric and tomographic measurements are however very sensitive to even the slightest degradations in the phase of the received data, and impose stringent requirements on the calibration concept of the mission. Weakly-synchronised companion SAR missions may have significant residual clock errors, which challenge the attainment of this requirements. We put forward an innovative calibration concept based on autonomous (data-based) calibration at different product levels and present an estimation of the expected performance for ESA's SAOCOM/CS mission.