The analysis and compensation for the unwrapped phase error raised by the dynamic baseline of DSS-INSAR

The DSS-INSAR (distributed small satellite INSAR) applies the interferometry to the carrier platform which is made up of small satellites flying in a certain formation. It aims to retrieve DEM (digital elevation map) with quite high precision globally. In fact, every small satellite in the flying formation is dynamically circling around a reference central point along a certain track. Therefore, the baselines generated by the flying satellites are also unstable. However, the stability of these baselines is very crucial to get elevation measurement with high precision. Therefore, it is valuable to analyze the influences of the above-mentioned baselines on unwrapped phases. This article demonstrates the errors of unwrapped phases introduced by dynamical baselines of DSS-INSAR and provides effective solutions to compensate those errors in detail. In the first beginning, this article deduces the relationship between the across-track baseline, the along-track baseline and the orbit elements, respectively. Then, it analyzes the unwrapped phase error introduced by the dynamical baseline of DSS-INSAR. Finally, it provides a very effective model which can be used to compensate the error.