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Tomography SAR (TomoSAR) imaging can achieve three-dimensional (3D) imaging, which is significant for urban 3D mapping. When the baseline of TomoSAR is sparse, the scattering centres of several different altitudes in the same resolution unit are aliased together, which affects the accuracy of TomoSAR imaging. To solve this problem, an altitude ambiguity suppression method based on dual-frequency interfering and multi-frequency averaging is proposed. Firstly, dual-frequency interfering is used to obtain the radar cross-section (RCS) of targets and the sum of the results of the cross interference between targets and ambiguities in different positions. Then multi-frequency averaging is used to suppress the power of the cross-interference, and finally the RCS of target is accurately obtained. Simulation results verify the effectiveness of the proposed method.

We utilize an integration model of capacity degradation in electrochemical kinetics to analyze the fading characteristics of a lithium-ion battery. On the basis of the assumed parameters of the parasitic reaction, the characteristic of the lithium-ion battery are simulated before and after 100 charge–discharge cycles with the Comsol Multiphysics 4.3 software. After 100 cycles, the curves of voltage vs. state of charge under charge or discharge display a descending trend. The charge and discharge capacities decrease 8.0% and 3.85% at 1 C constant current when the cut-off voltages are set at 4.3 V and 2.8 V, respectively. In addition, the decreased capacity is related significantly to the applied current rate. By analysis, the decreased capacity due to the consumed Li + concentration by the solid-electrolyte interphase reaction is only about 0.05%, showing an extremely slight influence. Thus, the elevated film resistance plays a crucial role in decrement of the capacity. The results also display that state of charge should be set at a lower value, at least under 57%, to protect the battery from fading when it is stored for a long time.