Acta Geodaetica et Cartographica Sinica ›› 2024, Vol. 53 ›› Issue (3): 473-481.doi: 10.11947/j.AGCS.2024.20220617

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A multi-baseline phase unwrapping method based on a discrete optimization framework

YUE Jiawei1, HUANG Qihuan1, LIU Hui2, MA Zhangfeng3   

  1. 1. School of Earth Sciences and Engineering, Hohai University, Nanjing 211100, China;
    2. College of Surveying and Geo-Information, North China University of Water Resources and Electric Power, Zhengzhou 450046, China;
    3. Earth Observatory of Singapore, Nanyang Technological University, Singapore 639798
  • Received:2022-10-28 Revised:2023-08-24 Published:2024-04-08
  • Supported by:
    The National Natural Science Foundation of China (Nos. 42274038; 41901411); Training Plan for Young Backbone Teachers of Colleges and Universities in Henan Province (No. 2021GGJS073); Project on Excellent Post-graduate Dissertation of Hohai University (No. 422003519)

Abstract: Multi-baseline phase unwrapping breaks through the limit of phase continuity assumption through extending the ambiguity boundary of single-baseline phase unwrapping. However, phase noise is still challenging the multi-baseline unwrapping. The clustering analysis algorithm can suppress the noise to a certain extent, but it is hard to guarantee continuity of cluster edges. In this paper, a discrete-optimization-based multi-baseline InSAR phase unwrapping algorithm is proposed, which transforms the classical multi-baseline unwrapping into a discrete optimization problem and constructs a multi-baseline unwrapping analytical framework. The method solves the phase ambiguity in the bidirectional form, and introduces block clustering to correct the abrupt change of the phase ambiguities caused by heavy noise, improving the robustness of the algorithm and overcoming the cluster boundary hopping. The effectiveness of the method has been validated through simulation and real data tests. The results show that the proposed algorithm reduces the root mean square error by about 20% compared with the traditional clustering method.

Key words: multi-baseline, InSAR phase unwrapping, discrete optimization, cluster analysis, phase continuity assumption

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