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@ARTICLE{Steinbeck:907276,
      author       = {Steinbeck, Leon and Mester, Achim and Zimmermann, Egon and
                      Klotzsche, Anja and van Waasen, Stefan},
      title        = {{I}n situ time-zero correction for a ground penetrating
                      radar monitoring system with 3000 antennas},
      journal      = {Measurement science and technology},
      volume       = {33},
      number       = {7},
      issn         = {0022-3735},
      address      = {Bristol},
      publisher    = {IOP Publ.},
      reportid     = {FZJ-2022-01938},
      pages        = {075904 -},
      year         = {2022},
      abstract     = {The time-zero correction is an essential step in the data
                      pre-processing of ground penetrating radar (GPR)
                      measurements to obtain an accurate signal propagation time
                      between transmitting and receiving antennas. For a novel
                      custom GPR monitoring system with about 3000 antennas and
                      corresponding transceiver structures placed around a soil
                      sample (lysimeter), an in situ approach for the time-zero
                      correction is required. In particular, unknown material
                      properties between any pair of transmitting and receiving
                      antennas prevent a conventional time-zero correction. We
                      present and compare two calibration approaches, namely a
                      pairwise and a mesh calibration, both utilizing the ability
                      of the monitoring system to conduct reciprocal measurements
                      between any pair of antennas. The pairwise calibration
                      enables an individual calibration for any antenna pair,
                      whereas the mesh calibration reduces the influence of the
                      soil between antenna pairs compared to the pairwise
                      calibration. The developed approach is verified by utilizing
                      a mathematical model. Experimental results from a simplified
                      setup show that the lysimeter filling has a negligible
                      impact onto the calibration approach based on adjacent
                      measurements for the mesh calibration. In addition, it is
                      shown that a state of the art time-zero calibration can be
                      used to measure the signal delays within the analog circuit
                      of the measurement system with an accuracy of ±4 ps. The
                      simulation results indicate that by using the developed
                      concept, no prior air calibration between every possible
                      antenna combination is necessary. Thus, this work provides a
                      crucial contribution towards an automated in situ time-zero
                      correction for 3D GPR monitoring systems with many
                      antennas.},
      cin          = {ZEA-2 / IBG-3},
      ddc          = {620},
      cid          = {I:(DE-Juel1)ZEA-2-20090406 / I:(DE-Juel1)IBG-3-20101118},
      pnm          = {2173 - Agro-biogeosystems: controls, feedbacks and impact
                      (POF4-217)},
      pid          = {G:(DE-HGF)POF4-2173},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000782651700001},
      doi          = {10.1088/1361-6501/ac632b},
      url          = {https://juser.fz-juelich.de/record/907276},
}