Lightning Interferometric Processing and Uncertainty Analysis for General Noncoplanar Antenna Arrays

Shao, Xuan‐Min; Ho, Cheng; Meierbachtol, Collin S.; Anderson, Dale

doi:10.1002/essoar.10507768.1

Cited by 4 publications

(9 citation statements)

References 5 publications

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“…Although only the errors caused by the assumption of plane wave during CINTF positioning were considered when calibrating the positioning results, existing research have verified the accuracy of the CINTF used in this study [14,16]. Recently, Shao et al [32] analyzed the uncertainty of general noncoplanar antenna arrays and discussed the effect of antenna layout, radiation source location, and time error on accuracy. In the future, we will further analyze the impact of these factors on the positioning of CINTF.…”

Section: Discussionmentioning

confidence: 76%

Close Observation of the Evolution Process during Initial Stage of Triggered Lightning Based on Continuous Interferometer

et al. 2022

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The discharge signal in the initial stage of lightning is weak. The revelation of the discharge mechanism at this stage depends especially on close observation. In this study, a continuous interferometer (CINTF) was used to observe the initial stage of the upward positive leader (UPL) of the triggered lightning in Conghua District, Guangzhou City, Guangdong Province. The positioning error of CINTF for a close-range radiation source was analyzed, and the positioning error calibration method of CINTF for a specific close-range radiation source was studied, which improved the observation accuracy of elevation angle at the initial stage of the UPL of the triggered lightning. With the rise of the rocket, the positioning error in altitude during the initial stage of the UPL increased obviously. Under the layout condition of the Guangzhou field experiment site for lightning research, when the positioning results of the elevation angle of the initial stage of the UPL were 40°, 50°, and 60°, respectively, the calibrated altitude positioning error could be reduced by about 11 m, 14 m, and 20 m, respectively. On the basis of the calibrated observation results, the evolution characteristics of the initial stage of the UPL were studied, and its discharge mechanism was revealed. The precursor current pulse (PCP) was generated by a weak upward positive breakdown and a subsequent strong downward negative breakdown near the rising rocket tip, which was in the form of a single pulse. The precursor current pulse cluster (PCP cluster) and initial precursor current pulse cluster (IPCP) were both signs of self-sustaining development of the UPL. After the PCP cluster, self-sustaining development stopped immediately. The self-sustaining development after IPCP could be short-term or continuous.

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Section: Discussionmentioning

confidence: 76%

Close Observation of the Evolution Process during Initial Stage of Triggered Lightning Based on Continuous Interferometer

et al. 2022

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“…The second situation is using only two baselines produced by four non-coplanar antennas to solve Equation 7. If we have only two non-coplanar baselines, we can substitute Equation 2 into Equation 7 to get the analytical expression, as done by Shao et al (2021Shao et al ( , 2023. Here we provided another solution, which is more flexible for baseline quantities.…”

Section: Methods 2: Coordinate Rotationmentioning

confidence: 99%

“…The method proposed by Shao et al (2021Shao et al ( , 2023 can be a subset of Method 2 if we calculate using two non-coplanar baselines each time. Here, we prefer to take the weighted average of different three-antenna combinations to save calculation time.…”

Section: Comparison Between the Different Methodsmentioning

confidence: 99%

Lightning VHF Radiation Mapping Method for an Irregular Short‐Baseline Array

Yuan

Qie

Jiang

et al. 2023

Earth and Space Science

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“…This analysis has some similarities to the work of Refs. [27,28], but it includes many more (close to 400, instead of 3) antennas with baselines of up to 100 km. Since we include many more antennas the analysis is not based on the calculation of cross correlations between the antenna pairs but beamforming and an analytic calculation of error is thus precluded.…”

Section: Simulationsmentioning

confidence: 99%

“…VHF radiation is not obscured by the presence of clouds and is not attenuated in the atmosphere thus allowing for large distance observations. Radio imaging of lightning is routinely done using lightning mapping arrays [8,9] with a temporal resolution of tens of microseconds, and has recently gone through major developments with the introduction of VHF radio interferometers [10][11][12][13][14], culminating in the precision observations using the LOFAR radio telescope [15] operating in the 30-80 MHz band [16,17]. The main strength of LOFAR for lightning imaging lies in the combination of a large number of antennas (about 200 are customarily used out of about 3000 available), large baselines (up to 100 km), high timing stability (better than 10 −9 s=s), low noise level, polarization sensitivity, and the possibility for off-line analysis.…”

Section: Introductionmentioning

confidence: 99%

Interferometric imaging of intensely radiating negative leaders

et al. 2022

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The common phenomenon of lightning still harbors many secrets and only recently a new propagation mode was observed for negative leaders. While propagating in this "intensely radiating negative leader" (IRNL) mode a negative leader emits 100 times more very-high frequency (VHF) and broadband radiation than a more normal negative leader. We have reported that this mode occurs soon after initiation of all lightning flashes we have mapped as well as sometimes long thereafter. Because of the profuse emission of VHF the leader structure is very difficult to image. In this work we report on measurements made with the LOFAR radio telescope, an instrument primarily built for radio-astronomy observations. For this reason, as part of the present work, we have refined our time resolved interferometric 3-dimensional (TRI-D) imaging to take into account the antenna function. The images from the TRI-D imager show that during an IRNL there is an ionization front with a diameter in excess of 500 m where strong corona bursts occur. This is very different from what is seen for a normal negative leader where the corona bursts happen at the tip, an area of typically 10 m in diameter. The observed massive ionization wave supports the idea that this mode is indicative of a dense charge pocket.

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Lightning Interferometric Processing and Uncertainty Analysis for General Noncoplanar Antenna Arrays

Cited by 4 publications

References 5 publications

Close Observation of the Evolution Process during Initial Stage of Triggered Lightning Based on Continuous Interferometer

Close Observation of the Evolution Process during Initial Stage of Triggered Lightning Based on Continuous Interferometer

Lightning VHF Radiation Mapping Method for an Irregular Short‐Baseline Array

Interferometric imaging of intensely radiating negative leaders

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