Millimeter Wave and Terahertz Synthetic Aperture Radar for Locating Metallic Scatterers Embedded in Scattering Media

The millimetre wave (MMW) seeker can realize target detection under all weather conditions, the performance of which directly determines the design of the control algorithms. To guarantee the hitting accuracy and damaging effect of the expensive MMW guidance missile, assessing the performance of the seeker is indispensable before the launching of the missile. Real tactical environment of the seeker cannot be simulated comprehensively by indoor laboratories, and high-precision evaluation method outdoor is desperately needed. Focusing on the problem, a method for outdoor MMW seeker performance evaluation is proposed via the real-time kinematic (RTK) technology in this paper, which has the advantages of high-precision orientation and working ability under all climates. Firstly, the geometry of the seeker performance evaluation system is constructed, guaranteeing the effective working of the RTK. And then, the key parameters associated with the guidance control are calculated on the basis of the global position system (GPS) measurements. Finally, comparisons are made between the parameters obtained based on the RTK and the seeker outputs. Besides, for the performance assessment of the MMW seeker towards moving targets, a time synchronization method for different GPS carrier platforms is presented. The effectiveness of the proposed method is validated by the mooring test-fly experiments. Experimental results demonstrate that the performance of the MMW seeker can be evaluated effectively by using the proposed RTK-based method.

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“…Detailed Deduction from Equation (8) to Equation (9) In this part, we give the detail deductions from (A.1) to (A.4).…”

Section: Appendixmentioning

confidence: 99%

“…Moreover, it can be used day and night under various severe environments and climates. And the millimetre wave (MMW) seeker has been the most popular choice among all the radar seekers due to various factors such as the atmospheric attenuation and constraints between the working range and the weight [9,10].…”

Section: Introductionmentioning

confidence: 99%

Achieving Millimetre Wave Seeker Performance Evaluation Based on the Real-Time Kinematic

Chen

Liu

et al. 2020

Journal of Sensors

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“…Recently many THz SAR testbeds are proposed in the literature with focus on short-range applications in the domain of defense/security [10], [11], automobile [12], [13], non-destructive testing (NDT) [14], and indoor room profiling [15]. With electronic transceiver modules, the SAR imaging testbeds are based on radar frontends [10]- [13] and vector network analyzers (VNA) with extension modules [14]- [17]. The radar-based testbed benefit with compactness but have limited bandwidth and lower dynamic range compared to the VNA-based.…”

Section: Introductionmentioning

confidence: 99%

Short-Range SAR Imaging From GHz to THz Waves

et al. 2021

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Synthetic aperture radar (SAR) is a well-known imaging technique and most commonly used up to the microwave frequency spectrum (below 30 GHz) which provides spatial resolution in the sub-m range. To enhance the resolution, higher frequency spectra such as millimeter-wave (mmWave) and terahertz (THz) regions are being investigated. The mmWave and THz spectral ranges extend the SAR applications to nondestructive testing (NDT), material characterization, and sub-mm resolution imaging. However, the higher frequency spectrum suffers from higher path loss and potentially higher atmospheric absorption that limits the propagation distance. Nevertheless, the mmWave/THz spectrum is suitable for short-range applications such as indoor room profiling. From theoretical analysis, it can be summarized that the higher frequency spectrum provides better resolution but a comparative study on the impact on the image quality of the frequency spectrum ranging from GHz to THz has not been presented. Besides, as of the hardware complexity of the THz devices, the optimum range of the spectrum is always under investigation. The optimum range is defined where no strong improvements in the image quality are achievable with further increases in the frequency spectrum. Therefore, this paper presents an overview of electronics-based imaging using the SAR technique for the frequency spectrum ranging from GHz to THz with the focus on NDT and high-resolution imaging. Seven frequency bands: 5-10 GHz, 68-92 GHz, 75-110 GHz, 0.122-0.168 THz, 0.22-0.33 THz, 0.325-0.5 THz, and 0.85-1.1 THz are selected for a comparative analysis. The results are presented for 2D and 3D imaging using the backprojection algorithm. Additionally, state-of-the-art imaging based on SAR technique with electronics transceiver modules has only been demonstrated up to the sub-0.75 THz, whereas in this paper the spectrum up to 1.1 THz has been addressed.INDEX TERMS GHz and THz comparison, high-resolution imaging, non-destructive testing, synthetic aperture radar, terahertz imaging, radar imaging.This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination.

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“…To the best of our knowledge, the effects have not been studied for this wide bandwidth. Most of the available THz SAR testbeds are limited with the system bandwidth and follow either an ideal trajectory or equipped with high weighing IMU/INS systems that cannot be mounted on the UAV [19][20][21][22][23]. Moreover, as of the unavailability of commercial THz frontends for this wide bandwidth, a vector network analyzer (VNA) with the THz extenders is used as a radar sensor.…”

Section: Introduction and Related Workmentioning

confidence: 99%

Indoor THz SAR Trajectory Deviations Effects and Compensation With Passive Sub-mm Localization System

et al. 2020

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In radar remote sensing, the Terahertz (THz) spectrum is presently being investigated worldwide with focus on short-range indoor and outdoor applications. The spectrum broadens the unmanned aerial vehicle (UAV) based synthetic aperture radar (SAR) applications to indoor room profiling with submm resolution and material characterization as many materials have unique fingerprints at this spectrum. SAR technique requires precise localization information of the mobile radar sensor, which in conventional SAR is achieved using an existing localization infrastructure, such as a global positioning system (GPS) and inertial measurement unit (IMU). For the indoor THz SAR, the GPS does not provide coverage in indoor complex environments, and also the state-of-art compact IMU does not provide the required sub-mm accuracy. These limitations can be overcome by utilizing an indoor localization system. Therefore, this paper presents an indoor THz simultaneous localization and mapping (SLAM) system. The system comprises of passive tags based radio frequency identification (RFID) localization system and SAR that provides the UAV localization and mapping of the in-room objects. Another challenge for the UAV based indoor THz SAR that is addressed in this paper is motion compensation (MOCO). At the THz, MOCO requires special consideration due to very small trajectory deviation is in the range of carrier wavelength. Therefore, to study the effects of the sub-mm translational errors, a testbed has been set up, and measurement results are presented in this paper along with the 3D electromagnetic simulation results for a carrier frequency of 275 GHz and bandwidth of 50 GHz. Further, to compensate these errors, the sub-mm localization system is used and the results are presented to validate the proposed solution for indoor THz SAR MOCO.

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Millimeter Wave and Terahertz Synthetic Aperture Radar for Locating Metallic Scatterers Embedded in Scattering Media

Cited by 21 publications

References 16 publications

Achieving Millimetre Wave Seeker Performance Evaluation Based on the Real-Time Kinematic

Achieving Millimetre Wave Seeker Performance Evaluation Based on the Real-Time Kinematic

Short-Range SAR Imaging From GHz to THz Waves

Indoor THz SAR Trajectory Deviations Effects and Compensation With Passive Sub-mm Localization System

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