@misc{KahlertXuFeietal., author = {Kahlert, Moritz and Xu, Lifan and Fei, Tai and Gardill, Markus and Sun, Shunqiao}, title = {High-resolution DOA estimation using single-snapshot music for automotive radar with Mixed-ADC allocations}, series = {IEEE 13rd Sensor Array and Multichannel Signal Processing Workshop (SAM), 08-11July 2024, Corvallis, OR, USA}, journal = {IEEE 13rd Sensor Array and Multichannel Signal Processing Workshop (SAM), 08-11July 2024, Corvallis, OR, USA}, isbn = {979-8-3503-4481-3}, issn = {2151-870X}, doi = {10.1109/SAM60225.2024.10636418}, pages = {5}, abstract = {Fine direction of arrival (DOA) estimations are required for accurate target detections in automotive radar systems. To address this issue, most spectral estimation methods assume many snapshots of measurements. However, due to the dynamic nature of automotive scenarios, methods using multiple snapshots are impractical for DOA estimation in automotive radars. Furthermore, to relax the hardware requirements on modern automotive radar systems, mixed-analog-to-digital converter (ADC) allocations, i.e., the coexistence of 1-bit and high-resolution ADCs, have gained more attention recently. In this work, we introduce a high-resolution DOA estimation approach based on single-snapshot multiple signal classification (MUSIC) estimation and evaluate the performance with various ADC allocations. The results show that mixed-ADC allocations can perform comparably to high-resolution ADC allocations.}, language = {en} } @misc{KahlertFeiTebrueggeetal., author = {Kahlert, Moritz and Fei, Tai and Tebruegge, Claas and Gardill, Markus}, title = {Doppler Ambiguity Resolution for a PMCW Automotive Radar System}, series = {20th European Radar Conference (EuRAD), 20-22 September 2023, Berlin (Germany)}, journal = {20th European Radar Conference (EuRAD), 20-22 September 2023, Berlin (Germany)}, publisher = {IEEE}, isbn = {978-2-87487-074-3}, doi = {10.23919/EuRAD58043.2023.10289445}, pages = {73 -- 76}, language = {en} } @misc{KahlertFeiHirneretal., author = {Kahlert, Moritz and Fei, Tai and Hirner, Junus and Tebruegge, Claas and Gardill, Markus}, title = {Multi-Target Doppler Ambiguity Identification for a PMCW Automotive Radar System}, series = {31st European Signal Processing Conference (EUSIPCO), 04-08 September 2023, Helsinki (Finland)}, journal = {31st European Signal Processing Conference (EUSIPCO), 04-08 September 2023, Helsinki (Finland)}, publisher = {IEEE}, isbn = {978-9-4645-9360-0}, issn = {2076-1465}, doi = {10.23919/EUSIPCO58844.2023.10290009}, pages = {795 -- 799}, language = {en} } @misc{PanLiuLiuetal., author = {Pan, Mengguan and Liu, Shengheng and Liu, Peng and Qi, Wangdong and Huang, Yongming and Zheng, Wang and Wu, Qihui and Gardill, Markus}, title = {In Situ Calibration of Antenna Arrays for Positioning With 5G Networks}, series = {IEEE Transactions on Microwave Theory and Techniques}, volume = {71}, journal = {IEEE Transactions on Microwave Theory and Techniques}, number = {10}, issn = {0018-9480}, doi = {10.1109/TMTT.2023.3256532}, pages = {4600 -- 4613}, language = {en} } @misc{GardillPearsonScharnagletal., author = {Gardill, Markus and Pearson, Dominik and Scharnagl, Julian and Schilling, Klaus}, title = {Towards Wireless Ranging and Synchronization Using CubeSat Software-Defined Radio Subsystems}, series = {IEEE Space Hardware and Radio Conference, 22-25 January 2023, Las Vegas (NV, USA)}, journal = {IEEE Space Hardware and Radio Conference, 22-25 January 2023, Las Vegas (NV, USA)}, publisher = {IEEE}, isbn = {978-1-6654-9315-4}, doi = {10.1109/SHaRC56958.2023.10046143}, pages = {16 -- 19}, language = {en} } @misc{PearsonScharnaglSchillingetal., author = {Pearson, Dominik and Scharnagl, Julian and Schilling, Klaus and Gardill, Markus}, title = {Inter-Satellite Phase and Frequency Synchronization for Software-Defined CubeSat Radio Subsystems}, series = {2023 IEEE/MTT-S International Microwave Symposium : IMS : 11-16 June 2023, San Diego, California, USA}, journal = {2023 IEEE/MTT-S International Microwave Symposium : IMS : 11-16 June 2023, San Diego, California, USA}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-8-3503-4764-7}, issn = {2576-7216}, doi = {10.1109/IMS37964.2023.10188146}, pages = {287 -- 290}, language = {en} } @misc{SchmidtGardillDietl, author = {Schmidt, Marco and Gardill, Markus and Dietl, Guido}, title = {Development of a new communication payload for the educational small satellite project UWE}, series = {IAC 2023 congress proceedings, 74th International Astronautical Congress (IAC), October 2-6, 2023, Baku, Azerbaijan}, journal = {IAC 2023 congress proceedings, 74th International Astronautical Congress (IAC), October 2-6, 2023, Baku, Azerbaijan}, pages = {1}, language = {en} } @misc{AlimovHaertelBuhletal., author = {Alimov, Artem and H{\"a}rtel, Sebastian and Buhl, Johannes and Gardill, Markus and Knaack, Marcus}, title = {Erfassung von Pressen­ver­formungen mit Radarsensoren}, series = {wt Werkstattstechnik}, volume = {113}, journal = {wt Werkstattstechnik}, number = {10}, issn = {1436-4980}, doi = {10.37544/1436-4980-2023-10-47}, pages = {425 -- 431}, language = {de} } @misc{GardillValentaPrasadetal., author = {Gardill, Markus and Valenta, V{\´a}clav and Prasad, Srinivas and Quevedo-Teruel, Oscar and Ettorre, Mauro and Sauleau, Ronan}, title = {MTT-S Technical Committee Report: TC-29 on Aerospace Microwave Systems [MGA News]}, series = {IEEE Microwave Magazine}, volume = {26}, journal = {IEEE Microwave Magazine}, number = {4}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {1527-3342}, doi = {10.1109/MMM.2024.3522144}, pages = {95 -- 99}, abstract = {Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.}, language = {en} } @misc{KahlertPanFeietal., author = {Kahlert, Moritz and Pan, Jinwen and Fei, Tai and Tebruegge, Claas and Gardill, Markus}, title = {A Modular Ray Tracing-Based Framework for Automotive Radar Waveform Evaluation}, series = {IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNeT), 19-22 January 2025, San Juan, PR, USA}, journal = {IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNeT), 19-22 January 2025, San Juan, PR, USA}, isbn = {979-8-3315-0733-6}, issn = {2473-4624}, doi = {10.1109/WiSNeT63956.2025.10905020}, pages = {24 -- 27}, abstract = {Frequency-modulated continuous wave (FMCW) is the dominant waveform scheme in modern automotive radar systems used in advanced driver assistance systems (ADASs). Nevertheless, the digital modulation scheme phase-modulated continuous wave (PMCW) has recently attracted considerable interest due to advantages such as high maximum unambiguous velocities. However, there remains a need for more thorough performance assessments comparing these waveforms in dynamic automotive scenarios. This work presents a flexible framework comprising a ray-tracing simulator and radar models for efficient automotive scenario generation and radar simulation. Using this framework, the performance of FMCW and PMCW radar systems is assessed in a typical automotive scenario. The evaluation demonstrates that the PMCW radar system exhibits superior performance in terms of target detectability in the given scenario.}, language = {en} } @misc{StoecklMuellerStrandetal., author = {St{\"o}ckl, Florian and M{\"u}ller, Silvan and Strand, Marcus and Gardill, Markus}, title = {Design and evaluation of a low-cost mount for attaching a laser tracker's SMR to a robot flange}, series = {Sensors}, volume = {25}, journal = {Sensors}, number = {1}, doi = {10.3390/s25010184}, pages = {1 -- 18}, abstract = {Robot calibration and modelling measurements are commonly performed using a laser tracker. To capture three-dimensional positions, a SMR is attached to the robot. While some researchers employ adhesive bonds for this purpose, such methods often result in inaccurate, unstable and non-repeatable SMR positioning, adversely affecting measurement precision and the traceability of research outcomes. To address these challenges, we investigated alternative methods for attaching an SMR to a robot's flange to achieve both accuracy and repeatability. Additionally, we analysed measurement errors introduced when using a tool to attach the SMR to the flange. As a solution, we developed a 3D-printed mount designed for attachment to the flange. The mount's accuracy was evaluated by assessing its eccentricity and the repeatability of the SMR placement. Experimental results demonstrated that the mount achieved an eccentricity radius of 0.35 mm and repeatability inaccuracies of 𝑋=0.075mm, 𝑌=0.328mm, and 𝑍=0.485mm. These values indicate that the mount provides sufficient accuracy to support calibration processes, ensures research traceability, and serves as a viable replacement for adhesive bonds.}, language = {en} } @misc{LiuMaoLiuetal., author = {Liu, Shengheng and Mao, Zihuan and Liu, Yiran and Fei, Tai and Gardill, Markus and Huang, Yongming}, title = {TRANM: Decoherenced DoA Estimation for Automotive Radar Using Generalized Sparse Arrays}, series = {Signal Processing}, volume = {231}, journal = {Signal Processing}, publisher = {Elsevier}, doi = {10.1016/j.sigpro.2025.109895}, pages = {11}, abstract = {This paper tackles the challenge of coherent single-snapshot direction-of-arrival estimation in automotive linear frequency modulated continuous wave (LFMCW) radar using a generalized sparse array. By leveraging atomic-norm minimization (ANM)-based interpolation and Toeplitz rearrangement, a TRANM framework is proposed to address the rank-deficiency issue in the range-Doppler domain. To further enhance computational efficiency, we re-formulate the TRANM problem into an equivalent optimization with reduced dimensionality. The problem is then solved using the alternating direction method of multipliers, which provides an optimal solution via an iterative process. Numerical simulations validate that the proposed approach can accurately resolve coherent signals with improved degrees of freedom and achieve super-resolution, all while maintaining a low computational cost.}, language = {en} } @misc{KahlertFeiTebrueggeetal., author = {Kahlert, Moritz and Fei, Tai and Tebruegge, Claas and Gardill, Markus}, title = {Stepped-frequency PMCW waveforms for automotive radar applications}, series = {IEEE Transactions on Radar Systems}, volume = {3}, journal = {IEEE Transactions on Radar Systems}, issn = {2832-7357}, doi = {10.1109/TRS.2025.3528773}, pages = {233 -- 245}, abstract = {Digitally modulated radar systems, such as phase-modulated continuous-wave (PMCW), often struggle with high bandwidth demands for fine-range resolutions, posing challenges for cost-effective automotive applications. To address this issue, we propose an stepped-frequency PMCW (SF-PMCW) radar waveform in which the instantaneous bandwidth of a single pulse is extensively reduced while the range resolution is beyond the theoretical limit imposed by the instantaneous bandwidth. The proposed waveform spans a synthetic bandwidth across multiple pulses, achieving range estimates comparable to those typically achieved with higher instantaneous bandwidths. Simultaneously, the requirements for analog-to-digital converters (ADCs) are relaxed. Simulations have been performed to demonstrate the performance. The results indicate that the proposed SF-PMCW waveform with an instantaneous bandwidth of 100 MHz can achieve range estimates as good as a PMCW waveform with an instantaneous bandwidth of 1 GHz.}, language = {en} } @misc{KahlertFeiWangetal., author = {Kahlert, Moritz and Fei, Tai and Wang, Yuming and Tebruegge, Claas and Gardill, Markus}, title = {Unified model and survey on modulation schemes for next-generation automotive radar systems}, series = {Remote sensing}, volume = {17}, journal = {Remote sensing}, number = {8}, editor = {Koukiou, Georgia}, publisher = {MDPI}, address = {Basel}, issn = {2072-4292}, doi = {10.3390/rs17081355}, pages = {1 -- 43}, abstract = {Commercial automotive radar systems for advanced driver assistance systems (ADASs) have relied on frequency-modulated continuous wave (FMCW) waveforms for years due to their low-cost hardware, simple signal processing, and established academic and industrial expertise. However, FMCW systems face several challenges, including limited unambiguous velocity, restricted multiplexing of transmit signals, and susceptibility to interference. This work introduces a unified automotive radar signal model and reviews the alternative modulation schemes such as phase-coded frequency-modulated continuous wave (PC-FMCW), phase-modulated continuous wave (PMCW), orthogonal frequency-division multiplexing (OFDM), orthogonal chirp division multiplexing (OCDM), and orthogonal time frequency space (OTFS). These schemes are assessed against key technological and economic criteria and compared with FMCW, highlighting their respective strengths and limitations.}, language = {en} } @misc{JiangKnaackMartinetal., author = {Jiang, Yuyao and Knaack, Marcus and Martin, Clas Aljoscha and Tost, Frank and Alimov, Artem and H{\"a}rtel, Sebastian and Gardill, Markus}, title = {A 120 GHz industrial radar sensor network for condition monitoring of a forging process}, series = {IEEE sensors journal}, journal = {IEEE sensors journal}, publisher = {IEEE}, address = {Piscataway, NJ}, issn = {1558-1748}, doi = {10.1109/JSEN.2025.3636060}, pages = {1 -- 10}, abstract = {Current trends in forging technology emphasize increased automation and a rising demand for high-precision components. Among the key factors influencing the forging quality are process parameters, which also serve as indispensable inputs for data-driven modeling. This necessitates the establishment of a stable and robust sensor network to enable high-quality process monitoring. This study investigates the implementation of a heterogeneous sensor network within an energy-bound forging press, integrating industrial 120 GHz radar sensors for comprehensive data collection. A complete radar signal processing chain is developed, encompassing signal acquisition, pre-processing, and state estimation of the press ram. The validation against conventional reference sensors confirms the reliability and accuracy of the radar-based measurements. The results demonstrate the feasibility of the radar employment in the complex forging environment.}, language = {en} }