@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} }