Concept and Implementation of a PLL-Controlled Interlaced Chirp Sequence Radar for Optimized Range–Doppler Measurements

Thurn, Karsten; Shmakov, Denys; Li, Gang; Max, S.; Meinecke, Marc-Michael; Vossiek, Martin

doi:10.1109/tmtt.2016.2599875

Cited by 23 publications

(13 citation statements)

References 18 publications

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“…Such a set-up is common in the time division multiplexing scheme, which is widely used to obtain the orthogonality between multiple transmitters. In the following section, we demonstrate that the proposed network can resolve the velocity ambiguity problem without hardware changes (e.g., overlapping elements [42]), changes in the transmission scheme (e.g., frequency shift [43], [44]), or additional signal processing steps [45].…”

Section: A Data Acquisitionmentioning

confidence: 94%

Complex-Valued Channel Attention and Application in Ego-Velocity Estimation With Automotive Radar

et al. 2021

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Attention mechanisms have been widely integrated with various neural networks to boost performance. However, when an attention mechanism was applied to a radar ego-velocity estimation network, the importance of carefully handling the amplitude and phase of complex-valued tensor was revealed. Therefore, in this study, we present a self-attention mechanism designed to handle complexvalued tensors in order to capture the rich contextual relationships implied within amplitude and phase. To exploit the advantages of complex-valued attention (CA), we evaluated its impact while performing egovelocity estimation tasks based on radar data, whose amplitude and phase are related to the electromagnetic scattering of the target being observed. Radars are suitable sensors for such tasks as they are capable of long-range detection and instantaneous velocity measurement under variable weather and lighting conditions. In particular, we coupled our CA module with complex-valued neural networks, known to be particularly powerful for handling wave phenomena. The proposed method exhibits robust estimation performance, regardless of whether the Doppler ambiguity problem occurs and eliminates the dependence on preprocessing stages, including target detection and static target indication. Furthermore, it achieves improved stability during training via geometrical constraint regularization, and implicitly allows velocity conversion between the sensor and vehicle frames, even if the mount information of the sensor was not provided. Finally, ablation experiments conducted on extensive real-world datasets show noticeable improvement in estimation performance. INDEX TERMS Automotive radar; complex-valued attention; complex-valued neural network; deep learning; ego-velocity estimation This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

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Section: A Data Acquisitionmentioning

confidence: 94%

Complex-Valued Channel Attention and Application in Ego-Velocity Estimation With Automotive Radar

et al. 2021

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“…One possibility for an adaption of the modulation format is to alter the repetition times in consecutive measurements and apply the Chinese remainder theorem (CRT ) [33]. Other authors suggest adapting the modulation format using the interlaced chirp-sequence approach as presented in [35,36]. The basic idea is that consecutive frequency ramps have increasing centre frequencies.…”

Section: Enhancing the Unambiguous Doppler Velocitymentioning

confidence: 99%

Radar Sensors for Autonomous Driving: Modulation Schemes and Interference Mitigation

Roos¹,

Bechter²,

Knill³

et al. 2019

IEEE Microwave

145

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“…In addition, since each Tx antenna transmits a signal alternately, the Doppler effect caused by the movement of the target can degrade the angle estimation performance [12], [13]. To address these issues, several studies have attempted to solve the Doppler-angle ambiguity of the TDM-MIMO radar system [14], [15]. In [14], the conventional chirp sequence was modified to assign a different starting frequency for each chirp.…”

Section: Introductionmentioning

confidence: 99%

“…To address these issues, several studies have attempted to solve the Doppler-angle ambiguity of the TDM-MIMO radar system [14], [15]. In [14], the conventional chirp sequence was modified to assign a different starting frequency for each chirp. Similarly, in [15], multiple chirp repetition frequencies were assigned and the original maximum detectable velocity was recovered using the Chinese remainder theorem.…”

Section: Introductionmentioning

confidence: 99%

Solving Doppler-Angle Ambiguity of BPSK-MIMO FMCW Radar System

et al. 2021

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In a multiple-input multiple-output (MIMO) radar system, binary phase-shift keying (BPSK) modulation is widely used to separate signals transmitted from multiple transmit (Tx) antennas. However, when the BPSK modulation is applied to the frequency-modulated continuous-wave (FMCW) radar system, there is an issue of Doppler-angle ambiguity due to the properties of the modulation scheme. In other words, the maximum detectable velocity is reduced in proportion to the number of Tx antennas, and the angle estimation performance can be degraded when a moving target induces a Doppler phase shift. Therefore, in this paper, we propose a method for solving the Doppler-angle ambiguity in the BPSK-MIMO FMCW radar system. The proposed method involves comparing and arranging the phases of signals corresponding to the same target in the range-velocity detection results. By arranging the phases to form an arithmetic sequence, the signals from each Tx antenna can be distinguished and the unambiguous velocity and angle of the target can be estimated. In addition, by using a general phase-shift keying (PSK) modulation scheme, the proposed method can be applied to an arbitrary MIMO system regardless of the number of Tx antennas.INDEX TERMS Doppler-angle ambiguity, binary phase-shift keying (BPSK), frequency-modulated continuous-wave (FMCW), multiple-input multiple-output (MIMO)

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Concept and Implementation of a PLL-Controlled Interlaced Chirp Sequence Radar for Optimized Range–Doppler Measurements

Cited by 23 publications

References 18 publications

Complex-Valued Channel Attention and Application in Ego-Velocity Estimation With Automotive Radar

Complex-Valued Channel Attention and Application in Ego-Velocity Estimation With Automotive Radar

Radar Sensors for Autonomous Driving: Modulation Schemes and Interference Mitigation

Solving Doppler-Angle Ambiguity of BPSK-MIMO FMCW Radar System

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