Coherent Measurements With MIMO Radar Networks of Incoherent FMCW Sensor Nodes

Frischen, Andreas; Hakobyan, Gor; Waldschmidt, Christian

doi:10.1109/lmwc.2020.2998081

Cited by 16 publications

(11 citation statements)

References 16 publications

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“…Many of those concepts built up on the two sensor networks are published in [95]. A concepts for N FMCW-sensors was presented in [96] with coherent processing in [97]. Alternative concepts comprise the integration of radar repeaters into the networks [98].…”

Section: Radar Networkmentioning

confidence: 99%

Automotive Radar — From First Efforts to Future Systems

2021

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Section: Radar Networkmentioning

confidence: 99%

Automotive Radar — From First Efforts to Future Systems

2021

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“…On the other hand, there are the paths s k,l , k = l with the reflections on different targets on the way to the repeater and back, named multitarget paths. Thus, analogous to (12), the bistatic signals are based on a linear combination of all the targets. However, since the paths s k,l and s l,k are resulting in the same range and the same relative velocity, only…”

Section: Interpretation Of the Bistatic Radar Imagementioning

confidence: 99%

“…Furthermore, the phase noise still remains uncorrelated and reduces the performance. In [12], coherency is retrieved without a synchronization signal but with a joint digital signal processing. However, this requires a digital baseband link between the radar nodes and also suffers from uncorrelated phase noise.…”

Section: Introductionmentioning

confidence: 99%

OFDM-Based Radar Network Providing Phase Coherent DOA Estimation

Werbunat¹,

Meinecke²,

Schweizer³

et al. 2021

IEEE Trans. Microwave Theory Techn.

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Next-generation radar sensors require imaging capabilities with high angular resolution. As for a single sensor, the aperture, and thus the achievable resolution, is limited due to the constraints of the front end, radar networks consisting of multiple sensors are a possible solution. However, their incoherency usually makes joint angle estimation impossible. This article presents a network concept consisting of an orthogonal frequency-division multiplexing (OFDM) radar and repeater elements, which receive the reflections from targets and retransmit them back to the radar. Thereby, any frequency conversion from radio frequency to baseband and vice versa is omitted such that the signal remains coherent to the initial transmit signal. To distinguish the bistatic signal transmitted by the repeater from the monostatic one of the OFDM radar, the orthogonal subcarrier structure of OFDM waveforms is exploited by combining a sparse radar transmit signal with a low-frequency modulation in the repeater. This allows to evaluate the bistatic signals at the radar with standard multiple-input-multiple-output (MIMO)-OFDM signal processing, leading to separate range-Doppler images for each virtual channel. Finally, it is shown that this method offers a coherent angular estimation based on the extended aperture of the network. For this purpose, a method to establish phase coherency by a reconstruction of the modulation phase is presented. The network concept is proved with measurements at 77 GHz.

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“…It allows bistatic or multistatic measurements and derives unknown synchronization parameters from the ADC samples. PN compensation and precise velocity measurements are enabled for localization applications or the detection of passive targets [47].…”

Section: Classification Of Distributed Radar Systemsmentioning

confidence: 99%