An Efficient Frequency and Phase Estimation Algorithm With CRB Performance for FMCW Radar Applications

Scherr, Steffen; Ayhan, Serdal; Fischbach, Benjamin; Bhutani, Akanksha; Pauli, Mario; Zwick, Thomas

doi:10.1109/tim.2014.2381354

Cited by 89 publications

(42 citation statements)

References 12 publications

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“…To determine the statistically most accurate measurement method given the signal model (1) the CRLB for TOF estimation is reviewed, once based on frequency f and once based on the phase component φ [18,19,20]. Combining (2) and (4) yields the CRLB varτ^df≥122π2·SNR·B2·N based on frequency, while inserting (5) into (3) gives the phase-based CRLB as varτ^dφ≥42π2·SNR·f02·N0.222222em.…”

Section: Materials and Methodsmentioning

confidence: 99%

Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers

Och

Schrattenecker²,

Schuster

et al. 2019

Sensors

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A primary concern in a multitude of industrial processes is the precise monitoring of gaseous substances to ensure proper operating conditions. However, many traditional technologies are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative but suffer from high cost and limited accuracy in highly cluttered industrial plants. This paper examines the performance limits of low-cost frequency-modulated continuous-wave (FMCW) radar sensors for permittivity measurements. First, the accuracy limits are investigated theoretically and the Cramér-Rao lower bounds for time-of-flight based permittivity and concentration measurements are derived. In addition, Monte-Carlo simulations are carried out to validate the analytical solutions. The capabilities of the measurement concept are then demonstrated with different binary gas mixtures of Helium and Carbon Dioxide in air. A low-cost time-of-flight sensor based on two synchronized fully-integrated millimeter-wave (MMW) radar transceivers is developed and evaluated. A method to compensate systematic deviations caused by the measurement setup is proposed and implemented. The theoretical discussion underlines the necessity of exploiting the information contained in the signal phase to achieve the desired accuracy. Results of various permittivity and gas concentration measurements are in good accordance to reference sensors and measurements with a commercial vector network analyzer (VNA). In conclusion, the proposed radar-based low-cost sensor solution shows promising performance for the intended use in demanding industrial applications.

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Section: Materials and Methodsmentioning

confidence: 99%

Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers

Och

Schrattenecker²,

Schuster

et al. 2019

Sensors

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show abstract

“…Due to the limitation of the measurement interval, which equals the duration of the modulation, the frequency spectrum of a single reflector corresponds to a sinc function with center frequency fb. The distance between the object and the transceiver linearly depends on fb, and can be accurately evaluated [21,26]. However, for thickness determination, the width of one main lobe restricts the ability to distinguish it from a second reflection peak and therefore limits the resolution.…”

Section: Fmcw Thickness Measurementsmentioning

confidence: 99%

Multilayer Thickness Measurements below the Rayleigh Limit Using FMCW Millimeter and Terahertz Waves

Schreiner

Sauer-Greff

Urbansky

et al. 2019

Sensors

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We present thickness measurements with millimeter and terahertz waves using frequency-modulated continuous-wave (FMCW) sensors. In contrast to terahertz time-domain spectroscopy (TDS), our FMCW systems provide a higher penetration depth and measurement rates of several kilohertz at frequency modulation bandwidths of up to 175 GHz. In order to resolve thicknesses below the Rayleigh resolution limit given by the modulation bandwidth, we employed a model-based signal processing technique. Within this contribution, we analyzed the influence of multiple reflections adapting a modified transfer matrix method. Based on a brute force optimization, we processed the models and compared them with the measured signal in parallel on a graphics processing unit, which allows fast calculations in less than 1 s. TDS measurements were used for the validation of our results on industrial samples. Finally, we present results obtained with reduced frequency modulation bandwidths, opening the window to future miniaturization based on monolithic microwave integrated circuit (MMIC) radar units.

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“…For N=2048 samples and SNR of 10 the standard error of range has a lower bound of 2.7 m. In [16] it is shown that in practice the standard error can be 6 or 7 times larger due to system imperfections. In any case even with a limited SNR of 10 the range error can be of the order of 30 m, which is one order of magnitude below the displacements that need to be measured.…”

Section: Reflector Design and Constructionmentioning

confidence: 99%

Collimated Beam FMCW Radar for Vital Sign Patient Monitoring

Prat

Blanch

Aguasca

et al. 2019

IEEE Trans. Antennas Propagat.

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Patient monitoring of vital signals such as breathing rhythm and heart beat rate can be done remotely by the use of a radar system. This approach is advantageous since it does not require any contact with the patient. Obviously contactless monitoring results in a more comfortable situation for the patient, and in occasions it is almost mandatory as in the case of heavy burnt or newborn patients. Moreover, additional information such movement patterns are also available. A 120 GHz FMCW radar is described with special focus on the design, construction and testing of a specific reflector antenna for the system. The system is based on a commercial radar chipset that includes its own antennas. The challenge has been to design the optimum reflector and to build it and test it in a cost effective way. The reflector has been 3D printed and a near-field testing technique has been implemented to assess its performance. The results show that the system is able to measure the vital signs at distances beyond one meter.

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An Efficient Frequency and Phase Estimation Algorithm With CRB Performance for FMCW Radar Applications

Cited by 89 publications

References 12 publications

Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers

Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers

Multilayer Thickness Measurements below the Rayleigh Limit Using FMCW Millimeter and Terahertz Waves

Collimated Beam FMCW Radar for Vital Sign Patient Monitoring

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