Analysis Of Snow Water Equivalent (Swe) Of Snowpack By An Ultra Wide Band Step Frequency Continuous Wave Radar (Sfcw)

Snow makes a great contribution to the hydrological cycle in cold regions. The parameter to characterize available the water from the snow cover is the well-known snow water equivalent (SWE). This paper presents a near-surface-based radar for determining the SWE from the measured complex spectral reflectance of the snowpack. The method is based in a stepped-frequency continuous wave radar (SFCW), implemented in a coherent software defined radio (SDR), in the range from 150 MHz to 6 GHz. An electromagnetic model to solve the electromagnetic reflectance of a snowpack, including the frequency and wetness dependence of the complex relative dielectric permittivity of snow layers, is shown. Using the previous model, an approximated method to calculate the SWE is proposed. The results are presented and compared with those provided by a cosmic-ray neutron SWE gauge over the 2019–2020 winter in the experimental AEMet Formigal-Sarrios test site. This experimental field is located in the Spanish Pyrenees at an elevation of 1800 m a.s.l. The results suggest the viability of the approximate method. Finally, the feasibility of an auxiliary snow height measurement sensor based on a 120 GHz frequency modulated continuous wave (FMCW) radar sensor, is shown.

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A Doppler Range Compensation for Step-Frequency Continuous-Wave Radar for Detecting Small UAV

Sensors ◽

10.3390/s19061331 ◽

2019 ◽

Vol 19 (6) ◽

pp. 1331

Author(s):

Massimiliano Pieraccini ◽

Lapo Miccinesi ◽

Neda Rojhani

Keyword(s):

Short Range ◽

Continuous Wave ◽

Range Shift ◽

Specific Method ◽

Step Frequency ◽

Wave Radar ◽

Small Uav ◽

The Doppler Effect ◽

Set Up ◽

Free Falling

Step-frequency continuous-wave (SFCW) modulation can have a role in the detection of small unmanned aerial vehicles (UAV) at short range (less than 1–2 km). In this paper, the theory of SFCW range detection is reviewed, and a specific method for correcting the possible range shift due to the Doppler effect is devised. The proposed method was tested in a controlled experimental set-up, where a free-falling target (i.e., a corner reflector) was correctly detected by an SFCW radar. This method was finally applied in field for short-range detection of a small UAV.

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Step frequency continuous wave RADAR sensor for level measurement of molten solids

Journal of Electromagnetic Waves and Applications ◽

10.1080/09205071.2017.1380540 ◽

2017 ◽

Vol 32 (3) ◽

pp. 281-292 ◽

Cited By ~ 4

Author(s):

Yugandhara R. Yadam ◽

Balamurugan T. Sivaprakasam ◽

Krishnamurthy C. Venkata ◽

Kavitha Arunachalam

Keyword(s):

Continuous Wave ◽

Step Frequency ◽

Radar Sensor ◽

Level Measurement ◽

Wave Radar

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Brachialis Pulse Wave Measurements with Ultra-Wide Band and Continuous Wave Radar, Photoplethysmography and Ultrasonic Doppler Sensors

Sensors ◽

10.3390/s21010165 ◽

2020 ◽

Vol 21 (1) ◽

pp. 165

Author(s):

Horst Hellbrück ◽

Gunther Ardelt ◽

Philipp Wegerich ◽

Hartmut Gehring

Keyword(s):

Blood Pressure ◽

Pulse Wave ◽

Continuous Wave ◽

Cuff Pressure ◽

Wide Band ◽

Pulse Radar ◽

Wave Measurements ◽

Wave Radar ◽

Complete Measurement ◽

Cw Radar

The measurement and analysis of the arterial pulse wave provides information about the state of vascular health. When measuring blood pressure according to Riva-Rocci, the systolic and diastolic blood pressure is measured non-invasively with an inflatable pressure cuff on the upper arm. Today’s blood pressure monitors analyze the pulse wave in reference to the rising or falling cuff pressure. With the help of additional pulse wave analysis, one can determine the pulse rate and the heart rate variability. In this paper, we investigated the concept, the construction, and the limitations of ultrawideband (UWB) radar and continuous wave (CW) radar, which provide continuous and non-invasive pulse wave measurements. We integrated the sensors into a complete measurement system. We measured the pulse wave of the cuff pressure, the radar sensor (both UWB and CW), the optical sensor, and ultrasonic Doppler as a reference. We discussed the results and the sensor characteristics. The main conclusion was that the resolution of the pulse radar was too low, even with a maximum bandwidth of 10 GHz, to measure pulse waves reliably. The continuous wave radar provides promising results for a phantom if adjusted properly with phase shifts and frequency. In the future, we intend to develop a CW radar solution with frequency adaption.

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Review article: Performance assessment of electromagnetic wave-based field sensors for SWE monitoring

10.5194/tc-2021-163 ◽

2021 ◽

Author(s):

Alain Royer ◽

Alexandre Roy ◽

Sylvain Jutras ◽

Alexandre Langlois

Keyword(s):

Electromagnetic Waves ◽

Gamma Ray ◽

Continuous Wave ◽

Snow Water Equivalent ◽

Low Cost ◽

Cosmic Ray ◽

Satellite System ◽

Fmcw Radar ◽

Wave Radar ◽

Global Navigation Satellite

Abstract. Continuous and spatially distributed data of snow mass (snow water equivalent, SWE) from automatic ground-based measurements are increasingly required for climate change studies and for hydrological applications (snow hydrological model improvement and data assimilation). We present and compare four new-generation non-invasive sensors that are based on electromagnetic waves for direct measurements of SWE: Cosmic Ray Neutron Probe (CNRP); Gamma Ray Monitoring (GMON) scintillator; frequency-modulated continuous-wave radar (FMCW-Radar) at 24 GHz; and Global Navigation Satellite System (GNSS) receivers for SWE retrieval. All four techniques are relatively low cost, have low power requirements, provide continuous and autonomous measurements, and can be installed in remote areas. Their operating principles are briefly summarized before examples of comparative measurements are provided. A performance review comparing their advantages, drawbacks and accuracies is discussed. Overall instrument accuracy is estimated to range between 9 and 15 %.

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Measurement of Snow Water Equivalent Using Drone-Mounted Ultra-Wide-Band Radar

Remote Sensing ◽

10.3390/rs13132610 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2610

Author(s):

Rolf Ole R. Jenssen ◽

Svein K. Jacobsen

Keyword(s):

Field Experiments ◽

Snow Water Equivalent ◽

Wide Band ◽

Density Estimator ◽

Snow Density ◽

Initial Field ◽

Density Estimates ◽

Snow Water ◽

Pseudo Noise ◽

Further Development

The use of uav-mounted radar for obtaining snowpack parameters has seen considerable advances over recent years. However, a robust method of snow density estimation still needs further development. The objective of this work is to develop a method to reliably and remotely estimate swe using uav-mounted radar and to perform initial field experiments. In this paper, we present an improved scheme for measuring swe using uwb (0.7GHz–4.5GHz) pseudo-noise radar on a moving uav, which is based on airborne snow depth and density measurements from the same platform. The scheme involves autofocusing procedures with the f-k migration algorithm combined with the Dix equation for layered media in addition to altitude correction of the flying platform. Initial results from field experiments show high repeatability (R>0.92) for depth measurements up to 5.5 m, and good agreement with Monte Carlo simulations for the statistical spread of snow density estimates with standard deviation of 0.108 g/cm3. This paper also outlines needed system improvements to increase the accuracy of a snow density estimator based on an f-k migration technique.

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