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Time-Domain Simulation of Along-Track Interferometric SAR for Moving Ocean Surfaces.

Yoshida T, Rheem CK - Sensors (Basel) (2015)

Bottom Line: As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces.The phase differences shifted by currents were in good agreement with the theoretical values.Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed.

View Article: PubMed Central - PubMed

Affiliation: Department of Ocean Technology, Policy and Environment, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 153-8505, Japan. tyoshida@iis.u-tokyo.ac.jp.

ABSTRACT
A time-domain simulation of along-track interferometric synthetic aperture radar (AT-InSAR) has been developed to support ocean observations. The simulation is in the time domain and based on Bragg scattering to be applicable for moving ocean surfaces. The time-domain simulation is suitable for examining velocities of moving objects. The simulation obtains the time series of microwave backscattering as raw signals for movements of ocean surfaces. In terms of realizing Bragg scattering, the computational grid elements for generating the numerical ocean surface are set to be smaller than the wavelength of the Bragg resonant wave. In this paper, the simulation was conducted for a Bragg resonant wave and irregular waves with currents. As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces. The phase differences shifted by currents were in good agreement with the theoretical values. Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed.

No MeSH data available.


Related in: MedlinePlus

Simulation results of irregular waves for wind speed 7.5 m/s. (a) Phase of simulated SAR signals of master and slave antennas in the azimuth direction; (b) Phase differences of (a). The black line shows the phase differences. The red line shows the average.
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sensors-15-13644-f009: Simulation results of irregular waves for wind speed 7.5 m/s. (a) Phase of simulated SAR signals of master and slave antennas in the azimuth direction; (b) Phase differences of (a). The black line shows the phase differences. The red line shows the average.

Mentions: The results of the simulated SAR signals in the azimuth direction for three wind speeds are shown in Figure 7a, Figure 8a, Figure 9a, Figure 10a, Figure 11a and Figure 12a, that are SAR signals of master and slave antennas. The phase differences between two antennas are displayed in Figure 7b, Figure 8b, Figure 9b, Figure 10b, Figure 11b and Figure 12b. The results represent the phase differences for uniform surface current, phase velocity of the Bragg resonant wave, and orbital motions of irregular waves. The wind surface velocity is neglected in the numerical surfaces of this simulation. The fluctuations seen in these figures are due to irregular backscattering microwave effects, in other words, microwave backscattering randomly occurs on irregular wave surfaces. It can be treated as speckle noise.


Time-Domain Simulation of Along-Track Interferometric SAR for Moving Ocean Surfaces.

Yoshida T, Rheem CK - Sensors (Basel) (2015)

Simulation results of irregular waves for wind speed 7.5 m/s. (a) Phase of simulated SAR signals of master and slave antennas in the azimuth direction; (b) Phase differences of (a). The black line shows the phase differences. The red line shows the average.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507666&req=5

sensors-15-13644-f009: Simulation results of irregular waves for wind speed 7.5 m/s. (a) Phase of simulated SAR signals of master and slave antennas in the azimuth direction; (b) Phase differences of (a). The black line shows the phase differences. The red line shows the average.
Mentions: The results of the simulated SAR signals in the azimuth direction for three wind speeds are shown in Figure 7a, Figure 8a, Figure 9a, Figure 10a, Figure 11a and Figure 12a, that are SAR signals of master and slave antennas. The phase differences between two antennas are displayed in Figure 7b, Figure 8b, Figure 9b, Figure 10b, Figure 11b and Figure 12b. The results represent the phase differences for uniform surface current, phase velocity of the Bragg resonant wave, and orbital motions of irregular waves. The wind surface velocity is neglected in the numerical surfaces of this simulation. The fluctuations seen in these figures are due to irregular backscattering microwave effects, in other words, microwave backscattering randomly occurs on irregular wave surfaces. It can be treated as speckle noise.

Bottom Line: As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces.The phase differences shifted by currents were in good agreement with the theoretical values.Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed.

View Article: PubMed Central - PubMed

Affiliation: Department of Ocean Technology, Policy and Environment, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 153-8505, Japan. tyoshida@iis.u-tokyo.ac.jp.

ABSTRACT
A time-domain simulation of along-track interferometric synthetic aperture radar (AT-InSAR) has been developed to support ocean observations. The simulation is in the time domain and based on Bragg scattering to be applicable for moving ocean surfaces. The time-domain simulation is suitable for examining velocities of moving objects. The simulation obtains the time series of microwave backscattering as raw signals for movements of ocean surfaces. In terms of realizing Bragg scattering, the computational grid elements for generating the numerical ocean surface are set to be smaller than the wavelength of the Bragg resonant wave. In this paper, the simulation was conducted for a Bragg resonant wave and irregular waves with currents. As a result, the phases of the received signals from two antennas differ due to the movement of the numerical ocean surfaces. The phase differences shifted by currents were in good agreement with the theoretical values. Therefore, the adaptability of the simulation to observe velocities of ocean surfaces with AT-InSAR was confirmed.

No MeSH data available.


Related in: MedlinePlus