Signatures of Forest Radar Images at VHF-band

1
Signatures of Forest Radar Images atVHF-band
2
Overview

• Airborne SAR system IMARK
• Simultaneous radar and ground-based forest
  measurements
• GPR sensing
• Dependencies of backscattered signal on forest
  parameters
• Conclusions

3
Airborne SAR Complex IMARK
4
Disposition of the Antennas on the Plane
5
Main Features of the IMARK SAR Complex
Parameter Value Value Value Value
Frequency X L P VHF
Wavelength, cm 3.9 23 68 254
Polarization VV, HH, VH, HV VV, HH, VH, HV VV, HH, VH, HV VV, HH, VH, HV
Resolution, m 4-6 8-10 10-15 15-20
Antennas gain, dB 30 14-17 14-17 9-11
Width in azimuth, deg 18 24 24 40
Width in elevation, deg 24 24 24 60
6
Images Obtained by SAR System IMARK
L-band
P-band
VHF-band
Spas-Klepiki, Ryazanskaya Region
7
The process of boring for the sampling of soil
and the appearance of soil samples taken from
different depths
8
(No Transcript)
9

Use of GPR for carrying out investigations on
permittivity fluctuations in subsurface soil
layers
10
The examples of GPR measurements in particular
points
11
Theoretical estimation of backscattering from
forest stand
Typical scattering mechanisms
Scattering from array of cylinders with height
distribution
12
Scattering from layered medium with spatially
inhomogeneous dielectric permittivity
Three layers layers 1, 2 are inhomogeneous,
layer 3 is homogeneous. Correlation function of
dielectric permittivity
Case 2 Layer 2 with large inhomogeneities (root
system)
Case 1 Layer 2 without large inhomogeneities
13
Experimental dependencies of backscattered signal
on stem diameter and distance between trees
14
Experimental dependencies of backscattered signal
on tree height and biomass
15
Conclusions

• Backscatter from forest at VHF band at HH
  polarization increases with the growth of biomass
  and tree diameter
• Measurements conducted by ground penetrating
  radar confirm spatial variation of dielectric
  constant of the upper subsurface soil layer of
  forest
• Large fluctuations of dielectric permittivity of
  the upper soil layer related with the presence of
  tree root system have significant importance in
  the formation of backscatter from forestland
• Measurements conducted in different periods of
  time indicate the seasonal variation of
  backscatter from coniferous forest