ALOS-2 / Calibration Result of JAXA standard products
(ver. 2014.11.20, Initial calibration results)

(As of Nov. 20, 2014)

JAXA has conducted the calibration and validation of the PALSAR-2 and its standard products within the PALSAR-2 initial calibration phase (i.e., from Aug. 4, 2014 to Nov. 20, 2014), and we confirmed 1) that PALSAR-2 products have shown the very good radiometric and the geometric performances as requested from the product specification and as shown in the Table 1, and 2) PALSAR-2 has had good enough performance for monitoring the earth environment and the disaster status. While JAXA will start the data distribution officially on Nov. 25, 2014 as a result of the calibration review, we will continue the calibration and validation of the PALSAR-2 and its standard products for maintaining and further improvement of the PALSAR-2 image performances. Here, we will describe the calibration results of the PALSAR-2 in Table 1 and method to convert the PALSAR-2 data to radar backscatter of the target.

Table 1 Initial Calibration (Summary, 2014/11/20)
Note: results are from the JAXA Calval.
Items Results Data Requirement
Geometry
(RMSE)
High resolution/
Spotlight mode		 5.34m (L1.1)/6.73m (L2.1)
127/129 20m
ScanSAR mode 60.77m (L1.1)/29.93m (L2.1)
7/8 100m
Radiometry
Corner reflector 1.31 (CF: -81.60)
Amazon (forest) 0.406 (CF: -82.34)
NESZ (F/H/U) HH -41.1 (F)/-36.0 (H)/-36.6 (U)
HV -49.2 (F)/-46.0(H)
120
30 scenes
 
 
1.0 dB
1.0 dB: -6.84dB@Amazon
-26.0 (F)/-28.0 (H)/-24.0 (U)
 
Polarimetry
VV / HH 1.0143 (σ: 0.06)
VV /HH phase (deg.) 0.350 (σ: 0.286)
Cross talk (dB) -43.7 (σ: 6.65) hv/hh
-44.0 (σ: 7.10) vh/vv
-48.2 (σ: 6.05) corr
6
 
 
 
 
1.047
5 deg.
-30 dB
-30 dB
-30 dB
Resolution (m)
Azimuth/Range
Spotlight 0.79 (σ: 0.028)/1.66 (σ: 0.04)
High resolution [3m] 2.81 (σ: 0.034)/1.70 (σ: 0.022)
High resolution [6m] 4.06 (σ: 0.108)/3.53 (σ: 0.317)
High resolution [10m] 5.05 (σ: 0.110)/5.36 (σ: 0.126)
3
35
28
61
1.00×1.1/1.78
2.75×1.1/1.78
3.75×1.1/3.57
5.00×1.1/5.36
Sidelobes
PSLR (Azimuth) -16.20 (σ: 2.53)
PSLR (Range) -12.59 (σ: 1.84)
ISLR -8.80 (σ: 3.23)
124
 
 
-13.26dB+2dB
-13.26dB+2dB
-10.16dB+2dB
Anbiguity
Azimuth 23~14 (mean: 20)
Range Invisible
7 scenes
 
More than 20~25dB
More than 25dB
    Note)
  • PSLR: Peak to Sidelobe Ratio, ISLR: Integrated Sidelobe Ratio.
    U is High resolution [3m]、H for [6m]、F for [10m].
    Standard dev. of CF is 1.31 will be tuned under 1.0 synchronized with Amazon calibration data.

Conversion from digital number (DN) to the backscattering coefficient (sigma-naught) (dB) can be done by the following equations.

  • Conversion from digital number (DN) to the backscattering coefficient (sigma-naught) (dB) can be done by the following equations. (1)
  • (for L1.5, 2.1)
  • Conversion from digital number (DN) to the backscattering coefficient (sigma-naught) (dB) can be done by the following equations. (2)
  • (for L1.1)
CF mean (dB) std (dB)
CF1 -83.0 0.406
A 32.0 -
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