KOMPSAT-5 Image Quality Measurement in 2017

Transcription

1 Korea Aerospace Research Institute Program Office Gwahangno Yuseong-gu Daejeon, , Korea Image Quality Measurement in Nov 2017 Korea Aerospace Research Institute Horyung Jeong, Donghyun Kim, Dochul Yang, and Donghan Lee K5 CAL/VAL Team

2 K5 Image Quality for Extended Mode K5 System Image Quality for Extended Mode Extended Mode (Newly Added) CALVAL 2

3 Mongolia CAL Site Construction Constructed Mongolia CAL Sites Stable ground places No manmade structures (fences, antenna, buildings, etc.) But, considering the protection of CR No riverside Gentle slope area Meadows & bare soils HR-Mode CR ST-Mode CR CALVAL CAL Site in Mongolia 3

4 Clutter Analysis via TerraSAR-X Images Clutter Analysis from TerraSAR-X Images Measured Monglia site clutter level via the TerraSAR-X Images Clutter Level except ST-07D Area(09/Sep/2010) : about -18 [dbsm] Clutter Level except ST-07D Area(20/Sep/2010) : about -19 [dbsm] All clutter level of calibration site have smaller than -10dBsm, designed clutter value to have more than 30dB Signal-to-Clutter Ratio Background Level of ST-CR Background Level of ST-CR MEAN of Background Level [09-09] MEAN of Background Level [09-20] Background Level [db] D 04A 05D 06A 07D 08A 12D 12D_N 14D 15A 19D ST-CR CALVAL 4

5 Procedure to install CR in the CAL Site Procedure to install CR in the Calibration Site 1 3 CR installation 1 [MTG] 2 [KASI] 3 [MTG] Installation of CR Tripod on Concrete base Installation of pedestal & Reflector Installation of GPS Measurement Device Measurement of True-North & East/West Direction using GPS Measurement Result CR True-North Alignment Azimuth & Elevation Alignment 2 CALVAL 5

6 CR Installation in Mongolia Site Final CR Deployment for Mongolia Site 52 CRs consisting of 32 HR and 20 ST CRs were installed in the Site Requirement 1 Frequency 9660MHz(±1200MHz) Measurement / Analysis Result 9660MHz(±1200 MHz) 2 RCS ST CR +45 db m2 (±1dB) dbsm HR CR +35 db m2 (±1dB) dbsm 3 RCS Stability 0.1 db 0.1 db 4 Pointing Elevation 35 ~ ~ 70 Azimuth Residual Motion 0.5 mm 0.5 mm 6 Size ST CR 1.72x1.72 m2 (surface) 1.72x1.72 m2 (surface) HR CR 1 x 1 m2 (surface) 1 x 1 m2 (surface) 7 Wind Stability 200km/h 200km/h 8 Load Test ST CR 3mm ( 1000kg) < 2mm ( 1000kg) HR CR 10mm ( 330kg) < 4mm ( 330kg) 9 Temperature Range -40 / /+50 CALVAL 6

7 K5 Mongolia CAL Site : CR Image Example of K5 ST & HR CR Images ST Image includes many CRs because of its 30km coverage In case of HR image, usually one or two CRs are included in the image because of its 5km coverage Example of HR CR Image Example of ST CR Image CALVAL 7

8 Radiometric Accuracy (1/3) Radiometric Accuracy - EH Mode Mean offset values of radiometric error measured from 3 EH mode during 9 s are lower than 0.2dB, and STD of radiometric error is about 0.2dB In cases of February and August, radiometric accuracy of some EH mode were not measured because of Mongolia s bad weather conditions, such as heavy snow and rain, respectively EH Mode Radiometric Error EH-04 EH-10 EH-16 CR ID Mean STD radiometric error [dbsm] EH EH EH CALVAL 8

9 Radiometric Accuracy (2/3) Radiometric Accuracy - UH Mode Mean offset values of radiometric error measured from 3 EH mode during 9 s are lower than 0.2dB, and STD of radiometric error is about 0.2dB In some cases, radiometric accuracy was not measured because of Mongolia s bad weather condition, such as heavy snow and rain UH Mode Radiometric Error UH-24 UH-25 UH-30 CR ID Mean STD radiometric error [dbsm] UH UH UH CALVAL 9

10 Radiometric Accuracy (3/3) Radiometric Accuracy - ES Mode Mean offset values of radiometric error measured from 3 ES mode during 9 s are about 0.3dB, and STD of radiometric error is about 0.3dB Mean offset and STD of ES mode is slight larger than EH and UH, because ES coverage is wider than EH/UH and many ES beam can access one ST CR. In some cases, radiometric accuracy was not measured because of Mongolia s bad weather condition, such as heavy snow and rain ES Mode Radiometric Error ES-06 ES-08 ES-18 radiometric error [dbsm] CR ID Mean STD ES ES ES CALVAL 10

11 Geo-Location Accuracy K5 Geo-Location Accuracy Two kind of orbit data of which accuracy are 10 m accuracy (ORBNAV) and 1 m accuracy (POES) were applied to the same image data Image data acquired during July was used to measure geo-location accuracy Geo-Location Accuracy increased from to m CE90 error 3 CE90 Error = m 2 CE90 Error = m error [m] 0-1 error [m] error [m] Geo-Location Error with ORBNAV ST DESC HR DESC ST ASC HR ASC ST DESC HR DESC ST ASC HR ASC error [m] Geo-Location Error with POED CALVAL 11

12 Resolution Measurement (1/3) EH Mode Resolution Number of EH beam is 31, and beams from EH-17 to 31 have 1 m requirement Measured EH resolution is stable and comply with the requirement Sometime measurement slightly increases because of weather condition EH-16 Beam Resolution CALVAL EH-08 Beam Resolution EH-10 Beam Resolution 0.9 EH-19 Beam Resolution Beam ID Range [m] Azimuth [m] Design Max. Design Max. EH EH EH EH

13 Resolution Measurement (2/3) UH Mode Resolution Number of UH beam is 9, and beams from UH-27 to 31 have 0.85 m requirement Measured UH resolution is comply with the requirement Sometime measurement fails because of bad weather condition such as heavy rain UH-27 Beam Resolution UH-30 Beam Resolution UH-28 Beam Resolution 0.83 UH-31 Beam Resolution Beam ID Range [m] Azimuth [m] Design Max. Design Max. UH UH UH UH CALVAL

14 Resolution Measurement (3/3) ES Mode Resolution Number of ES beam is 19, and beams from ES-05 to 19 have 2.5 m requirement ES resolution measurement sample is relatively larger than that of EH and UH, because ES image contains many CR responses due to its 30km coverage Measured ES resolution is comply with the requirement ES-15 Beam Resolution ES-06 Beam Resolution ES-10 Beam Resolution 2.3 ES-18 Beam Resolution Beam ID Range [m] Azimuth [m] Design Max. Design Max. ES ES ES ES CALVAL

15 ISLR & PSLR Measurement (1/2) ISLR & PSLR Measurement During July 2017 K5 requirement of ISLR and PSLR are -13dB and -17dB, respectively. Most ISLR & PSLR measurements comply with the requirement well However, some measurement is not comply with the requirement, because of heavy rain on some part of image 5 0 Jul 2017 ISLR measurement (Mongolia) K5 Requirement = -13dB 5 0 Jul 2017 PSLR measurement (Mongolia) -5 ISLR [db] PSLR [db] K5 Requirement = -17dB date date CALVAL 15

16 ISLR & PSLR Measurement (2/2) Measurement Example bad weather condition day In case of ES mode acquisition, 4 CRs were included in the image Measurement from three CRs are comply with the requirement, but one CR didn t comply It means that root cause of not-compliance is not due to satellite, but bad weather condition of ST15A CR If the root cause was due to satellite, all measurement have to not comply with the requirements Sensing Start Time Mode Beam ID :35: :35: :35: :35:10 Looking Orbit Type CR ID ISLR_R [db] ISLR_Az [db] PSLR_R [db] PSLR_Az [db] ES ES-15 R A ST04A ES ES-15 R A ST06A ES ES-15 R A ST08A ES ES-15 R A ST15A CALVAL 16

17 Conclusion Mongolia Calibration Site is sufficiently suitable site for SAR calibration because of very low backscattering coefficient K5 image quality measurement shows that K5 maintains its performance Radiometric error is about 0.3 db mean and 0.3 db STD Geo-location error can be enhanced from to by applying more accurate orbit data (POED) Resolution, PSLR and ISLR measurement comply with the requirement Some not-compliance measurement is due to bad weather condition of CR, not satellite issue CALVAL 17

18 CDR, 5/20-5/23/08 [Calibration and Validation] K5-CDR-4D-18