systematic product analysis l.
Download
Skip this Video
Download Presentation
Systematic Product Analysis

Loading in 2 Seconds...

play fullscreen
1 / 32

Systematic Product Analysis - PowerPoint PPT Presentation


  • 117 Views
  • Uploaded on

Systematic Product Analysis. Christopher Buck ENVISAT Programme ESA/ESTEC. Purpose. ASAR generates typically ~100 products per day Each contains vital information on the health of the instrument, level settings, processing problems etc

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Systematic Product Analysis' - constantine


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
systematic product analysis

Systematic Product Analysis

Christopher Buck

ENVISAT Programme

ESA/ESTEC

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

purpose
Purpose
  • ASAR generates typically ~100 products per day
  • Each contains vital information on the health of the instrument, level settings, processing problems etc
  • Systematic product analysis is required to monitor the instrument and product status, providing inputs to the instrument and processor operation and flagging any problems in a timely fashion

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

product types ingested for analysis
Product Types Ingested for Analysis
  • Module Stepping Mode: ASA_MS__0*
  • Image Mode Medium Resolution ASA_IMM_1*
  • Wave Spectra ASA_WVS_1*
  • Wave Image ASA_WVI_1*
  • Global Monitoring ASA_GM1_1*
  • Alternating Polarization Medium Resolution ASA_APM_1*

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

module stepping mode analysis
Module Stepping Mode Analysis
  • Source packet chirps read in
  • Compressed with ideal chirp
  • Gain and phase of each module determined
  • Transmit and Receive
  • Horizontal and Vertical Polarization
  • Time stamped
  • Entered into Database

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

module stepping mode database

320

Module Stepping Mode Database

A1-E4

H or V

1-16

ASA_MS__0*.N1

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

module stepping mode analysis6
Module Stepping Mode Analysis
  • Provides:
    • Instant health check of all modules tx/rx, H/V, Gain/Phase
    • History of tx/rx, Gain/Phase for each module and each polarization
    • Phase and amplitude errors as input into antenna pattern analysis

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

module stepping mode health check
Module Stepping Mode Health Check

< 1 LSB error

> 1 LSB error

> 2 LSB error

> 3 LSB error

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

pattern and gain calibration
Pattern and Gain Calibration

Antenna Gain

Test Results

Transponder

Beam

Antenna

Gain

External

Characterisation

Embedded Row

Test Results

Internal

Calibration

Beam Coefficients

Module

Stepping

Antenna B/F

Near-field data

Beam

Radiation

Pattern

Rain Forest

Doppler Spectrum

Antenna B/F

Test Results

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

module stepping mode history
Module Stepping Mode History
  • Long-term comparison against pre-launch reference data set shows trends in module behaviour

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

antenna stability tx
Antenna Stability - Tx

 = 0.25dB

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

antenna stability rx
Antenna Stability - Rx

 = 0.4dB

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

internal calibration

P3

P2

Tx Aux

P1A

P1

P1

P1

Cal BFN

Cal

Rx Aux

Internal Calibration
  • ASAR is equipped with
  • an automatic temperature
  • compensation scheme to
  • compensate for phase/gain
  • drifts at T/R module level
  • Direct monitoring of any
  • residual gain drifts for
  • later correction
  • Continuous measurements
  • even during data acquisition

T/R Module

(1 of 32x10)

Radiating

Row

Signal BFN

Tx Main

Rx Main

  • Use of special calibration signals (cal pulses) and additional hardware (cal network)

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

image product analysis
Image Product Analysis
  • Product header parameters systematically extracted from ASAR products and entered into database for subsequent analysis
  • Parameters extracted are:
    • Internal calibration pulses (P1, P1a, P2 and P3) for each of the 32 rows
    • Product quality parameters (3dB IRF width, sidelobe level, ISLR, peak location, chirp power and scaling factor)
    • Doppler

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

image product database
Image Product Database

32

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

interface
Interface
  • Implemented in IDL
  • Backed by MySQL Database

dummy

dummy

dummy

dummy

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

product analysis
Product Analysis
  • Confirmation of correct functioning of internal calibration
  • Generation of INS files with computed default calibration pulse values
  • Provides overview of main quality parameters
  • Confirmation of correct pointing and correct Doppler estimation

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

calibration pulse analysis wave
Calibration Pulse Analysis - Wave

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

calibration pulse analysis wave p2
Calibration Pulse Analysis Wave P2

Spurious results, if ignored, can lead to problems in processed imagery

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

calibration pulses apm
Calibration Pulses - APM

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

doppler analysis
Doppler Analysis
  • In white, 27000 Doppler estimates from Wave Mode Data
  • In red, the predicted Doppler calculated from orbit parameters

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

doppler estimation
Doppler Estimation

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

doppler bias
Doppler Bias

Subtracting the predicted Doppler from that estimated from the image data shows a bias of –54Hz

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

doppler analysis effect of relief
Doppler Analysis – Effect of Relief

Doppler prediction based on WGS84 hence high altitude of Greenland results in an offset

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

internal calibration24

Occasional spurious results

Fall outside threshold limits and are replaced by the nominal values in the processor

Internal Calibration

Wide Swath, SS5, HH

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

calibration pulse phase unwrapping
Calibration Pulse Phase Unwrapping
  • PF-ASAR currently has a problem when unwrapping the phase of the calibration pulse
  • This introduces noise in the elevation gain factor calculation
  • In-house code unwraps correctly and will soon be implemented in PF-ASAR

White: PF-ASAR

Red: In-house code

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

corrupted wave pulses
Corrupted Wave Pulses
  • Normal wave pulses have blocks of 108 samples of constant amplitude
  • Occasional corrupted wave pulses display irregular amplitude

1st ten source packets plotted

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

corrupted wave pulses 2
Corrupted Wave Pulses 2
  • Corrupted pulses change the elevation gain
  • Problem is not restricted to the northern hemisphere
  • Not deterministic meaning that if it were dependent on the timing then it would always appear in the same SWST segment

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

corrupted cal pulses in wide swath
Corrupted Cal Pulses in Wide Swath
  • P2 calibration pulse in wide swath mode is corrupted for sub-swaths 4 and 5

SS1

SS2

SS3

SS4

SS5

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

gain droop compensation
Gain Droop Compensation
  • P2 gain droop compensation is incorrect when the calibration sequence changes (cal order 0 or 1) in Wide Swath mode
  • Lower curve is from PF-ASAR with droop compensation using pre-launch characterization data
  • Upper curve is in-house code and no compensation

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

conclusions
Conclusions
  • Systematic product analysis proving to be extremely useful for:
    • Troubleshooting
    • Health checking
    • Consistency checking
    • Updating processor parameters
  • So far over 2500 products ingested
    • 949 IMM
    • 1346 WVS
    • 213 WSM
    • 57 APM

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

conclusions 2
Conclusions 2
  • Antenna in great shape, very good stability
    • 0.25dB tx, 0.4dB rx
  • Doppler tracking error ~50Hz consistent with 10-15 mdegrees of mispointing
  • Problem with noisy calibration pulse gains identified due to phase unwrapping - solution ready
  • Problem with P2 gain droop compensation identified – solution at hand

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002

conclusions 3
Conclusions 3
  • Ongoing problems requiring further analysis:
    • Occasional corrupted Wave pulses
    • Corrupted cal pulses in Wide Swath Mode
  • Further problems with the internal calibration are just starting to be addressed in AP and GM modes

ENVISAT Cal/Val Workshop – ESRIN – 9/13 December 2002