Opened 10 years ago

Closed 10 years ago

Last modified 9 years ago

#201 closed support (fixed)

Support: 5/Nov/2008, Li Zhang, no code (old data)

Reported by: mggr Owned by: mggr
Priority: immediate Milestone:
Component: Support Keywords:
Cc: benj Other processors:

Description (last modified by benj)

Contacted by Dr Li (Lily) Zhang re: some CASI data from '97 and various issues:

  • azgcorr version
  • use of azgcorr parameters
  • necessity of DEM with low altitude differences (20-30m, max 70m)
  • ENVI + HDF loading, finding the geolocation
  • Using GCPs?

Also attempting to fix remaining timing errors in the dataset Lily's using (GB97/14).

Attachments (1)

line2_no_correction.jpg (170.2 KB) - added by mggr 10 years ago.
Snapshot of wobbly bit on line 2, no correction attempted

Download all attachments as: .zip

Change History (14)

comment:1 Changed 10 years ago by mggr

  • Description modified (diff)

Ben handled all of the initial problems, but also noticed that the data had timing errors.

He attempted to acquire raw data from NEODC (on exabyte tape) but apparently the formatting is non-standard. NEODC do not have resources to deal with this at this time.

Bill showed us we could still correct the nav using aznav on a L1B file, but there were some bugs (ticket no?). These have been corrected.

comment:2 Changed 10 years ago by mggr

Lily asked for a timeline on fixes - going to attempt the nav timing fixes this week and will ask NEODC for raw data in case of other problems.

comment:3 Changed 10 years ago by mggr

Dataset in question is GB97/14 (1) Kenfig Burrows (c121XX1b.hdf). Lily also mentioned Whiteford Burrows.

There was also a question on ground data - we passed her the address of the PI as these data aren't collected centrally at this time (#202).

comment:4 Changed 10 years ago by mggr

Retrieved boresight and lever arm offsets from NVacor HDF vector:

lev1/originals/c121011b.hdf = NVacor       [6]  0.02803095 -9.39848e-05 1.19215 1.25737 -3.07019e+00 3.93420
lev1/originals/c121021b.hdf = NVacor       [6]  0.02803095 -9.39848e-05 1.19215 1.25737 -3.07019e+00 3.93420
lev1/originals/c121031b.hdf = NVacor       [6]  0.02803095 -9.39848e-05 1.19215 1.25737 -3.07019e+00 3.93420
lev1/originals/c121041b.hdf = NVacor       [6]  0.02803095 -9.39848e-05 1.19215 1.25737 -3.07019e+00 3.93420
lev1/originals/c121051b.hdf = NVacor       [6]  0.02803095 -9.39848e-05 1.19215 1.25737 -3.07019e+00 3.93420

This is an aznav parameter of -acv 0.02803095 -0.0000939848 1.19215 1.25737 -3.07019 3.93420.

comment:5 Changed 10 years ago by mggr

Note from Bill: in 1997 the, nav both position and attitude was only 1Hz and latterly 2Hz. So the "timing" will never be great''

Attempting a variety of timing tweaks on the offchance anyway, but not looking too hopeful so far.

Changed 10 years ago by mggr

Snapshot of wobbly bit on line 2, no correction attempted

comment:6 Changed 10 years ago by mggr

Line 2, no correction:

Snapshot of wobbly bit on line 2, no correction attempted

comment:7 Changed 10 years ago by mggr

No improvements noted on a scan of times from -4.0s to +4.0s @ 0.1s resolution, testing +/-14s @ 1s.

comment:8 Changed 10 years ago by mggr

+/-14 showed no particular improvements, testing +15 -> +20 to cover any remaining parts of the navigation.

comment:9 Changed 10 years ago by mggr

No improvement noted for +15-20.

Conclusion: timing is as good as it'll get for that navigation data :\ Not much chance of getting a better nav solution at this point either (Ashtech nav, no idea how to process that).

comment:10 Changed 10 years ago by mggr

Emailed Lily with the conclusions and some suggestions for how to proceed if the accuracy is insufficient.

comment:11 Changed 10 years ago by mggr

  • Resolution set to fixed
  • Status changed from new to closed

Lily is going to work with the positioning parameters then use GCPs. Suggested digimap might be helpful too.

Closing ticket.

comment:12 Changed 10 years ago by benj

  • Description modified (diff)

comment:13 Changed 9 years ago by mggr

  • Component changed from ARSF to Support
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