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offset_pwr_tracking vs. offset_pwr_tracking2

Added by Thorsten Seehaus over 8 years ago

Hi,

I got a problem with the "new" offset_pwr_tracking2 command. I want to use it to obtain a first guess of the offset field (with out providing an init. offset field). However, the result differs strongly from the "old" offset_pwr-tracking command. Much less offset estimates are accepted (using the same parameters)

here the lines:

offset_pwr_tracking $input1 $input2 $input1.par $input2.par $outoff $t_offsN $t_snrN $loc_rwin $loc_azwin - $n_ovr $thres $rstep $azstep 1 $n_tracking_range 1 $n_tracking_az - - - $t_ccsN

output:
....
search line: 2 SLC-1: 61 SLC-2: 210 azoff_init: 149 roff_init: -24 pflg: 0
offset estimates accepted: 533 out of: 544

search line: 3 SLC-1: 91 SLC-2: 240 azoff_init: 149 roff_init: -24 pflg: 0
offset estimates accepted: 531 out of: 544
..... 

offset_pwr_tracking2 $input1 $input2 $input1.par $input2.par $outoff $t_offsN $t_snrN - - $loc_rwin $loc_azwin - $n_ovr $thres $rstep $azstep 1 $n_tracking_range 1 $n_tracking_az - - - $t_ccsN

output:
.....
search line: 2 SLC-1: 61
offset estimates accepted: 151 out of: 544

search line: 3 SLC-1: 91
offset estimates accepted: 155 out of: 544
.......

I dont understand, why I get 2 different results (the old command is doing fine)


Replies (4)

RE: offset_pwr_tracking vs. offset_pwr_tracking2 - Added by Thorsten Seehaus over 8 years ago

Add on:
offset_pwr_tracking also returns:

*initial offset estimate (range, azimuth): -25 149 *
in the parameter list after starting it.


offset_pwr_tracking2 does not list initial offset estimate

RE: offset_pwr_tracking vs. offset_pwr_tracking2 - Added by Charles Werner over 8 years ago

Hello,

offset_pwr_tracking2 has a different argument list than offset_pwr_tracking to
permit using a previous offset list

The way to use it is to first start with a very large window (maybe 256) depends
on what your problem is.
that initial offset field should be fairly large. Then interpolate that initial
offset field with interp_ad, and then run it again.
I suggest you read the HTML documentation if you have not already done that.

If you have a data set that you would like me to look at I can do that. (maybe
not too large :)

Best regards,
Charles

RE: offset_pwr_tracking vs. offset_pwr_tracking2 - Added by Thorsten Seehaus over 8 years ago

Hi,
I did a work around and used the old offset_pwr_tracking for the first iteration (incl. interp_ad) and the offset_pwr_tracking2. Now it seems to work out.

Is offset_pwr_tracking2 ignoring the offset in the off.par file (*initial offset estimate (range, azimuth): -25 149 *). Because I used window sizes of 128 px (which is smaller than the init. offset).

Is only the init. offset included in the offset field derived by offset_pwr_tracking? or also the offset information of the offset polynomials?

Cheers

Thorsten

RE: offset_pwr_tracking vs. offset_pwr_tracking2 - Added by Charles Werner over 8 years ago

Hello,

offset_pwr_tracking2 currently ignores the initial offset, though I will
probably change that if no offset parameter file is provided for the initial
offset.
The offset polynomial is not used!

The typical approach is to use a large window for the first iteration,

Best regards,
Charles

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