Search found 9 matches
- Tue Sep 08, 2026 3:46 pm America/New_York
- Forum: Home
- Question: NISAR geolocation error .. or plotting error?
- Replies: 2
Re: NISAR geolocation error .. or plotting error?
Thanks for reporting your observation. Yes July 10 product for this specific frame has known issue and will be reprocessed in future. Due to an edge case in raw data processor, the raw data may be shifted when there is a discarded/missing pulse and that impacts the downstream products. The issue wil...
- Thu Aug 27, 2026 11:11 am America/New_York
- Forum: Home
- Question: Region-scale integer-cycle inconsistency in a distributed P05023 GUNW, identified by a five-acquisition loop-closure net
- Replies: 4
Re: Region-scale integer-cycle inconsistency in a distributed P05023 GUNW, identified by a five-acquisition loop-closure
Thanks for posting the plot of connected components. Yes I agree that the connected component in this case is affected by invalid region at the boundary of the swath and is not immediately useful for identifying/correcting unwrapping errors. It looks to me that the unwrapper has not respected the su...
- Mon Aug 24, 2026 2:18 pm America/New_York
- Forum: Home
- Question: Region-scale integer-cycle inconsistency in a distributed P05023 GUNW, identified by a five-acquisition loop-closure net
- Replies: 4
Re: Region-scale integer-cycle inconsistency in a distributed P05023 GUNW, identified by a five-acquisition loop-closure
Thank you for sharing your analysis. Yes users should be aware that there is no easy way to connect possible disconnected islands in an operational system. The provided connected components should help users to identify the separated components and adjust as they wish if they have auxiliary informat...
- Mon Aug 24, 2026 2:01 pm America/New_York
- Forum: Home
- Question: Azimuth offset issues in P05023 processed GUNWs
- Replies: 3
Re: Azimuth offset issues in P05023 processed GUNWs
P05023 provisional products, do not include masks and metrics to help users discard such data. We are indeed adding these metrics in the next delivery. We understand the importance of such metrics for users and will update as they become available.
- Mon Aug 24, 2026 1:54 pm America/New_York
- Forum: Home
- Question: Ghost images in azimuth
- Replies: 1
Re: Ghost images in azimuth
The cause of this issue is same as the post here : https://forum.earthdata.nasa.gov/viewtopic.php?t=8118 The root cause is an edge case in raw data processor which does not correctly time-tag the raw data in presence of discarded rangeline. I confirm that the ghost image disappears after using a new...
- Mon Aug 24, 2026 1:00 pm America/New_York
- Forum: Home
- Question: Azimuth offset issues in P05023 processed GUNWs
- Replies: 3
Re: Azimuth offset issues in P05023 processed GUNWs
Thanks for reporting this issue. The problem originates from corrupted input raw data. Looking at the reference RSLC shows that the image is fully defocused and therefore the interferometry fails to produce any useful product. For example see this RSLC product: NISAR_L1_PR_RSLC_010_077_A_024_4005_DH...
- Thu Aug 20, 2026 12:37 am America/New_York
- Forum: Home
- Question: Coherence seams along whole-degree meridians in NISAR GSLC interferograms over Alaska
- Replies: 2
Re: Coherence seams along whole-degree meridians in NISAR GSLC interferograms over Alaska
Thank you for reporting this edge case. We were able to reproduce the issue. The source of the issue is the DEM at higher latitudes which seems to have a small discontinuity between tiles. We are investigating a possible solution and will update when we have more information.
- Wed Aug 19, 2026 1:50 pm America/New_York
- Forum: Home
- Question: Sharp azimuth offset transitions
- Replies: 1
Re: Sharp azimuth offset transitions
Thank you for reporting this issue. This is a known issue due to missing rangelines or discarded rangelines in raw data and an edge case in raw data processor that does not properly update the time tag of remaining pulses after discarding some (in this case probably only one pulse out of 100s of tho...
- Thu Mar 12, 2026 2:22 am America/New_York
- Forum: Home
- Question: NISAR satellite backscatter coefficient image generation
- Replies: 9
Re: NISAR satellite backscatter coefficient image generation
Thanks for your post. Your approach to convert the GSLC backscatter to sigma-0 is not correct. The RSLC and subsequently GSLC are provided as Beta-0 with respect to an ellipsoid. If you want to convert to sigma-0 you must use the sigma-0 correction factor which is included in theGSLC products at the...