GB18/00, flight day 184c/2018, Alconbury

[dac]

Data location: /users/rsg/arsf/arsf_data/2018/flight_data/nerc-arf_internal/GB18_00-2018_184c_Alconbury

Data arrived from NERC-ARF via hard drive on 13/07/2018

Scientific objective: Internal boresight flight

Priority: Urgent

PI: NERC-ARF

Issues flagged by unpacking scripts:

• Don't have logfiles for all Fenix lines (missing 10 - 13)
• Owl capture data missing darkframes

Sensors:

• Fenix (requested, flown)
• OWL (requested, flown)
• Phase One (not requested, flown)

[asm]

Navigation Processing

Started. Downloaded basestation data using ​OS National GPS Network. Identified closes station as SNEO. Concatenated files, downloaded .epp files using IPASTC for another base and did the basestation verification:
Lat: 52 11 07.33149
Lon: -0 06 44.96866
EllHeight: 121.068 m

[asm]

Navigation Processing

Processed via IpasTC with the data interpolated to 0.5s. Good results for position separation (under 0.2 m during data acquisition) and ambiguity fix 2. Accuracy clearly within limits. Files copied, navigation processing finished.

[asm]

General Checks

Main output from the unpacked checks:
-Last timestamp for a few nav Fenix files appears too early.
-Great differences on Fenix fps and fps_set
-No darkframes recorded for Owl

[wja]

Fenix Processing

Fenix boresight calibration under way. Will use SRTM/LiDAR composite DEM generated for previous boresight calibration flight (2018 128).

[asm]

Owl processing

Started. Have stitched files using the DARKREF files. Only have T2 cal files for line 1 and 5. Have symlinked those T2 in the other dirs as this is project is only needed for assessing the boresight values.

[asm]

Owl boresight

Found SCT values:

Flightline	OWL
1	No usable data
2	2
3	3
4	2
5	2
6	2
7	2
8	2
9	3
10	2
11	2
12	2
13	2
14	2
15	No usable data

Previously found boresight values look very good. Will spend some time trying to see if I can get an even better accuracy using lines flown at lower altitude 11, 12 and 13.

[wja]

Fenix Processing

Current progress:

SCT values currently:

Flightline	SCT Value
1	2.02
2	2.01
3	2.02
4	2.01
5	1.02
6	TBA
7	1.00
8	2.00
9	2.03
10	TBA
11	TBA
12	TBA
13	TBA

TBA: Flightline 6 is failing to process due to DEM not covering nav file. It looks like it has a considerably large negative SCT value.
Flightlines 10-13 appear to have large negative SCT values (~-40), although these values they are currently not improving data quality and features have axagerated areas in the along flight direction.

[wja]

Fenix Processing

Flightline	SCT Value
1	2.00
2	2.00
3	2.00
4	2.00
5	1.00
6	2.00
7	1.00
8	2.00
9	2.00
10	2.00
11	-
12	2.00
13	-

The issue on the previous comment with processing flightline 6 has been resolved by using a newly generated ASTER DEM - ensuring the flightline area is covered. This data no longer uses the EA/SRTM DEM used during the previous calibration (flight 2018 129)

Flightlines 10 - 13 have been recorded using an incorrect FPS value of 30.960 (should be 53.000). Flightlines 10 and 12 have been successfully processed without the navigation file, however flightlines 11 and 13 have timing errors which would be resolved by manually finding their SCT values.

Flightline 4 has a slight timing error.

The flightlines without errors show that there has been no significant change with the boresight values documented for flight 2018 129. There are as follows:

Pitch: +0.40
Roll: -0.76
Heading: +0.55

[asm]

Owl Boresight

I am happy with the originally found boresight values:
Pitch, roll and heading = 0.28 0.17 0.20

It looks there is a small offset for some lines, specially 12 and 13 with are low altitude but if I try to make a better alignment with other boresight values it creates bigger misalignments in other flightlines so I think those are the best values.

[asm]

Fenix Boresight

I did double check the Fenix boresight values. They look very good.