N02A
The 2.8-m NISAR corner reflector N02A was removed August 21st, 2024, due to excessive damage. It was replaced with a 2.4-m triangular corner reflector and ring-stand mounted on September 14, 2024. This target is currently still aligned for the ascending track of NISAR’s left-looking SAR sensor however its new location is 380 meters south and 50 west of its original location. It is anticipated that a ring stand mount will subject the corner reflector with less frost heave. The 2.8-m NISAR corner that was removed has been repaired and is now installed at Donnelly Dome and has been renamed as N04A.
It was discoverd that in October, 2024 this corner reflector was nudge possibly signicantly by livestock. We plan on resurveying it in the new future. The livestock are not expected to interfere until possibly again in summer 2025.
N31A
On October 1, 2024, maintenance was performed on the ringstand mounted 3.0-m triangular trihedral corner reflector N31A located 15 kms southwest of Fairbanks. The bottom base of the corner is now supported (removing warping) and the tilt was remeasured to be 17.40 ( up from 13.88 ) and the azimuth heading was remeasured to be 329.00 ( was 329.75 ).
The position of the vertex was also remeasured and the change was found to be +1.1/+0.5/-3.4 cm in E/N/V. The coordinates have been updated on based on this survey. This target is still aligned for the ascending track of NISAR’s left-looking SAR sensor. It is mostly east looking.
N32A
On September 12th, 2024, maintenance was performed on the 3.0-m triangular trihedral corner reflector N32A at Fort Greely. The left guywires were re-installed, and the bases are reinforced. No new GNSS measurements were obtained. The tilt was remeasured to be 18.37 ( up from 17.57 ) and the azimuth heading was remeasured to be 216.25 ( was 214 ).
On October 10th, 2024, the position of the vertex was remeasured and the change was found to be -8.3/-9.6/+0.5 cm in E/N/V. The coordinates have been updated based on this survey. This target is still aligned for the descending track of NISAR’s left-looking SAR sensor. It is mostly west looking.
S01A and S02A
On September 11th, 2024, we installed two 0.8-m square trihedral corner reflectors at the University of Alaska on the T-field. The northern one (S02A) is mostly East facing, and the southern one (S01A) is mostly West facing. The tilts and headings are optimal for a right-look sensor, for example Sentinel. In the Spring of 2025, these targets will be rotated and re-aligned for NISAR’s left-looking sensor.
N01A
On September 13, 2024, we performed maintenance on the NISAR 2.8-m tringular trihedral N01A at the Panoramic Bison Range. We believe it was installed with an azimuth of 215, however it may have been rotated by animals to 204 degrees. During this maintenance, we rotated it to 216.3 degrees azimuth. It is mostly west-facing and its tilt did not change significantly; it is now 17 degrees. This target is aligned for the descending track of NISAR’s left-looking SAR sensor.
N03A
On September 13, 2024, we performed maintenance on the ASF's 2.4-m tringular trihedral N03A at the Panoramic Bison Range. We remeasured its location and it is now 42 cms higher than when it was installed in October, 2023. The measurments in horizontal are less than 1 cm East and -3 cms North from its October, 2023 determined location. It is mostly east-facing. This target is aligned for the ascending track of NISAR’s left-looking SAR sensor.
N04A
On September 12, 2024, we installed the repaired NISAR 2.8-m tringular trihedral that was N02A. This new location is west of Donnely Dome and this CR is now called N04A. It is attached to wooden platform in the middle of meadow. This target is aligned for the ascending track of NISAR’s left-looking SAR sensor. It's tilt is 12.5 degrees and the azimuth heading is 325.2 degrees.
N05A
On September 14, 2024, we measured an ASF 3.0-m tringular trihedral at the University of Alaska Ag Field. This CR is now called N05A. It is on an ASF ring stand and is aligned for the descending track of NISAR’s left-looking SAR sensor. It's tilt is 12.7 degrees and the azimuth heading is 214.0 degrees.
