Site Tests April 2024

• Monday, April 22th: Drone + GPS are shipped from PUC to SP.

• Friday, April 26th: Federico Nati and Gabriele Coppi arrive to SP. Drone arrives to SP.

• Saturday, April 27th: Rolando Dünner and Matías Rojas arrive to SP

• Sunday, April 28th: Install photogrammetry targets on site, set GPS base stations, measure key points and construct coordinate system. Fly drone with source OFF to check flight program and test telescope settings and data taking.

• Monday, April 29th: BIG DAY

  • ALMA engineering time 9:00 -- 13:00 h

  • Perform as many standard flights as possible, and stop at some point to run tests with ALMA:

    • Standard flights: 

      • Use the regular alt-az flights while the telescope scan at constant altitude across the drone's path. 

      • The drone will fly in a circular path forming an arc at 500 meters from CLASS, spanning +- 4.5 degrees in altitude. 

      • Repeat these flights alternating the 90 and 150 GHz sources. 

      • Rotate the CLASS boresight angle in 15 degrees after every 2 flights (90 and 150 sources), starting from -45 degrees in both CLASS1 and CLASS2 mounts.

      • SO should do similar scans, but with their HWP on, so no boresight rotation is needed.

    • ALMA flights:  

      • The drone will fly up to 400 m above ground and 300 m south from CLASS and point to ALMA

      • Repeat the flight once with the 90 and 150 GHz sources. 

      • Coordinate with Giorgio Siringo by radio.

• Tuesday 30th: Perform source OFF flights to test the pointing accuracy and try different flight programs, such as source roll rotations. Depending on ALMA, we might get green light to do more source ON measurements.

• Wednesday, May 1st: The wind was too high to fly the drone. We remeasured the coordinates of the targets and packed.

First day of the campaign: we setup the GPS system based in a location close (but not the same) to the place used in February 2023, because it was impossible to find the exact same place. After setting up the main GPS base station, we measured the location of the drone RTK base station, but did not attempt to reset its coordinates to align both coordinate systems, so they will need to be aligned offline during data processing. Their coordinates were:

Coordinates of the drone RTK base station

• According to the drone RTK: -22.9611325, -67.7872707, 5137.845

• According to the main GPS system (20240428): -22.96119692, -67.78739273, 5136.978

• According to the main GPS system (20240501): -22.96119708, -67.78739251, 5136.893

We placed the photogrammetry targets in the area and measured their positions using the main GPS, but there were 5 targets that could not be measured because "we couldn't find them".

We also measured the coordinates of all the pads of the SAT ground screens. Note that we labeled them incorrectly: SAT1 -> SAT3 and SAT3 -> SAT1.

We made a test flight using the 150 GHz source OFF, and only the camera ON to check the flight program and the video settings. The flight program was centered on CLASS (POI), scanning +- 10 deg around 45 deg elevation and at 180 deg azimuth. The flight log file is "FLY591.DAT" and the video is XXX.

We performed several flights, some in coordination with ALMA to check for possible contamination signals, and some regular calibration flights.

We performed several calibration flights. The first 3 flights had problems with the Gimbal being unbalanced, and thus unstable. The 4-5th flights were OK, and the 6-8th flights were poiting to SAT3, flight at different distances from the telescopes

From flight FLY605: https://drive.google.com/file/d/1z9Dh_2pBKascC3pP2uJGTtgAv238NMWM/view?usp=sharing