The data reduction pipeline is used to process the input data from the source and the telescope to provide accurate position and attitude coordinates for the drone while in flight, synchronized with the telescope data

P1: Alt-az

Description: This table contains the drone's Alt-az coordinates and its distance,  both referenced to a given telescope. Additionally, it includes information, such as the change time, the drone's position in WGS84, and errors associated with the Alt-az coordinates and distance.

Format: ECSV file.

Metadata: Includes the mount that was used.

Fields: 

• ctime:    Change time associated to the data frame                                     (seconds, float64)

• lon:         Longitude of the drone in WGS84                                                       (degrees, float64)

• lat:          Latitude of the drone in WGS84                                                           (degrees, float64)

• height:  Height of the drone above sea level                                                    (meters,   float64)

• Az:          Azimuth coordinate of the drone as seen by the telescope  (degrees, float64)

• Alt:         Altitude coordinate of the drone as seen by the telescope   (degrees, float64)

• Dist:       Distance between the drone and the telescope                          (meters,   float64)

• dAz:       Error of the azimuth coordinate                                                            (degrees, float64)

• dAlt:      Error of the altitude coordinate     (degrees, float64)

• dDist:    Error of the distance                                                                                     (meters,   float64)

P2:  Find targets

Description: These results correspond to the 2D coordinates (x and y) of the targets detected in each frame. This table also contains information related to each target—for example, the frame in which the target's 2D coordinate are being searched, and its 3D coordinates obtained from GPS data. Targets are searched only in frames where the drone is at the desired position.

Format: ECSV file.

Metadata: Includes video's name (flight log's name) and date, start and end frame, as well as the reference frame origin.

Fields:

• targetName: Target's name in format target_x, where x is a number between 1 and 38 (N/A,             string)

• frame:   Frame's number where the target is being searched.  Values goes from start to end frame   (N/A,              int64)

• x: Position along the X-axis at which the target is found in the frame  (pixels,      float64)

• y:                            Position along the Y-axis at which the target is found in the frame  (pixels,      float64)

• LAT_GPS:            Latitude of the target based on fixed GPS reference (degrees, float64)

• LON_GPS:           Longitude of the target based on fixed GPS reference (degrees, float64)

• HEIGHT_GPS:   Altitude of the target based on fixed GPS reference (meters,   float64)

P3:  Find camera position and attitude

Description: This table contains the estimated position and attitude of the camera for each frame obtained using the 2D coordinates of the targets detected in P2. For each frame,  the rotation and translation vectors (rvecs, tvecs) that describe the camera’s orientation and position relative to the target's coordinate system are stored. The vectors are calculated using an ENU based coordinate system. 

Format: ECSV file.

Metadata: Include general information about the flight and video used to generate the table, such as camera calibration data, date, names of the flight and video, and reference point of the ENU coordinate system.

Fields: 

• frame:  Frame number. Values goes from start to end frame (N/A,              int64)

• rvec:   X, Y and Z components of the rotation vector for each frame (radians,   float64)

• tvec:   X, Y and Z components of the translation vector for each frame       (meters,   float64)

P4:  Align GPS-Video

Description: These results include frame number, change time and synchronized tvec in the ENU coordinate system obtained from the GPS data stored in the drone. The drone's position is transformed from geodetic to the ENU coordinate system, and then the data is interpolated to match the number of frames. Next, the drone's position is correlated with the tvecs from P3 which have also been converted to the ENU coordinate system.  This enables the synchronization of GPS and photogrammetry data to correct the rvec values in P5.

Format: ECSV file.

Metadata: This table's metadata includes information about the camera calibration parameters, date and names of the video and flight, as well as the reference point in geodetic coordinates used for the transformation to ENU coordinate system.

Fields:

• frame:  Frame number. Values goes from start to end frame (N/A,   int64)

• ctime:     Change time (ctime) associated to the frame (seconds, float64)

• E:  Drone's position along the E-axis, equivalent to X coordinate of tvec (meters,   float64)

• N: Drone's position along the N-axis, equivalent to Y coordinate of tvec (meters,   float64)

• U: Drone's position along the U-axis, equivalent to Z coordinate of tvec (meters,   float64)

P5: Position and attitude corrected

Description: This table presents the results of the correction applied to the rotation vector (rvec) using the drone's position obtained in P4. Additionally, it includes the translation vector (tvec) previously obtained, along with the corresponding frame and change time (ctime).

Format: ECSV file.

Metadata: This table's metadata includes information about the camera calibration parameters, date and names of the video and flight, as well as the reference point in geodetic coordinates used for the transformation to ENU coordinate system.

Fields:

• frame: Frame number. Values goes from start to end frame (N/A,   int64)

• ctime: Change time associated to the frame (seconds, float64)

• tvec:   X, Y and Z components of the translation vector obtained in P4 for each frame (meters,   float64)

• rvec: Corrected X, Y and Z components of the rotation vector for each frame (radians,   float64)

P6: Merge Alt-az and attitude results