Metadata definition December 12, 2003. Following is the metadata definition of the modified xml metadata files From the Eglin data collect of December 2 and 3, 2003. The stored metadata was modified in the following manner: - added gimbalAzimuth and GimbalElevation - added sensorTwist - reordered all the data by timestamp A metadata file contains an XML metadata element, which in turn contains a series of record elements. Each record element describes the video frames and sensor platform metadata available at a particular instant. Record elements occur in order of increasing time. Each record bears a timestamp in the form cts="TIMESTAMP", where TIMESTAMP is an integer number of milliseconds since Jan 1, 1970 00:00:00. Within a record element there are three frame elements and, optionally, a metadata element. Each frame element describes the video frame acquired at the time specified by the record's timestamp. A frame element is of the form where STREAM is one of the letters A, B, or C, denoting the daylight TV, spotter, and infrared cameras, respectively, and VALID is true or false according to whether a video frame from the sensor was recorded for the time specified by the record's timestamp. The fnum attribute is present if VALID is true; it specifies the frame number within the stream-specific AVI file at which the frame is recorded. If sensor platform metadata was received at the time specified by a record's timestamp, then that record includes a metadata element. The metadata element has the following attributes. Note that all geodetic measurements are with respect to the WGS-84 reference ellipsoid. altitude The height of the aircraft's GPS/INS system above the WGS-84 ellipsoid, in meters. fov The vertical field of view of the camera specified by the sensor attribute, in degrees. fovClock A camera clock value reported by the sensor platform at the time it reports the field of view. gimbalAzimuth The azimuth of the camera optical axes with respect to the aircraft, in degrees. At zero, the cameras are pointed directly ahead. At 90, they are pointed starboard. gimbalClock A camera clock value reported by the sensor platform at the time it reports the field of view. gimbalElevation The elevation of the camera optical axes with respect to the aircraft, in degrees. At zero, the cameras are pointed horizontally with respect to the aircraft. At 90, they are pointed straight up. heading The heading of the aircraft, in degrees. At zero, the aircraft is heading directly north. At 90, it is heading directly east. latitude The geodetic latitude of the aircraft's GPS/INS system, in decimal degrees. longitude The longitude of the aircraft's GPS/INS system, in decimal degrees. pitch The pitch of the aircraft, in degrees. At zero, the aircraft is horizontal with respect to a local plane tangent to the WGS-84 ellipsoid. Positive values correspond to the nose of the aircraft pitching up. roll The roll of the aircraft, in degrees. At zero, the aircraft's wings are horizontal with respect to a local plane tangent to the WGS-84 ellipsoid. Positive values correspond to the left wing tilting up. sensor Which camera the fov attribute pertains to. Possible values are 1 (spotter), 2 (daylight TV), and 5 (IR). sensorAzimuth The azimuth of the cameras with respect to north, in decimal degrees. At zero, the cameras are pointed directly north. At 90, they are pointed east. sensorElevation The elevation of the cameras with respect to the horizon, in degrees. At zero, the camera's optical axes are parallel to a local plane tangent to the WGS-84 ellipsoid. Positive values correspond to the cameras looking up. sensorTwist The rotation of the cameras about their optical axes, in degrees. At zero, a line perpendicular to a local plane tangent to the WGS-84 ellipsoid projects to a vertical line in each camera's image plane. Positive values correspond to a counter-clockwise (viewed from behind the camera) rotation of the cameras about their optical axes. targetLat The estimated geodetic latitude of the point at which each camera's optical axis intercepts the terrain surface, in decimal degrees. targetLon The estimated longitude of the point at which each camera's optical axis intercepts the terrain surface, in decimal degrees. targetRange The estimated range to the point at which each camera's optical axis intercepts the terrain surface, in nautical miles. targetWidth The estimated width of the region of terrain observed by the camera [sensor# ], as measured horizontally across the camera's field of view, in meters. timeTag The time reported by the aircraft's GPS receiver. It represents ellapsed seconds since the start of the week, as measured by GPS time. velocityEast The speed of the aircraft's GPS/INS system in the east direction, in meters / second. velocityNorth The speed of the aircraft's GPS/INS system in the north direction, in meters / second. velocityUp The speed of the aircraft's GPS/INS system in the vertical direction, in meters / second. Orientation of the cameras is specified redundantly by the values of roll, pitch, heading, gimbalAzimuth, gimbalElevation, sensorAzimuth, sensorElevation, and sensorTwist. Orientation of the cameras with respect to a local vertical coordinate system can be computed by compounding the rotations corresponding to heading, pitch, roll, gimbalAzimuth, gimbalElevation in that order, or, equivalently, by compounding the rotations sensorAzimuth, sensorElevation, sensorTwist in that order .