OEM file format

• Orbit Ephemeris Message (OEM) is a CCSDS standard for transferring spacecraft orbit information. An OEM specifies the position and velocity of an object within a specified time range. Its structure and content are specified there.
• Measurements are part of ORaaS orbit determination feature input. Position/velocity measurements have to be upload in files respecting the OEM format.
• ORaaS provides a set of OEM files examples for its Demo. They can be uploaded from our OD demo presentation page.

TDM file format

• Tracking Data Message (TDM) is a CCSDS recommended standard for exchanging spacecraft tracking data. The detailed specifications can be found there.
• Measurements are part of ORaaS orbit determination feature input. Currently, range, range rate and azimuth/elevation measurements have to be uploaded in files respecting the TDM format.
• A subset of the CCSDS Standard is accepted by the ORaaS TDM parser:
  • ORaaS expects files in KVN (keyword-value notation) format.
  • Several segments can be present in a single file, types of measurements can be mixed in a segment.
  • In the Metadata Section, PARTICIPANT_1 is the name (ID) of the station. Information associated to this station is to be given in the json parameter.
  • In a ranging Metadata Section, the item RANGE_UNITS is mandatory. It's value is "km".
  • In the Metadata Section of an azimuth/elevation segment, ANGLE_TYPE is mandatory and must be set to "AZEL". In the Data Section, ANGLE_1 is the measured value of azimuth, ANGLE_2 is the elevation. Both are expected in degrees.
• Extra information is required for a station: location, bias for each type of measurement... It is provided in a json object, its schema can be found in our API documentation.
• ORaaS provides a set of TDM files examples for its Demo. They can be uploaded our OD demo presentation page.