1 Alternate Methods for Service Package/Trajectory Prediction Correlation John Pietras SMWG Colorado Springs January 2007

2 Red-1 Method UMCM Add Trajectory Prediction N applicable to (t x – t y ) Create Service Package for (t n – t m ; t x < t n and < t m < t y ) referencing N Alternate Trajectory Predictions O - X applicable to (t x – t y ) optional [Trajectory changes to a predefined alternate] Apply New Trajectory to Service Package, referencing O - X [Trajectory changes sufficiently to require update a new trajectory] Add Trajectory Prediction Y applicable to (t x – t y ) Apply New Trajectory to Service Package, referencing Y Delete Trajectory Prediction N [O..Y]

3 Problems with Current Approach Current networks don’t require their users to tell them to update the trajectories, they just do it –Increased workload for “UM”s compared to current practice Current networks don’t require users to manage the trajectory data stored at CM, they just discard (or archive?) outdated/overridden trajectory prediction data –Again, increased workload for “UM”s compared to current practice

4 Alternate Method 1 (NASA SN, GN, AFSCN) UMCM Trajectory Prediction N applicable to (t x – t y ) Create Service Package for (t n – t m ; t x < t n and < t m < t y ) [Trajectory changes sufficiently to require update a new trajectory] Trajectory Prediction O applicable to (t x – t y ) CM overlays new points over previous ephemeris (if any) for the applicable Period. Only one trajectory maintained for any given period No identification of explicit trajectory file; orbit number used for rough correlation CM makes best effort to generate and use new Acquisition based on TP O CM automatically discards/ archives outdated/ overridden trajectory data

5 Alternate Method 2 for Support of Stable Orbit S/C (some commercial TT&C nets) UMCM Create Service Package for (t n – t m ; t x < t n and < t m < t y ) CM pulls new vectors from Server at at least the agreed Update frequency No identification of explicit trajectory file; orbit number used for rough correlation UM and CM establish update frequency for state vectors Vector Server

6 Some Ideas (1) Add an alternate approach to support Method 1 –Service Agreement specifies that this is the approach that is used –Service Package has a null trajectoryRef value Impacts Service Package Service (allow orbit number as an option?) – Allow multiple trajectories for the same time period to be added at CM More flexible than current network’s current practice More than one trajectory may have to be optional capability of CM Create new “Apply Alternate Trajectory” operation for UM to tell CM to switch –(Optional?) notification from CM when updated data is available operationally Similar to previously-discarded concept, but less ambitious (doesn’t identify individual affected Service Packages)

7 Some Ideas (2) Add an alternate approach to support Method 2 –Service Agreement specifies that this is the approach that is used –State vector retrieval location specified in Service Agreement –Service Package has a null trajectoryRef value