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The Automatic Precise Point Positioning Service of the Global Differential GPS System
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APPS with Attitude Quaternions

  This unique feature goes hand-in-hand if your RINEX data is in motion from airplane or helicopter and you are processing in Kinematic mode. Aerial movements in conjunction with your own quaternion file can help improve your PPP solution.
  APPS now offers the user an option to upload your own quaternion file. If this file is not provided, APPS will generate it from your RINEX file. User-provided attitude quaternion file must be strictly ordered in time as a timeseries. That is, records for all objects at a particular time must be continguous.
  Note: We refer to an epoch we call J2000GPS.
  • J2000GPS is distinct from the epoch J2000.0, which the IAU 1994 Resolution C7 recommends be defined at the geocenter and at the date 2000 January 1.5 Terrestrial Time(TT), where TT = TDT.
  • J2000GPS is also distinct from the date 2000 January 1.5 UTC time, which we can refer to as J2000UTC. Exactly 13 leap seconds separate these epochs, i.e.: J2000GPS = J2000UTC - 13 = 2000-01-01 11:59:47.000 UTC
  • Times before and after J2000GPS are descrived in GPS seconds around this epoch, i.e., continuous time.
  User-provided Attitude Quaternion file must have the following format:
  Example: (all should be in one line)
E GPS23 403261200 0.000000000000000E+00 4.213090921042242E-02 
1.449777480113355E-01 7.188055942732944E-01 -6.786198911851030E-01
Fields 0-7 are REQUIRED.

0   Typically E for Earth-Fixed, I for Inertial, B for body-fixed.
    Note that nothing inherently limits this to a single character
    in order to allow for more descriptive or exact coordinate systems.
1   Name of object (satellite, station, ??? ); white-space is not
    allowed in the name.
2   Integer (t_i) seconds past J2000GPS. To get GPS seconds past GPS
    week 0 second 0, ( 6-JAN-1980 00:00:00.0000), add 630763200; we
    assume this is a signed int in C++.
3   Float seconds (t_f) past t_i, double for C++.
4   Unit attitude quaternion, scalar component
5   Unit attitude quaternion vector, i component
6   Unit attitude quaternion vector, j component
7   Unit attitude quaternion vector, k component
  All lines with the same name (field 1) must be time ordered
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