INPUT CARDS

The Global Set begins with a mandatory subset of three cards on which the user may record any descriptive information concerning the job.

The Option cards which follow, are presented in the document in alphabetic order but not necessarily used in this order unless otherwise specified in the individual case. Information which applies to all arcs could be included in one of the following categories of input cards:

1.

A forcing function description and/or condition input card such as:

• cards which define the gravitational model
• request application and/or modifications of the Earth or planet gravitational potential,
• request application and/or modifications of the Earth tide model.
• request estimation of the gravitational coefficients.

2.

Observation modeling descriptive cards such as:

• cards which require application of various models
• modify and/or estimate parameters which describe the observation equation (polar motion, solid Earth tides, ocean tides and tectonic plate motion.)

3.

Cards specifying models which describe tracking measurement corrections such as:

• antenna or reflector offsets from the spacecraft center of gravity
• choice of tropospheric refraction model

4.

Cards which affect observation modeling.

5.

Input cards controlling the format and the quantity of the listings and the printout.

The Global Set continues with the STAPOS subgroup. Input cards in this subgroup set conditions for solution, constraints and correlations pertaining to stations with available data. The STAPOS subgroup also includes cards containing station positions, geodetic information and planetary parameters for extra terrestrial stations. If the STAPOS subgroup is present it must be terminated with an ENDSTA card.

The Global Set of input cards ends with the mandatory card ENDGLB which also specifies the maximum number of Global parameter estimation iterations and the number of TITLE cards in each arc.

The Arc Set begins with a number of TITLE cards which are mandatory for each run on which the user may include any information pertaining the arc. Information to be included on the rest of the mandatory card subgroup is the coordinate system of integration, number of arc iterations, spacecraft information, start and end time of orbit integration and introduction of the components of orbital elements.

The next subgroup of the Arc Set is a group of Option cards which affects:

1.

The solution itself with information such as:

• editing multiplier
• integration order/step size
• apriori variance/covariance matrix for the satellite elements.

2.

The observation equation with information such as:

• measurement bias and
• station timing bias

3.

The force model with information such as:

• application and/or adjustment of
  • general acceleration
  • drag coefficient
  • solar radiation pressure

4.

The output with information such as:

• output of E or V-matrices
• output required on specified units
• residual file output
• normal point generation control

The next subgroup in the Arc Option cards is called the Data Selection subgroup and it is introduced by the DATA card. This card must be present with any arc requiring data reduction. The cards which follow DATA are very important to the user as an editing tool. One can specify Data Selection and Deletion time intervals, input of meteorological data, application of constant bias observation correction, request data preprocessing and specification of weighting and editing sigmas.

The Data Selection subgroup ends with an ENDARC card which also denotes end of the arc. In case more than one arc are required, the user should start with a new set of Arc TITLE cards.

A detailed description for each card in the Global and Arc Sets is given in the following section. That includes format and function description, default values and units and description of the consequences in case any of these cards is ommitted.

Finally the card ENDALL denotes the end of all arcs and the end of input cards.