With a satellite or GNSS receiver highlighted in the Object Browser,
click the 
button
or select Antenna from the Object Catalog to attach an antenna to the
satellite or GNSS receiver. You can set the following properties
for an antenna:
| Antenna Properties | |
|---|---|
| Property | Description |
| PhaseCenterLocation | This is for a space-based object only. It creates an offset of the antenna phase center from the satellite's center of gravity in the satellite's body frame. Specify the X, Y, and Z coordinates in the selected distance unit. |
| PhaseCenterLocation.ModelPhaseCenterVariation | Applies only to an antenna on a GNSS Satellite. It is a read-only setting that reflects the configuration of the GNSS Constellation when the GNSS Satellite was created. A value of true indicates that ODTK will use phase center variations from the Antex File identified in the PhaseCenterLocation.AntexFilename setting. These phase center variations, which are dependent on the frequency and direction between the GNSS satellite and the GNSS receiver, provide small corrections to pseudo-range and carrier phase measurements that may be important for high-accuracy applications. |
| PhaseCenterLocation.ANTEXFilename | Applies only to an antenna on a GNSS Satellite. It is a read-only setting that reflects the configuration of the GNSS Constellation when the GNSS Satellite was created. It shows the name of the file containing mean phase center and phase center variations. The standard file from IGS, igs14.atx, contains antenna mean phase center offset and antenna phase center variations for all of the currently operational GNSS satellites. IGS also retains historical versions of ANTEX files in an archive folder, listed in order by GPS week. |
| PhaseCenterLocation.Estimate |
Applies only to an antenna on a satellite-based GNSS receiver. Set it to true to estimate antenna phase center location in the filter and smoother or to randomly deviate in the simulator. ODTK uses a single phase center for both carrier phase and pseudo-range measurements. ODTK supports the estimation of phase center when using carrier phase, pseudo-range observations, and GNSS navigation solution measurements. Use the SigmaX, SigmaY, and SigmaZ attributes to specify a priori position uncertainty in the respective directions of the satellite body frame. |
| Boresight | You can use this for an antenna attached to a space-based GNSS receiver only. It identifies the reference direction to measure elevation from the user to the GNSS spacecraft. Use the elevation and azimuth fields to specify the direction of the antenna boresight in the spacecraft body frame. An elevation of 90 degrees specifies an antenna boresight along the body-fixed Z axis and azimuth is measured from the body-fixed X axis positive in the direction of the body-fixed Y axis. The MinElevation is used to specify a minimum elevation of the vector from the antenna to the GNSS satellite with respect to the specified antenna boresight direction. The antenna to GNSS vector has an elevation angle of 90 degrees with respect to the boresight direction when it is collinear with the boresight direction. |
| AntennaOffsets | Applies only to an antenna on a facility-based GNSS receiver. You can enter the offset of the antenna phase center location from the Facility.Position in either Earth Centered Fixed (ECF) coordinates or in Height and horizontal (East, North) eccentricity. If in ECF coordinates, specify the X, Y, and Z offsets in the selected distance unit. If in H/E/N, specify the Height, East, and North offsets in the selected distance unit. |
| AntennaID | Enter an integer greater than zero. |
| TrackingIDAlias |
You can use an optional string to provide linkage to a textual ID in RINEX observation files. The antenna identifier comes from the leading string on the (ANT # / TYPE) line in the RINEX file header. If this identifier is an integer, then you can use the AntennaID to properly link the measurements to the correct antenna and no value for TrackingIDAlias is required. Identifying the antenna location associated with GNSS measurements is important to obtain the most accurate orbit determination results. This property is only available for antennas hosted on GNSS Receiver objects. |