Track Data Generation.
The TT&C and 200 MHz Autotracker antennas shall
each generate the following data:
In addition, track data shall be generated by the TT&C antenna as follows:
- Antenna Position.
Azimuth and elevation data shall indicate each
antennas position. This data shall be available for display and processing.
- Data Quality.
Data quality bits shall be generated for each type
tracking data. In addition, track data shall be generated by the TT&C antenna as follows:
- SGLS Range Rate.
Digital range rate tracking data shall be provided
in a 24-bit parallel binary words derived from a 1.8/2.25 MHz phase-coherent
tracking link (256:205 ratio). The doppler frequency of compatable satellites
shall be measured with an error equivalent to a range rate error of
0.2ft/sec rms or less. 2
- SGLS Range Data. Digital range tracking data shall be provided in 30
bit words binary derived from a two-way transmission pseudorandom noise (PRN)
code on the 1.8/2.25 GHz phase-coherent tracking link. The least significant bit
of the range word shall have resolution of 7.8 ft.3
The basic command functions to be performed as shown in Figure 2-7 are as follows:
Digital command data from the STC will be
stored on prepass disk. Commands will be initiated manually by the
Systems Operations Controller as directed by the STC.
- Command transmission.
- Frequency Bands.
The capability shall exist for command
transmission in either the 370 to 470 MHz (low power) or 1.75 to 1.85 GHz
2Range rate is related to doppler count,
Ro as follows:
Note: Resolution of the least significant bit in the readout is equivalent to 0.036 ft/sec at R = 0.
| ||R ||= ||-cRo|
26240N1 + 2048 Ro
|where || || || |
| ||R ||= ||one-way radial velocity|
| ||c ||= ||velocity of light|
| ||N1 ||= ||bias frequency +/- two-way doppler frequency|
| || ||= ||1,048,574|
|when || || || |
| ||Ro ||</= ||37777778 (>/= 4000000 for negative one's complement)|
3Based on a least significant increment of one doppler count,
which is equivalent to approximatley 0.0013 nmi.
Back to main index