HyperTrack™
Software Instruction
115
Quasonix, Inc.
TM and ground station equipment. This RF signal is radiated from the subreflector to the feed. Unlike “test signal
injection” schemes, where the AM signal is inserted somewhere downstream of the feed, the GSA exercis
es every
single component in the RF path. No defect or failure can be overlooked.
The hardware to support the GSA is mounted on the antenna, above the azimuth rotary joint. The key components of
the GSA are a custom Quasonix transmitter (capable of functions not supported by our standard transmitters, such as
amplitude modulation) and a small L/S/C band button antenna mounted to the exterior of the feed at the vertex of
the reflector.
When driven by the GSA, the antenna follows the synthetic target across the synthetic sky, and the receivers
demodulate the ARTM waveforms for downstream processing by the decommutators. If there are dropouts caused
by any signal characteristics or limitations in the ground station, including tracking errors, the GSA will produce
them.
To illustrate how the GSA source creates RF signals that look like a real target, a simple two-state SCM example is
shown in Figure 135. By increasing the amplitude of the transmission in conjunction with the right beam SCM
scanning, it can cause the HTAC to estimate the target being to the right and therefore cause antenna to actually
move in that direction. By monitoring the actual position of the antenna, the GSA can continually synthesize the RF
response as if an actual target was present.
Figure 135: GSA Generates the Actual RF Signal with Correct AM
Since the GSA and GSA transmitter synthesize RF, it truly checks the entire RF and TM system. The GSA can also
accept an external TM test stream to also exercise downstream ground station processing if desired. This capability
provides for end-to-end total ground station checkout without a traditional boresight. A block diagram showing the
GSA architecture is shown in Figure 136.
