simulated tracking and tactical situations
resemble actual operations. Data extracted during
these simulated exercises can be used to verify the
accuracy of operator tracking and system operation.
The VSS is a computer-controlled device capable
of generating antenna position data and triggers
(sweep data), and radar video signals including
simulated tracks, IFF/SIF, receiver noise, and sea
clutter. Only the generation of video signals may be
computer controlled; all other VSS functions are
controlled from the VSS front panel, shown in figure
Radar Sweep Simulation
The VSS can generate its own antenna position
data or use a ships radar as a source. If a ships radar
is used, the LIVE RADAR SOURCE switches are
used to select the source radar and video level. The
VSS then receives antenna position data and triggers
from that radars RAC via the RDDS. The antenna
position data (digital azimuth) and triggers are used to
determine the generation times for video signals.
The VSS contains its own synchro assembly,
which generates synchro azimuth and triggers to the
VSS RAC. The output of the VSS RAC is in turn fed
back to the VSS via the RDDS for coincidence
The VSS simulated antenna rotation
(RPM) and timing signals are controlled from the
SIMULATED RADAR switches. To activate the
servo assembly, both the E-REF and ANTENNA
switches must be on.
Radar Video Simulation
The VSS receives video control data from the
computer in message form. The output data defines
the simulated video azimuth (bearing), range, and
intensity. The VSS stores the output data in its track
storage and compares the data with the digital azimuth
and sweep data received from the RDDS. When the
simulated video data and the digital sweep data are
coincident, the VSS generates the ordered video
signals and transmits them to the RDDS. Console
selection of the VSS radar and video level allows
display of VSS video and sweep.
The video output of the VSS is made up of three
types of video: live video, live and simulated (mixed)
video, and simulated video. The live video output is
isolated from the simulator. The live and simulated
output is made up of simulated tracks intermixed with
live video passing through the VSS. Simulated video
is made up of computer-generated video only.
Manual control of the simulated video
characteristics is provided by the SIMULATED
VIDEO switches. These switches allow the generated
video to display characteristics that are similar to live
radar video. The VIDEO DURATION (µSEC) switch
controls the intensity (pulse length) of the simulated
video return. The sharpness of the return is controlled
by the IF BANDWIDTH switch. The sector width of
c o n t r o l l e d b y t h e R A D A R
BEAMWIDTH DEGREES control.
TEST MESSAGE GENERATOR (TMG)
The test message generator (TMG), shown in
figure 3-25, is used to generate simulated computer
output data for testing and troubleshooting display
Normally contained in the PANG
cabinet, the TMG is removable for its testing and
troubleshooting role. The TMG maybe connected to
the equipment under test by a jumper cable. This
permits greater freedom of action for maintenance
personnel in troubleshooting individual devices, such
as a PPI console.
The TMG can simulate any desired computer
output data message up to four data words in length.
Coding of TMG data is controlled by word group
switches on the TMG control panel.
The TMG is capable of operating in five different
The mode selection allows for great
flexibility when testing or troubleshooting the display
Free Run Mode
The free run mode of operation repeats an
operator-selected four-word message approximately
every 400 microseconds. In this mode, the TMG may
be used with any display equipment.