Trigger 2A Description
Sequence: C30, C31
Trigger 2A (Interplanetary Cruise mode with very low bitrate)
This mode is designed to provide an extremely low bit-rate Survey with low temporal
and spectral resolution for periods during cruise when the telemetry allocation
is not sufficient to perform the 200-bps Trigger-28 mode. The bitrate for this
mode is 130 to 140 bps, and is achieved by reducing the HFR duty cycle to every
64 seconds. Other than this modification, this mode is identical to Trigger-28.
No Wideband or Waveform measurements are made. The entire RPWS frequency range
(1 Hz - 16 MHz) is covered. Starting in C29, the 3-axis direction-finding mode
was removed from the HFR and instead, the sensor was changed to the dipole to
increase sensitivity in an effort to detect Saturn emissions.
Receiver Frequency Range Sensors Time between Snapshots
-------- ---------------- ------- ----------------------
LFR 1 - 25 Hz EX, BX 32 seconds
MFR 25 - 12 KHz EX, BZ 32 seconds
HFR 3.6 KHz - 16 MHz EX, EW 64 seconds
LP N/A LP 8128 seconds
This mode is defined by:
Correlations Channels Integ. Size Frequency
Band Ant. Auto- Cross- per Band df Period Rep Steps kHz Start - Stop
---- ---- ----- ------ -------- -- ------ --- ----- ---- ------------
ABC 2E y y 16 n 1000 1 3.6-319 kHz
H1 2E y y 1 n 160 1 18 100 325k-2.0MHz
H2 2E y y 1 n 80 1 71 200 2.0M-16MHz
Bands ABC require 3.16 sec to complete, H1 requires 3.16 sec, and H2 requires 6.00 sec
for a total of 12.32 sec per sweep. However, to keep the bit rate down the HFR only
performs one complete sweep every 64 seconds.
Starting in C26, dust detection using the EZ sensor was added, and
also periodic Langmuir Probe sweeps every 8128 seconds.