Sonobuoys Flashcards
What is the nomenclature for the buoys?
BT Buoys: AN/SSQ-36B
DIFAR: AN/SSQ-53F/G
DICASS: AN/SSQ-62E/F
What can you CFS for a DIFAR buoy?
RF channel, RF pwr (on/off), Life, hydrophone (std DIFAR, shallow omni, calibrated omni), acoustic automatic gain control (fast/slow/off), GPS (Enable/Disable)
What can you CFS for a DICASS buoy?
RF channel, RF pwr, audio (ping) frequency, depth, GPS (enable/disable)
What radio does CFS work with?
UHF downlink. So if your UHF radio is in secure, you will not be able to CFS your buoys.
What are the different passive sonobuoy processing modes?
LOFAR/DIFAR Omni Directional Steered Cardioid Orthogonal Cardioid Synthetic Omni DEMON (high or low)
LOFAR/DIFAR Omni
provides spectrogram (gram) and automatic line integration (ALI). Bearing info is not produced and parameter tracks are not subject to phase-lock constraints
DIFAR Directional
provides gram, ALI, and bearing vs. frequency
DIFAR Steered Cardioid (theoretical gains?)
Sonobuoy cardioid is a beam which is formed in the AP using the sonobuoy’s omni, N/S, and E/W channels. The main beam provides a theoretical 4.77 dB gain. The null response provides an approx -10 dB response relative to non-cardioid DIFAR processing.
DIFAR Orthogonal Cardioid
Five ALI and gram data sets are produced - one for the omni channel and one for each of the 4 cardioid beams pointing to the cardinal hdgs. The benefit is that there is an assured beam pattern gain regardless of the target bearing, ranging from 4.77 dB best case to a theoretical 3.4 dB worst case (at the 45 of a cardinal hdg)
DIFAR Synthetic omni
Provides gram, ALI, and BVF data on a synthetic omni beam
How many bins are in a band?
256
How many bands per processing option are supported by the AP
16
What is Octave Processing?
Constant Percentage Resolution (CPR), provides a logarithmic frequency scale across each octave. The center frequency and width of each bin increases by the same ration (0.27% per bin) across the entire processing range.
Full band?
Octaves 1-8
Half Band?
Octaves 0-7
Quarter band?
Octaves 0-6
Eighth band
Octaves 0-5
What are Vernier bands?
provide a linear frequency scale covering a fraction of the octave containing the center frequency. Each V4 band covers 1/4 of the octave and each V8 band covers 1/8th of the octave. The width of the band is set based on the octave containing the center frequency.
What are Constant Resolution Bands?
CR processing provides a constant bin width across the entire processing range independent of the center frequency. Six CR bands are available, CR4-CR9
What are the different gram rate selections?
1.25 seconds, 2.5 seconds, 5 seconds, 10 seconds. Shorter gram time provides improved performance against dynamic frequencies or transient signals. Longer gram time selections provide for a longer total gram history window and improved performance against relatively stable frequencies
What does DICASS signal processing produce?
range/bearing and range/Doppler display data
DICASS waveforms?
CW-short, CW-medium, CW-long, FM
What colors indicate doppler?
Red: up Doppler
Blue: down Doppler
Green: zero Doppler
What is Fine Bearing/Frequency function
Measures the frequency and bearing for the highest amplitude signal within +/- 10 frequency bins of the cursor frequency. The measured frequency and bearing are displayed at the top of the sonobuoy Analysis display
