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Hydrophones Projectors Echo Sounders Sidescan Sonar Telemetry & Acoustic Releases Custom Design Calibration |
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The Portable
Echo Repeater System (PERS)
is a compact and versatile system for the performance evaluation of a
wide range of active and passive sonar.
PERS has been designed to be hand-deployed from small vessels
with few facilities - the transducer assembly is a small lightweight
unit containing both projector and
hydrophone. The surface end
of the system includes a rugged, portable, power amplifier unit and a
controlling computer. PERS includes many of the powerful
features of the Chelsea Technologies Group Versatile
Acoustic Source System (VASS) but without the complexity of a towed
format obviating the need for larger vessels. PERS is controlled by an
easy-to-use Graphical User Interface commanding the Digital Signal
Processor which is used to Echo Repeat, Transpond, and produce
Calibrated transmissions with up to 24 Tones simultaneously. PERS provides a highly versatile and
flexible sonar test system that is configured by simple mouse or
keyboard selections. In addition to instant configuration changes, via
its Microsoft Windows 98 interface, PERS allows desktop set-up of
complete trials programs in advance hence avoiding costly errors in
signal definition during calibration trials. |
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Specification - General (applies to all modes) |
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Modes |
Source, Echo Repeat,Transpond, Sequence, Sequence (Advanced System) |
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Transmit Bandwidth |
5.5kHz to 9kHz (180dB operation) |
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Horizontal Beam Patterns |
Omnidirectional |
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Vertical Beam Patterns |
± 30° |
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Specification - Source and Sequence Modes As a calibrated acoustic test, signal transmitter (source mode) PERS can generate complex acoustic test signals (between 5.5kHz and 9kHz). It is capable of concurrently generating up to 24 tones. An advanced version of the system also allows up to five noise bands (selectable from white, pink or pseudo-random noise) to be generated with the tones. The frequency and source level of each tone (and noise band) may be controlled independently and each selected as CW or pulsed. PERS can also generate LFM or LPM sweeps and complex modulated acoustic transmissions. The advanced system includes a sequence mode allowing the user to program a series of pulse trains giving up to 12,500s of continuous programmed sequenced transmissions, for example 250 uniquely specified pulse trains each with 1000 50ms pulses can be specified. |
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Specification |
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Pulse lengths: |
3ms to 10s or CW |
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Number of pulses: |
Up to 1000 |
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Pulse intervals: |
Up to 60s |
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Variable step levels: |
-10 to +10dB |
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Tones: |
Up to 24 (each with definable source levels & frequencies - CW or pulsed) |
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Sweeps: |
LFM or LPM |
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Noise (advanced system only): |
Either broadband or up to 5 user definable bands |
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Noise types: |
White, Pink or Pseudo-Random |
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Modulated signal (advanced system only): |
AM or FM user definable carrier and modulating signal |
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Specification - Echo Repeat Mode In Echo Repeat mode, PERS can repeat signals (between 5.5kHz and 9kHz) sampled from the receive hydrophone contained in the, hand-deployable, Transducer head. It does this in response to a trigger event, based either on the incoming acoustic signal, an external input, or under operator control. The repeated signal can have a highlight structure imposed upon it to mimic the reflections from a target. The many configurable parameters are controlled via an easily operated Graphical User Interface, running under Microsoft Windows 98. Within this interface, the user can add Doppler, target strength and signal highlights to the echo repeated acoustic signal. Subsequent echo repeated signals could, in addition simulate, a moving target track. |
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Specification |
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Echo frequency: |
Broadband (5.5 to 9kHz) or 3 narrow bands (advanced version) |
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Trigger types: |
Acoustic, TTL pulse or Manual |
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Trigger level and averaging: |
Fully user definable |
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Echo length: |
10ms to 5s |
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Added doppler: |
-40 to +40 knots |
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Added echo strength: |
-30 to +40 knots |
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Echo delay: |
Up to 60s |
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Highlights: |
Up to 5 |
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Highlight strength: |
-30 to +30dB |
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Highlight offset: |
Up to 200ms |
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Moving target track: |
Start range up to 30km, Velocity -40 to +40 knots |
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Tag on transpond: |
User configurable |
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Specification - Transpond Mode In Transpond mode, PERS can transmit a user defined acoustic signal (between 5.5kHz and 9kHz) in response to a trigger event which can be either acoustic, from an external input or under operator control. The transpond signal can be defined as a single pulse, or a ramp of pulses, of a monotone or LFM or LPM sweeps, with selectable frequency and source level. In addition, any selection within the Source Mode can be transponded.
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Specification |
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Frequency range: |
5.5 to 9kHz |
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Trigger types: |
Acoustic, TTL pulse or Manual |
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Trigger level and averaging: |
Fully user definable |
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Transpond types: |
LFM
or LPM sweep, Monotone or Source Mode |
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Sequence Mode |
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Pulse Types: |
Tones, Noise, LFM or LPM Sweeps, modulated signal or pulse trains. |
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Pulse Trains: |
Up to 1000m |
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Pulse Lengths: |
Up to 10s each |
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Mechanical |
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Computer: |
405 x 225 x 205mm, 10kg |
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Power Amplifier: |
440 x 220 x 538mm, 15kg (splash proof) |
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Transducer: |
227 OD x 290mm, 8.3kg |
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Cable Length: |
50m |
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Computer Power Requirement: |
90 to 250V AC auto switching 50/60 Hz |
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PA Power Requirement: |
95 to 130V or 185 to 260VAC auto switching 50/60 Hz. |
