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Chapter 4: Sonar Technology, AMIRUL HAKIMI BIN JAMIL A17SC0284 - Coggle…
Chapter 4: Sonar Technology
Sonar
device using in detecting underwater objects using sound wave.
sound pulse generated, sent to underwater using transmitter, than reflect back by u/w objects and received by receiver.
Distance = Speed x Time
Type
Active: used transmitter & receiver
Monostatic: Tr and Rec same place
Bistatic: Tr and Rec separated by distance
Multistatic: more Tr/Rec used // spatially separated
Passive: listens w/o transmitting
have large sonic database
wide techniques in identifying source of detected sound
sonar operator classify signal using comp. (identify ship and action classes.
Application
find actual depth of sea
find lost ships & subs
ocean surveillance systems
navy used detecting enemy's subs
underwater security
Limitation
adverse effects in marine animals
whales in pain & often fatal decompression sickness
generate lots of noises
high intensity create temporary shift in hearing threshold of fishes
FINGER IO
easier to interact with smart gadgets
simply scribbling on any nearby surface
active sonar using microphone & speaker (a device)
track fine-grained movement in within 8 mm
2D finger motion: 2 mic, 3D finger motion: 3 mic
track subtle finger motion around device even device in pocket
Currently F IO
min. diff. between drawings & F IO: sphones-8mm, swatches-12mm
F IO prototypes apps well equipped with 2 mics in sphones and swatches.
easy way to type using this technque
does not require special finger instrumentation sensors and hardware
easier interacting with device that have small screens
Advantages F IO
used to identify object effectively (underwater(
use various water based activities as sonar not attenuate as much as light and radar waves in seawater.
very accurate system
too expensive
Limitations F IO
cause refraction of acoustic energy
wave emitted by sonar threaten marine animals
sonar system generates lots of noises
sonar's acoustic waves affected by sound velocity varieties over depth
AMIRUL HAKIMI BIN JAMIL A17SC0284