PROFESSIONAL AUDIO LABORATORIES
Park Ridge, NJ 07656
PINGER LOCATION USING FORENSIC ENHANCEMENT TECHNIQUES
Locating an aircraft signal pinger in ocean water can be a daunting task. The ocean has many sounds over a broad spectrum making for a difficult environment to be searching in. The motion and flow of the water adds "noise", or ambient sounds to that emitted by the motions of the sea creatures, as well as those sounds that are used for communication within each species.
To demonstrate techniques that can be used to identify the faint sounds of the pinger in this very noisy environment I have prepared a simulation of a received signal, of a pinger sound (in this case I used 1,000Hz) in random noise.
The original simulated pinger sound is a clean 1 kHz (1,000 cycles per second) sound.
Plot 1 shows a received signal in the presence of noise. It is essentially buried in the ocean sounds.
PLOT 1 - Simulated Pinger Sound Imbedded in Ocean Noise
After some enhancement with a judicious choice of forensic enhancement tools, we have:
PLOT 2 - Simulated Pinger Sound in Ocean Noise After Initial Filtering
Note the discrete one- second repetition rate that is recognized as a possible pinger signal
After additional enhancement we have:
PLOT 3 - Simulated Pinger Sound in Ocean Noise After Additional Filtering
We now have a recognizable waveform that can be evaluated in detail.
Various techniques can be utilized to take advantage of the known characteristics of the pinger output, as compared with the relatively random ocean ambient noise.
For more information explore the entire website.
I can be reached at (201) 664-8333 or by email at info@proaudiolabs.com and on Twitter @ProAudioLabs
Paul Ginsberg, President
Professional Audio Laboratories, Inc.