# 0.1 Behind the scenes: algorithms at work

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In this module is a description of multilateration, the technique used to pinpoint position.

## Behind the scenes algorithms:

Because we know only the time difference between each microphone’s recognition of the sound, not the initial time of the sound itself, we decided to use multilateration as the primary algorithm. Multilateration uses the time difference of arrival to calculate a distance from the receivers. Plotting with a radius of this distance yields a hyperbolic arc that gives possible locations for the sound. The intersection of multiple arcs found by using multiple sensors gives the position of the origin of the sound.

In more detail, the microphones pick up the sound at different times which Matlab then cross correlates to get the time difference of arrival between any two sensors. This time difference of arrival is then used with the speed of the sound to create a series of linear equations that when solved, will give the direction and position of the sound’s origin.

With a sound emitter (Es) at some unknown position (x,y), we create a coordinate system around the known positions of the sensors, with the position of one sensor defined as the origin (S0). Using this sensor as the origin simplifies the distance from this sensor to Es. The distance from the sensor at the origin to the emitter can be written as

d0=S0 - Es= x2+ y2

The distance d0 is the speed of sound multiplied by the transit time (T0). However, since we do not know T0, we use the time difference of arrival between S0 and any other sensor, Sm.

vτm=vTm- vT0

vτm= dm- d0

Next, we used the cross correlation function to measure the time shift between the recorded waveforms, which is τm. Some manipulation of the above equations gives a set of linear equations of Es.

0=xAm+yBm+C m

where Am, Bm, and Cm are constants representing the distances from the chosen sensor Sm and Es. Because S0 is used in each equation, S0 cannot be used to generate an equation for the set.

As an algorithm, multilateration requires very little input: the times at which each microphone recognizes the sound, the fixed distance between the microphones, and the speed of sound. As a result, it was easier to implement multilateration over more conventional triangulation methods in which the angle and the distances between the microphones and the origin of sound are needed.

where we get a research paper on Nano chemistry....?
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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