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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.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
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Source:  OpenStax, The boomerang project: a recreation. OpenStax CNX. Dec 19, 2011 Download for free at http://cnx.org/content/col11394/1.1
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