├── .gitignore
├── LICENSE
├── README.md
└── main.py


/.gitignore:
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 1 | *.py[cod]
 2 | 
 3 | # C extensions
 4 | *.so
 5 | 
 6 | # Packages
 7 | *.egg
 8 | *.egg-info
 9 | dist
10 | build
11 | eggs
12 | parts
13 | bin
14 | var
15 | sdist
16 | develop-eggs
17 | .installed.cfg
18 | lib
19 | lib64
20 | __pycache__
21 | 
22 | # Installer logs
23 | pip-log.txt
24 | 
25 | # Unit test / coverage reports
26 | .coverage
27 | .tox
28 | nosetests.xml
29 | 
30 | # Translations
31 | *.mo
32 | 
33 | # Mr Developer
34 | .mr.developer.cfg
35 | .project
36 | .pydevproject
37 | 
38 | octave-workspace
39 | 


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/LICENSE:
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 1 | The MIT License (MIT)
 2 | 
 3 | Copyright (c) 2014 Paul Hayes
 4 | 
 5 | Permission is hereby granted, free of charge, to any person obtaining a copy of
 6 | this software and associated documentation files (the "Software"), to deal in
 7 | the Software without restriction, including without limitation the rights to
 8 | use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 9 | the Software, and to permit persons to whom the Software is furnished to do so,
10 | subject to the following conditions:
11 | 
12 | The above copyright notice and this permission notice shall be included in all
13 | copies or substantial portions of the Software.
14 | 
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
17 | FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
18 | COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
19 | IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
20 | CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 | 


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/README.md:
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1 | Multilateration Example
2 | ======================
3 | 
4 | Python rewrite of multilateration technique by André Andersen in his [blog post](http://blog.andersen.im/2012/07/signal-emitter-positioning-using-multilateration).


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/main.py:
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 1 | ###########################
 2 | #
 3 | # Python rewrite of multilateration technique by André Andersen in his [blog post](http://blog.andersen.im/2012/07/signal-emitter-positioning-using-multilateration).
 4 | #
 5 | ############################
 6 | 
 7 | from numpy import *
 8 | from numpy.linalg import *
 9 | import json
10 | #speed of sound in medium
11 | v = 3450
12 | numOfDimensions = 3
13 | nSensors = 5
14 | region = 3
15 | sensorRegion = 2
16 | 
17 | #choose a random sensor location
18 | emitterLocation = region * ( random.random_sample(numOfDimensions) - 0.5 )
19 | sensorLocations = [ sensorRegion * ( random.random_sample(numOfDimensions)-0.5 ) for n in range(nSensors) ]
20 | p = matrix( sensorLocations ).T
21 | 
22 | #Time from emitter to each sensor
23 | sensorTimes = [ sqrt( dot(location-emitterLocation,location-emitterLocation) ) / v for location in sensorLocations ]
24 | 
25 | c = argmin(sensorTimes)
26 | cTime = sensorTimes[c]
27 | 
28 | #sensors delta time relative to sensor c
29 | t = sensorDeltaTimes = [ sensorTime - cTime for sensorTime in sensorTimes ]
30 | 
31 | ijs = range(nSensors)
32 | del ijs[c]
33 | 
34 | A = zeros([nSensors-1,numOfDimensions])
35 | b = zeros([nSensors-1,1])
36 | iRow = 0
37 | rankA = 0
38 | 
39 | for i in ijs:
40 | 	for j in ijs:
41 | 		A[iRow,:] = 2*( v*(t[j])*(p[:,i]-p[:,c]).T - v*(t[i])*(p[:,j]-p[:,c]).T )
42 | 		b[iRow] = v*(t[i])*(v*v*(t[j])**2-p[:,j].T*p[:,j]) + \
43 | 		(v*(t[i])-v*(t[j]))*p[:,c].T*p[:,c] + \
44 | 		v*(t[j])*(p[:,i].T*p[:,i]-v*v*(t[i])**2)
45 | 		rankA = matrix_rank(A)
46 | 		if rankA >= numOfDimensions :
47 | 			break
48 | 		iRow += 1
49 | 	if rankA >= numOfDimensions:
50 | 		break
51 | 
52 | calculatedLocation = asarray( lstsq(A,b)[0] )[:,0]
53 | 
54 | print "Emitter location: %s " % emitterLocation
55 | print "Calculated position of emitter: %s " % calculatedLocation
56 | 


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