Evaluation of Position Sensing Techniques for an Unmanned Aerial Vehicle.

95 Pages·2006·0.98 MB·English

by  Martin Alkeryd

Institutionen för systemteknik
Department of Electrical Engineering
Examensarbete
Evaluation of Position Sensing Techniques for an
Unmanned Aerial Vehicle.
Examensarbete utfört i Reglerteknik
vid Tekniska högskolani Linköping
av
Martin Alkeryd
LITH-ISY-EX--06/3790--SE
Linköping 2006
Department of Electrical Engineering Linköpings tekniska högskola
Linköpings universitet Linköpings universitet
SE-581 83 Linköping, Sweden 581 83 Linköping

Evaluation of Position Sensing Techniques for an
Unmanned Aerial Vehicle.
Examensarbete utfört i Reglerteknik
vid Tekniska högskolan i Linköping
av
Martin Alkeryd
LITH-ISY-EX--06/3790--SE
Handledare: Johanna Wallén, MSc
ISY, Linköpingstekniska högskola
Jan-Erik Strömberg, PhD
DST Control AB
Examinator: Prof. Svante Gunnarsson
ISY, Linköpingstekniska högskola
Linköping, 31 March, 2006

Avdelning,Institution Datum
Division,Department Date
DivisionofAutomaticControl
DepartmentofElectricalEngineering
2006-03-31
Linköpingsuniversitet
S-58183Linköping,Sweden
Språk Rapporttyp ISBN
Language Reportcategory
—
(cid:3)Svenska/Swedish (cid:3)Licentiatavhandling ISRN
(cid:3)⊠Engelska/English (cid:3)⊠Examensarbete LITH-ISY-EX--06/3790--SE
(cid:3)C-uppsats
Serietitel och serienummer ISSN
(cid:3)D-uppsats Titleofseries,numbering
—
(cid:3) (cid:3)Övrigrapport
(cid:3)
URL förelektronisk version
http://www.ep.liu.se
Titel Utvärderingav positionsbestämningsteknikerför en obemannadflygandefarkost
Title (UAV).
EvaluationofPositionSensingTechniquesforanUnmannedAerialVehicle.
Författare MartinAlkeryd
Author
Sammanfattning
Abstract
TheuseofUnmannedAerialVehicles(UAVs)hasrapidlyincreasedoverthelast
years. This has been possible mainly due to the increased computing power of
microcontrollersandcomputers. AnUAVcanbeusedinbothcivilianandmilit-
ary areas, for examplesurveillanceand intelligence. The UAV concernedin this
master’s thesis is a prototype and is currently being developed at DST Control
ABinLinköping.
WiththeuseofUAVs,theneedforapositioningandnavigationsystemarises.
Inertialsensorscanoftengiveagoodpositionestimation,however,theyneedcon-
tinuouscalibrationduetoerrorbuild-upanddriftingyros. Anexternalreference
isneededtocorrectforthisdriftandothererrors. Thepositioningsysteminvest-
igatedinthismaster’sthesisissupposedtoworkinanareadefinedbyaninverted
conewiththeheightof25mandadiameterof10m.
A comparison of different techniques suitable for position sensing has been
performed. These techniques include the following: a radio method based on
theInstrumentLandingSystem(ILS),anopticalmethodusingaPositionSensing
Detector(PSD),anopticalmethodusingtheIndoorGPSsystem,adistancemeas-
urementmethodwithultrasoundandalsoadiscussionoftheGlobalPositioning
System(GPS).
AnevaluationsystemhasbeenbuiltusingthePSDsensorandtestshavebeen
performedtoevaluateitspossibilitiesforpositioning. Anaccuracyintheorderof
a few millimetreshave been achieved in position estimation with the evaluation
system.
Nyckelord
Keywords UAV,UnmannedAerialVehicle,positioning,PSD,trilateration,GPS,PSD,Pos-
itionSensingDetector,ILS

Abstract
The use of Unmanned Aerial Vehicles (UAVs) has rapidly increased over the last
years. This has been possible mainly due to the increased computing power of
microcontrollers and computers. An UAV can be used in both civilian and milit-
ary areas, for example surveillance and intelligence. The UAV concerned in this
master’s thesis is a prototype and is currently being developed at DST Control
AB in Linköping.
WiththeuseofUAVs,the needforapositioningandnavigationsystemarises.
Inertialsensorscanoftengiveagoodpositionestimation,however,theyneedcon-
tinuous calibrationdue to errorbuild-up anddrift in gyros. An externalreference
is needed to correctfor this drift and other errors. The positioning systeminvest-
igatedinthismaster’sthesisissupposedtoworkinanareadefinedbyaninverted
cone with the height of 25m and a diameter of 10m.
A comparison of different techniques suitable for position sensing has been
performed. These techniques include the following: a radio method based on
theInstrumentLandingSystem(ILS),anopticalmethodusingaPositionSensing
Detector(PSD),anopticalmethodusingtheIndoorGPSsystem,adistancemeas-
urement method with ultrasound and also a discussion of the Global Positioning
System (GPS).
Anevaluationsystemhasbeenbuiltusingthe PSDsensorandtestshavebeen
performedto evaluate its possibilities for positioning. An accuracyinthe order of
a few millimetres have been achieved in position estimation with the evaluation
system.
v

Acknowledgements
During the work of this master’s thesis many people have been very helpful. To
beginwithIwouldlikethankmysupervisorJan-ErikStrömbergandthepeopleat
DST Control. Thanks for aninteresting master’s thesis projectandgoodadvices.
Thanks also to the neighbour companies CybAero AB and Impact Coatings AB
for the nice atmosphere.
A big thanks also to my examiner Svante Gunnarsson and university supervisor
JohannaWallén,forquickanswerstomyquestionsandvaluablecommentsonthe
report.
Thanks to my opponent Mattias Eriksson for the comments on my work and
my report.
I have received valuable advice regarding electronics and microcontrollers from
Erik Alfredsson.
Thanks also to my father, Gunnar Alkeryd, for good ideas and for providing the
slide projector.
Anders Lundgren at SiTek AB has given many good advices regarding PSDs.
Park Air Systems has been helpful with discussions of ILS and positioning sys-
tems.
Martin Alkeryd
Linköping, spring 2006
ThisdocumentwaspreparedusingLATEXonanApplePowerBookG4. Thefigures
were produced using Dia (from http://www.gnome.org/projects/dia)and the
plots were produced using Matlab (from Math Works, Inc.).
vii