Direction of Arrival Estimation by Moving Antenna for Multipath GNSS

Channel Characterization

Direction of Arrival Estimation by Moving Antenna for Multipath GNSS

Channel Characterization

Mohammad Hatef Keshvadi

Position, Location And Navigation (PLAN) GroupDepartment of Geomatics Engineering

University of Calgary

ENGO699.27 - March 16th, 2010

Mohammad Hatef Keshvadi

Position, Location And Navigation (PLAN) GroupDepartment of Geomatics Engineering

University of Calgary

ENGO699.27 - March 16th, 2010

Direction of Arrival Estimation by Moving Antenna for Multipath GNSS Channel CharacterizationDirection of Arrival Estimation by Moving Antenna for Multipath GNSS Channel Characterization2/13

ContentsContentsContentsContents

• ReviewReview

• Beamscan error analysisBeamscan error analysis

• Implementation of MUSIC DoA method for outdoor dataImplementation of MUSIC DoA method for outdoor data

• Indoor data collection, Upper floor, Mild multipath Indoor data collection, Upper floor, Mild multipath

environmentenvironment

• Indoor data collection, Lower floor, Mild to harsh Indoor data collection, Lower floor, Mild to harsh

multipath environmentmultipath environment

• ConclusionConclusion

• ReviewReview

• Beamscan error analysisBeamscan error analysis

• Implementation of MUSIC DoA method for outdoor dataImplementation of MUSIC DoA method for outdoor data

• Indoor data collection, Upper floor, Mild multipath Indoor data collection, Upper floor, Mild multipath

environmentenvironment

• Indoor data collection, Lower floor, Mild to harsh Indoor data collection, Lower floor, Mild to harsh

multipath environmentmultipath environment

• ConclusionConclusion

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ReviewReviewReviewReview

Previous Tasks:Previous Tasks:• Collecting data on the Collecting data on the

roofroof• Implementation of Implementation of

BeamscanBeamscan• Elevation estimation Elevation estimation

error (deg)error (deg)(for the first revolution):(for the first revolution):

Previous Tasks:Previous Tasks:• Collecting data on the Collecting data on the

roofroof• Implementation of Implementation of

BeamscanBeamscan• Elevation estimation Elevation estimation

error (deg)error (deg)(for the first revolution):(for the first revolution):

PRN 29 PRN 24

El 79.7 67.9

PRN 29 PRN 24

El 4.3 2.6

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Beamscan error AnalysisBeamscan error AnalysisBeamscan error AnalysisBeamscan error AnalysisAnalyzing the error in estimation of elevation angle for Analyzing the error in estimation of elevation angle for

various revolutions of the antennavarious revolutions of the antenna

(Ref. of measurement: Navigation data from Novatel’s DTU software)(Ref. of measurement: Navigation data from Novatel’s DTU software)

Analyzing the error in estimation of elevation angle for Analyzing the error in estimation of elevation angle for

various revolutions of the antennavarious revolutions of the antenna

(Ref. of measurement: Navigation data from Novatel’s DTU software)(Ref. of measurement: Navigation data from Novatel’s DTU software)

PRN 29 PRN 24

Mean 3.6 2.4

Variance 0.06 0.08

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 162

2.5

3

3.5

4

4.5

Revolution No.

Err

or

(de

g)

Beamscan Elevation Estimation Error

PRN-29

PRN-24

Probably due to time offset between the data collection time and capturing the satellite’s position time.

Search Space Steps:

0.01 rad = 0.57 deg

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Implementation of MUSIC: outdoor dataImplementation of MUSIC: outdoor dataImplementation of MUSIC: outdoor dataImplementation of MUSIC: outdoor data

PRN 29 PRN 24

El 79.7 67.9

MUSIC:

Scanning the field of view to find spots where noise subspace is orthogonal to the signal subspace.

Higher resolution comparing to Beamscan

The same error pattern as Beamscan method

Data collection environment: CCIT rooftop (No Multipath)

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Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)

Data collected in a typical North American, wooden frame residential structure.

This location is prone to mild to harsh multipath and fading

Data collection specifications:

Date: 5 Feb. 2010, 11:00am until 12:00pm

Revolution Speed:4 revs/min

System Architecture:

Outdoor Ref. Ant. And Indoor Rotating Ant.

Coherent Int. Time: 200msec

Radius of Rotation: 51cm

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Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)

El (deg)

PRN-18 56.07

PRN-24 61.99

PRN-29 30.42

More than 1 peak is observed in indoor environment

The height of the secondary peaks is always less than 1

The peak’s location is not constant with time (unlike outdoor conditions)

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Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)

Satellite’s actual Elevation: 62o

Variations of Signal’s source with time:

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Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)Indoor data collection (Upper floor)Error AnalysisError AnalysisError AnalysisError Analysis

0 2 4 6 8 10 12-8

-6

-4

-2

0

2

4

Number of Revolutions

Ele

vatio

n A

ng

le E

stim

atio

n E

rro

r (d

eg

)

Error in Estimating Elevation AngleMild Multipath Environment (Upper Floor)

BeamscanMUSIC

PRN - 29

PRN - 29Beamscan MUSIC

mean 2.27 1.03

Variance 0.37 10.96

Max 3.38 3.95

Min 1.09 -6.93

Time interval between each revolution: 15s

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Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)The same building as previous scenario.

The test apparatus moved from main floor to lower floor to investigate the effects of higher levels of Multipath and Fading

Data collection specifications:

Date: 5 Feb. 2010, 13:00pm until

14:30pm

Revolution Speed:4 revs/min

System Architecture:

Outdoor Ref. Ant. And Indoor

Rotating Ant.

Coherent Int. Time: 200msec

Radius of Rotation: 36cm

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Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)

El Az

PRN-18 77.01 68.82

PRN-24 20.98 119.45

The number of observed peaks increase

Peaks vary more significantly in power by time

The peak’s location has temporal variations

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Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)Error AnalysisError AnalysisError AnalysisError Analysis

1 2 3 4-15

-10

-5

0

5

10

Revolution Number

Ele

vati

on

Est

imat

ion

Err

or

(deg

)

Error in estimation of Elevation AngleMild to Harsh Multipath Environment

PRN 18 BeamscanPRN 18 MUSICPRN 24 BeamscanPRN 24 MUSIC

Beamscan

PRN18 PRN24

Mean -13.56 5.95

Variance 0.084 9.81

MUSIC

PRN18 PRN24

Mean -13.42 5.66

Variance 0.220 15.04

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ConclusionsConclusionsConclusionsConclusions•For mild multipath environments, the error in For mild multipath environments, the error in estimation of DoA reaches to several (6~8) estimation of DoA reaches to several (6~8) degrees.degrees.By increasing the level of multipath, this error By increasing the level of multipath, this error increases while introducing more and relatively increases while introducing more and relatively stronger sources of signal.stronger sources of signal.

Future worksFuture works1- Implementing FFT based DoA methods1- Implementing FFT based DoA methods2- Implementing Beamforming methods2- Implementing Beamforming methods3- Applying the above derived algorithms on a set 3- Applying the above derived algorithms on a set of data collected in a harsh multipath of data collected in a harsh multipath environmentenvironment

•For mild multipath environments, the error in For mild multipath environments, the error in estimation of DoA reaches to several (6~8) estimation of DoA reaches to several (6~8) degrees.degrees.By increasing the level of multipath, this error By increasing the level of multipath, this error increases while introducing more and relatively increases while introducing more and relatively stronger sources of signal.stronger sources of signal.

Future worksFuture works1- Implementing FFT based DoA methods1- Implementing FFT based DoA methods2- Implementing Beamforming methods2- Implementing Beamforming methods3- Applying the above derived algorithms on a set 3- Applying the above derived algorithms on a set of data collected in a harsh multipath of data collected in a harsh multipath environmentenvironment

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Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)

Variations of Signal’s source with time:

PRN 18 – High elevation

Satellite’s actual Elevation: 77o

APPENDIX

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Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)Indoor data collection (Lower floor)

Variations of Signal’s source with time:

PRN 24 – Low elevation Low C/N0 and antenna pattern effects

Satellite’s actual Elevation: 21o

APPENDIX