Multi-Receiver Vector TrackingYuting Ng and Grace Xingxin Gao

please feel free to view the .pptx version for the speaker notes

Cutting-Edge Applications

Sampling Device

NetworkSync.

time

voltage/ current

synchronized phasor measurements

PMU

interference mitigation

SAR-GNSSProcessing

remotesensing

UAV formation

flight

1

State-of-the-Art Techniques

Multiple antennas

Multiple receivers

Signal tracking

beamstearing

increased availability

PPP

DGPS

EKF IMU

clock

VDLL

VFLL

External aiding

increased robustness

RTK

2

State-of-the-Art Techniques

Multiple antennas

Multiple receivers

Signal tracking

External aiding

beamstearing

increased availability

PPP

DGPS

EKF IMU

clock

VDLL

VFLL

increased robustness

RTK

2

State-of-the-Art Techniques

Multiple receivers

Multiple antennas

Signal tracking

External aiding

beamstearing

increased availability

PPP

DGPS

EKF IMU

clock

VDLL

VFLL

Cooperative NavigationJoint Signal Tracking

increased robustness

RTK

2

Joint tracking of multiple GNSS receivers for increased accuracy, robustness and reliability

Multi-Receiver Vector Tracking

3

•Motivation | Coop Nav, Joint Signal Tracking

•Our Approach | Multi-Receiver Vector

Tracking

•Implementation | Hardware, Python SDR

•Experimental Validation

•Summary

Outline

Receiver Network

Channel 1

Channel N

...

...

...

Receiver

...

Receiver

N ChannelsM Receivers4 Unknowns

Scheme Scalar SRVT MRVT

Entities N x M Channels M Receivers 1 Network

Unknowns N x M x 4 M x 8 1 x 14

M Receivers8 Unknowns

1 Network14 Unknowns

incoming raw signal

MRVT Receiver Architecture

4

Comparison with other GNSS Processing Implementations

Single-Receiver Vector Tracking (SRVT) Multi-Receiver Vector Tracking (MRVT)

Antenna array Differential GPS (DGPS)

GNSS Receiver

GNSS Receiver

GNSS Receiver

Nav Filter

measurements/ coordinates

5

MRVT Block Diagram

6

MRVT Block Diagram

6

Single Receiver Vector Tracking Loop

EKF-based Filter

Vector Delay Lock Loop - James J. Spilker, Jr. Global Positioning System-Theory and Applications, Volumes I, II. AIAA, Washington, DC., 1996.7

Single Receiver PIA Vector Tracking

State Representation Process Noise Cov.

8

Single Receiver PIA Vector Tracking

State Representation Process Noise Covariance Matrix

σ2σ2

9

MRVT Block Diagram

10

MRVT Loop

11

MRVT Variations

MRPIAVT• Enforce timing constraints

→clock bias differ by constant→clock drift same

MRVTEnforce baseline, attitude

and velocity constraintsEnforce timing constraints

12

Correlator

Code and Carrier Discriminators

Measurement Update

Code and CarrierNCO

Channel

incoming GPS signal

a prioriinformation

TimeUpdate

LOS Projections

EKF

navigationsolution

Multi-Receiver Vector Tracking

MRVT Filter

Receiver

ReceiverNetwork

13

•Motivation | Coop Nav, Joint Signal Tracking

•Our Approach | Multi-Receiver Vector

Tracking

•Implementation | Hardware, Python SDR

•Experimental Validation

•Summary

Outline

Overall Implementation

Software (Python SDR)

GNSS antennas ADCs

Receiver

Network

4.60m

Hardware

14

Python SDR : Research Platform

• Share information effectively• SDR (Software Defined Radio)

• OOP (Object-Oriented Programming)

15

Python SDR : Research Platform

16

Python SDR : Teaching Platform

17

Python SDR : Teaching Platform

17

•Motivation | Coop Nav, Joint Signal Tracking

•Our Approach | Multi-Receiver Vector

Tracking

•Implementation | Hardware, Python SDR

•Experimental Validation

•Summary

Outline

MRVT Positioning Results

SRVT MRVT

18

zoomed inSRVT

zoomed inMRVT

MRVT Positioning Results

SRVT MRVT

18

zoomed inSRVT

zoomed inMRVT

MRVT Results: Reliable Altitudes

19

MR

VT

Res

ults

: Acc

urat

e B

asel

ines 19

MR

VT

Res

ults

: Les

s N

oisy

Spe

eds 19

Res

ults

with

Bui

ldin

gs+A

ccel

erat

ions

SRVT

MRV

T

20

Res

ults

with

Bui

ldin

gs+A

ccel

erat

ions

zoom

ed in

zoom

ed in

20

SRVT

MRV

T

MR

PIA

VT

Res

ults

:Im

prov

ed T

imin

g A

ccur

acy

SRVT

MR

PIAV

T

21

MR

PIA

VT

Res

ults

:Im

prov

ed T

imin

g A

ccur

acy

SRVT

MR

PIAV

T

21

MR

PIA

VT:

Res

ista

nt to

Jam

min

gA

dded

noi

se o

f diff

eren

t lev

els Clo

ck d

rift c

ompa

rison

ac

ross

diff

eren

t noi

se p

ower

Clo

ck b

ias

com

paris

on

acro

ss d

iffer

ent n

oise

pow

er

22

MR

PIA

VT:

Rob

ust t

o M

eaco

ning

cloc

k bi

ascl

ock

drift

||sta

te e

rror c

ov||

cloc

k bi

ascl

ock

drift

||sta

te e

rror c

ov||

wea

k m

eaco

ning

(1:1

pow

er ra

tio)

stro

ng m

eaco

ning

(100

:1 p

ower

ratio

)

robu

st to

at

tack

atta

ckde

tect

ed

23

MR

PIA

VT:

Det

ects

Dat

a S

poof

ing

cloc

k bi

ascl

ock

drift

||sta

te e

rror c

ov||

sate

llite

clo

ck b

iase

s sh

ifted

by

4s

atta

ckde

tect

ed

Atta

cked

af 0

in

Sub

fram

e 1

of

Eph

emer

ides

24

•Mot

ivatio

n | C

oop

Nav

, Joi

nt S

igna

l Tra

ckin

g

•Our

App

roac

h | M

ulti-

Rec

eive

r V

ecto

r

Trac

king

•Impl

emen

tatio

n | H

ardw

are,

Pyt

hon

SD

R

•Exp

erim

enta

l Val

idat

ion

•Sum

mar

y

Out

line

•Pr

opos

ed M

ulti-

Rec

eive

r Ve

ctor

Tra

ckin

g (M

RVT

)–

Coo

pera

tive

navi

gatio

n–

Join

t sig

nal t

rack

ing

•D

esig

ned

MR

VT A

rchi

tect

ure

Impl

emen

ted

in P

ytho

n SD

R

•C

ondu

cted

MR

VT E

xper

imen

ts

•Va

lidat

ed P

erfo

rman

ce Im

prov

emen

ts

–M

RVT

: D

emon

stra

ted

incr

ease

d ac

cura

cy in

hor

izon

tal

head

ing,

alti

tude

s, b

asel

ines

, spe

eds,

tim

ing

–M

RPI

AVT

: Dem

onst

rate

d im

prov

ed ti

min

g ac

cura

cy

and

prec

isio

n, ro

bust

ness

aga

inst

tim

ing

atta

cks

Sum

mar

y

25

Than

k yo

u!

From

all

of u

s @

UIU

C