name: chengming jin supervisor: allison kealy · 2017. 1. 13. · next-generation train control...
TRANSCRIPT
Name: Chengming Jin Supervisor: Allison Kealy
GNSS-based Positioning Scheme & Application in Safety-critical Systems
of Rail Transport
CONTENT
Introduction 1
Challenges 2
Solutions 3
Introduction
How Modern Railway Signal Works?
1
Introduction
Signalling System: Track Circuit
2
Introduction
History of Signalling Systems
Diversity of European ATP systems ETRMS/ETCS Cockpit 3
Driver
Token
Signalman
Introduction
Train Control Systems: Positioning Scheme
one engine in steam
A token being offered by a signalman on the Keighley and Worth Valley Railway (from Wikipedia) 4
Calibration
speed, location
speed, location
Introduction
Train Control Systems: Positioning Scheme
Accumulated error
5
difficult to maintain
Expensive
2.5 km
Introduction
Train control systems: Balise
More in station
6
Introduction
Signalling System: Fixed Block & Moving Block
*THE DEVELOPMENT AND PRINCIPLES OF UK SIGNALLING 7
Mainstream Signalling System
Signalling System in the Future
A B C D E
Full radio-based train spacing
Moving Block
Trains find their position themselves
Introduction
Next-Generation Train Control System
Ability to determine train integrity on board No track circuit
No or less balise
8
Introduction
with high accuracy in all weather conditions anywhere on or near the Earth Cost-efficient available 24/7/365
GNSS
Location info. Time info. Short messages(BDS)
9
Introduction
GNSS-based train control systems
WAAS
GPS WAASGALILEO EGNOS
GLONASS SDCM
GAGAN
MSAS QZSS
EC and European Railway Agency (ERA) launched many projects to promote the progress of GNSS-based railway applications
GPS-based PTC (Positive Train Control) had been equipped in
the US and China (Qinghai-Tibet Line)
ATLAS 400, an European GPS-based train control system
Non-safety applications
Europe GNSS-based railway applications projects
2005
2010
2012 3InSat SATLOC
GRail
GRailⅡ
2004
2001InteGRail
GEORAIL
Gaderos
RUNE
ECORAIL Locoprol
2014 Shift2Rail
BDS
GNSS is a worldwide, cost-efficient approach to locate the target, which makes GNSS-based positioning become one of the most promising positioning solutions for the next-generation train control system.
10
CONTENT
Introduction 1
Challenges 2
Solutions 3
Policy issue
Challenges
GNSS was refused by railway:
ETCS (European Train Control System) 、 CTCS (Chinese Train Control System) have been standardized in the last two decades.
Balise and STM (Specific Transmission Module) are necessary in ETCS-1,2.
ERTMS/ETCS reference architecture* *SUBSET-026 ERTMS/ETCS System Requirements Specification issue:3.0.0
11
Accuracy
Challenges
GNSS was refused by railway:
Accuracy of distances measured on-board:
Accuracy of distinguishing parallel tracks: 1.5m
ERTMS/ETCS reference architecture* *SUBSET-026 ERTMS/ETCS System Requirements Specification issue:3.0.0
3-5m
Masked sky & multipath
34%
Masked sky & multipath
(5 5% )m S± +
12
RAMS
Challenges
GNSS was refused by railway:
Railway applications must meet the requirements for Reliability, Availability, Maintainability, and Safety
GNSS performance parameters, which are derived from aviation, are SIS Availability, Integrity, Continuity
Safety: According to CCS TSI 2012/88/EU, for the hazard `exceeding speed and/or distance limits advised to ERTMS/ETCS' the tolerable rate (THR) is 10-9/h for random failure, for on-board ERTMS/ETCS and for track-side, and positioning unit is just one of many subsystems.
Relation between GNSS and Railway Signalling QoS Properties*
*Debiao Lu, “GNSS for Train Localisation Performance Evaluation and Verification”, Dissertation, 2014.
<10-9
?
There is a wall!!
13
CONTENT
Introduction 1
Challenges 2
Solutions 3
Solutions
Solutions:
High Accuracy
High Availability
High Safety
Pseudorange-based GNSS
Carrier-phase-based GNSS
SPS
DGNSS
RTK
PPP
Potentially
SPS: Standard Positioning Service DGNSS: Differential GNSS RTK: Real Time Kinematic PPP: Precise Point Positioning 14
Solutions
Solutions: Why PPP?
* M.D. Laínez Samper et al, Multisystem real time precise-point-positioning, Coordinates, Volume VII, Issue 2, February 2011
In comparison with DGNSS, PPP has higher accuracy(centimetre to decimetre level*) Compared with RTK, PPP requires fewer reference stations globally distributed. PPP
gives a highly redundant and robust position solution
i i i
j j j
ϕ ρ ε
ϕ ρ ε
= +
− = − −
kk kϕ ερ= +
Station movements that result from geophysical phenomena such as tectonic plate motion, Earth tides and ocean loading enter the PPP solution in full, as do observation errors resulting from the troposphere and ionosphere. Relevant satellite specific errors are satellite clocks, satellite antenna phase center offset, group delay differential, relativity and satellite antenna phase wind-up error. Receiver specific errors are receiver antenna phase center offset and receiver antenna phase wind-up.
Differential solutions
PPP solutions
15
Solutions
Solutions: PPP-based multi-sensor fusion
IMU
PPP
ODO EKF
Navigation Processor
bibfbibω
−nOv
,a gb b ,neb bv pδ δb
nbδψ
,n nI Ip v
Integrity Monitoring
+
+
Corrected Position,Velocity, Attitude
Integrity Information
,n nG Gp v
Kδ
16 IMU: Inertial Measurement Unit ODO: odometer EKF: Extended Kalman Filter
Solutions
Scenarios
16
GNSS/PPP IMU ODO Scenario 1 available not converged available available Scenario 2 available converged available available
Scenario 3 unavailable available available
Solutions
On-site test
Trajectory of On-site Test Position Error
17
-4.1299 -4.1298 -4.1297 -4.1296 -4.1295 -4.1294 -4.1293 -4.1292 -4.1291
ECEF x axis (unit:m) 10 6
2.8936
2.8938
2.894
2.8942
2.8944
2.8946
2.8948
2.895
2.8952
2.8954
2.8956
EC
EF
y ax
is (u
nit:m
)
10 6GNSS/INS Kalman Filter compares with GNSS position
Kalman Filter Solution
GNSS Position Info.
Solutions
Simulation test
SPIRENT Simulator Navigation Trajectory
17
-2.1723 -2.1722 -2.1721 -2.172 -2.1719
ECEF x axis (unit:m) 10 6
4.38785
4.3879
4.38795
4.388
4.38805
4.3881
4.38815
4.3882
EC
EF
y ax
is (u
nit:m
)
10 6 INS Navi. Solution Compares with Real Trajectory
INS Navi. Solution
Real Trajectory
Solutions
Solutions: PPP-based multi-sensor fusion
INS/ODO Kalman Filter Navigation Error INS Navigation Error
*GNSS position error ~ N(0,1); GNSS velocity error ~ N(0,0.01); ODO velocity error ~ N(0,0.01)
0 1000 2000 3000 4000 5000 6000
Num of Navigation Solution
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
INS
/OD
O N
avig
taio
n er
ror(
unit:
m)
INS/ODO Kalman Filter Position Error
North Error
East Error
Down Error
0 1000 2000 3000 4000 5000 6000
Num of Navigation Solution
-10
-5
0
5
10
15
Nav
igat
ion
Erro
r(uni
t:m)
INS Navigation Error
North error
East error
Down error
17
Solutions
Solutions: PPP-based multi-sensor fusion
0 1000 2000 3000 4000 5000 6000
Num of Navigation Solution (Sample frequency: 100 Hz)
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
GN
SS
/INS
Kal
man
Filt
er N
avig
atio
n E
rror(u
nit:m
)
GNSS/INS Kalman Filter Position Error
North error
East error
Down error
0 1000 2000 3000 4000 5000 6000
Num of Navigation Solution (Sample frequency: 100 Hz)
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
GN
SS/IN
S/O
DO
Nav
igat
ion
Erro
r(uni
t:m)
GNSS/INS/ODO Kalman Filter position error
North error
East error
Down error
GNSS/INS Kalman Filter Navigation Error GNSS/INS/ODO Kalman Filter Navigation Error
*GNSS position error ~ N(0,1); GNSS velocity error ~ N(0,0.01); ODO velocity error ~ N(0,0.01) 18
Solutions
Quality Control: Detection, Identification and Adaptation(DIA)
*Quality control and integrity, Delft school
Based on consistency check of innovations 1
k
Tk v k
kk
v Q vt
m
−
=
19
Solutions
Quality Control: Detection, Identification and Adaptation(DIA)
Bias (unit: degree) Detected Missed Detection Success Rate
0 1000 20 98.04%
0.0000001 77 943 7.54%
0.000001 1000 20 98.04%
0.1 1000 20 98.04%
0.5 1000 20 98.04%
10 1020 0 100%
Bias (unit: m/s) Detected Missed Detection Success Rate
0 1000 20 98.04%
0.1 134 886 13.13%
0.5 1000 20 98.04%
1 1020 0 100%
20
Solutions
Threshold
20
0 5 10 15 20 25 30 35 40 45 500
0.02
0.04
0.06
0.08
0.1
0.12
Chi-squareNoncentral Chi-squareThreshold
THR <= 10-9/h
Solutions
Further Research
DIA global test
PPP integrity monitoring scheme
Track maps aided
21
Thank You
Lhasa