GNSS_System(Heo Moon Beom) remplacement des naviagtion calassique .ppt

GNSS System
Moon Beom Heo, Ph.D
Head of Satellite Navigation Dept.
Space Application & Future Technology Center
Korea Aerospace Research Institute

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Contents
 GNSS Basics
 Error Sources
 ABAS
 GBAS
 SBAS
 GRAS

3
Navigation
 Ships/Aircrafts used Light, Sound, Radio Wave to
estimate its position.

4
Uplink Station
보강시스템
PNT
GNSS Signal
Augmentation Info
Augmentation Info
 GNSS (Global Navigation Satellite System) is the satellite navigation
systems that provide autonomous geo-spatial positioning and timing to
any user who has GPS receiver with global coverage,
GPS
GEO Satellite
GNSS

5
History of GNSS
GPS
Program Begin
(1973)
GLONASS begin
(1976)
Galileo approved
(1999)
Beidou1 시작
(1993)
WAAS
IO (2003)
LAAS Certi
(2009)
First Sv
Launch
(1978)
FOC
(1995)
SA Turn
off
(2000)
1st GLONASS SV
Launch (1982)
20 Sv working
(2009)
GPS Modernization
(PDD*) (1996)
GIOVE-A Launch
(2005)
Beidou1
Launch (2000)
Beidou2(COMPASS)
Launch (2003)
QZSS begin
(2002)
IRNSS begin
(2006)
1st QZSS SV
Launch (2009)
IRNSS
Completed
(2012)
Block IIF
Launch (2007)
ICAO recommended (1991)
IMO GNSS regulated
(1997)
USA
RUSSIA
EC
China
Japan
India
* PDD : Presidential Decision Directive
EGNOS
IO (2006)
MSAS IO
(2007)
GAGAN
Completed
(2011)
GPS open to the
Public (1984)
1970년대
1970’s 1970년대
1980’s 1970년대
1990’s 1970년대
2000’s
ICAO, IMO

6
GNSS Basics
5 Monitor Stations
(Worldwide Locations)
Master Control Site
Upload Stations
Space Segment
CONSTELLATION
•MEO satellites
• Couple of orbit planes

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GNSS Applications
EMI EMI
C2
GALILEO
GPS
GLONASS
GPS Compass
IRNSS
QZSS
WAAS
EGNOS
GAGAN
TASS
eLORAN
VOR/DME,
TACAN
ILS, NDB
Tracking
N
S
E
W
Compass
Clock
INS
Celestial
Navigation
Commercial
Augmentations
Time
Transfer
Tercom
Doppler
Commercial
Augmentations
ASI
JPALS
GDGPS
IGS
CORS
WAGE
ZAOD
Time
Transfer
NDGPS
MDGPS
Time
Transfer
Repeater
MTSAT
Cell
Network
PNT
GBAS Cat-I

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GNSS & RNSS
 GNSS-Global Navigation Satellite System
 Consists of MEO
 Worldwide service coverage
 RNSS-Regional Navigation Satellite System
 Consists of HEO, Geo and QZS etc.
 Regional service coverage

9
Status of GNSS & RNSS
GNSS
(Global Navigation
Satellite System)
GPS US Global Positioning System
GLONASS Russian Global Navigation Satellite System
Galileo European GNSS
RNSS
(Regional Navigation
Satellite System)
JRANS Japanese Regional Navigation System
Compass Chinese Satellite Navigation System

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Global Navigation Satellite System

11
GPS History
 The design of GPS is based partly on the similar ground-
based radio navigation systems such as LORAN
developed in early 1940’s
 The first satellite navigation system, Transit, used by the
United States Navy, was first successfully tested in 1960.
Using a constellation of five satellites
 In 1967, the U.S. Navy developed the Timation satellite
which proved the ability to place accurate clocks in space.
 In the 1970s, the ground-based Omega Navigation
System, based on signal phase comparison, became the
first world-wide radio navigation system

12
GPS History
 The first experimental Block-I GPS satellite was launched
in February 1978 (Lockheed Martin)
 In 1983, after Soviet interceptor aircraft shot down the
civilian airliner KAL 007 in restricted Soviet airspace,
killing all 269 people on board, Ronald Reagan
announced that the GPS system would be made available
for civilian uses once it was completed.
 The first modern Block-II satellite was launched on
February 14.
 Achieved initial operational capability by December 1993.

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GPS History
 A complete constellation of 24 satellites was in orbit by
January 17, 1994.
 DoD switched on Selective Availability (SA) in 1990.
 SA was switched off during the Gulf War (1990-91).
 Vice President of US announced about the third
frequency signal(L5) for civil user in February 1997
 SA switched off in May 2000

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GPS Service
 PPS(Precise Positioning Service)
 For military user
 L1, L2, Code & Carrier
 Navigation Message
 SPS(Standard Positioning Service)
 For civil user
 L1 Code & Carrier
 L2 Carrier
 Navigation Message

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GPS Space Segment
 CONSTELLATION
 24 satellites
 6 orbit planes
 12 hour circular orbits
 ~20,000 km altitude
 55 deg inclination
Clock : 4 Atomic Clocks
- 2 Cesium + 2 Rubidium
- Error : 10-13 ~ 10-14 (Block II) => 10-14 ~ 10-15 (Block IIR)
Transmitting Method : CDMA with L-band
- L1 = 1.57542 GHz, L2 = 1.22760GHz.

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GPS Control Segment
 Master Control Station
 5 Monitor Stations
 4 Upload Stations

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GPS Signals
 L1 Signal (1575.42 MHz)
 Navigation Data (50 bps), including
satellite orbits (ephemeris) data
 Code Phase (C/A)
 Carrier Phase
 L2 Signal (1227.6 MHz)
 Navigation Data (50 bps), including
satellite orbits (ephemeris) data
 Code Phase (P/Y): reserved for
military user
 Carrier Phase
 Measurement Precision
 Code Phase: 0.5 ~ 1m
 Carrier Phase: ~ 0.5 cm
Receiver location
Ru(xu, yu, zu)
 Three Satellite measurements
are needed for position estimation.
 4th Satellite measurement is
needed for receiver clock bias.

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GPS Measurements
 Code Phase Measurements
 PR = ρ- δ_SV + δ_rec + δ_Iono + δ_trop + δ_mp
+ δ_noise + ε
 Carrier Phase Measuements
 Φ =ρ+ N - δ_SV + δ_rec - δ_Iono + δ_trop + δ_mp
+ δ_noise + ε
Where PR : pseudorange
Φ : carrier phase measurements
ρ: true distance between sv and receiver
δ_sv : satellite clock bias
δ_rec :receiver clock bias
δ_iono : Ionospheric Error
δ_trop : tropospheric Error
δ_mp : Multipath
δ_noise: Receiver Noise
N : cycle ambiguity
ε : Measurements Error

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GPS Service
 PPS(Precise Positioning Service)
 For Military User only
 L1, L2, C/A-code, P/Y-code & Navigation Message
 SPS(Standard Positioning Service)
 For Civil User
 L1, L2, C/A-code, P-code & Navigation Message

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Selective Availability
 Selective Availability (SA) was an intentional
degradation of public GPS signals implemented for
national security reasons.
 Position Accuracy Degradation
 Off-Setting SV Clocks
 Injection of Ephemeris Error
 Accuracy with SA
 SA On ; ～100m (C/A-code or P-code)
 SA Off ; 20～40m (C/A-code or P-code)
 SA Policy
 Declare to keep SA (1995)
 In 1996, Clinton Announced that SA will be removed within 10
years.
 In 2000, SA off

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Anti-Spoofing
 Anti-Spoofing (A-S) ; The main mechanism for
limiting access to the full capabilities of GPS
has been encryption of the P-code broadcast
on both L1 and L2. This feature is referred to
as Anti-spoofing.
 Encrypted P-code is referred to as a Y-code.
 Access to Y-coded signals requires the crypto-
graphic key.
 DoD makes available to authorized user
 Nothing to do with C/A-code

25
2-D position with SA on & off
SA 해제전(5월 1일)
SA 해제후(5월 3일)

26
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Status of GPS Modernization
- Program
Block IIA/IIR Block III
Block IIR-M, IIF
• Backward compatibility
• 4th civil signal (L1C)
• 4x better User Range
error than IIF
• Increased availability
• Increased integrity
IIR-M: IIA/IIR capabilities plus
• 2nd civil signal (L2C)
• M-Code (L1M & L2M)
IIF: IIR-M capability plus
• 3rd civil signal (L5)
• 2Rb + 1Cs clocks
• 12 year design life
Basic GPS
• Standard Service
– Single frequency (L1)
– Coarse acquisition (C/A)
code navigation
• Precise Service
– Y-Code (L1Y & L2Y)
– Y-Code navigation
Increasing System Capabilities w Increasing Defense / Civil Benefit

27
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 Second civil signal “L2C”
 Designed to meet commercial needs
 Higher accuracy through ionospheric correction
 1st launch: Sep. 2006; 24 satellites: ~2016
 Third civil signal “L5”
 Designed to meet demanding requirements for transportation
safety-of-life
 1st launch: ~2009(GPS IIF); 24 satellites: ~2018
 Fourth civil signal “L1C”
 Designed with international partners for GNSS interoperability
 Begins with GPS Block III
 1st launch: ~2014; 24 satellites: ~2021
- New Civil Signals

28
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 Constellation– the largest ever- 31 healthy
satellites
 13 Block IIA
 12 Block IIR
 6 Block IIR-M
 31st satellite, SVN 23, set healthy, achieved 31 healthy
satellite constellation for first time ever
 Most Recent Launch
 IIR-20(M) – 7th modernized SV
 SVN 49, PRN 1
 Launched 24 Mar. 09
 URE too high
 Transmitting data-less L5 on April 10
 Next Launches
 IIR-21(M) – Aug. 09
 IIF-1 – Oct. 09
- Constellation Status

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- Spectrum

30
GLONASS
 GLONASS (GLObal Navigation Satellite System )
 Developed by Russia
 Designed to use 24 satellites
 Due to lack of funds, 14 satellites are working.
 The system will be FOC.

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GLONASS의 위성궤도
 CONSTELLATION
 24 satellites (14 Sv now)
 3 orbit planes
 11 hours 16 minutes circular orbits
 64.8 deg inclination

32
GLONASS Signal
 GLONASS Signals
 Code Phase : L1 C/A code(0.511MHz, 586m)
L1 & L2 : P code(5.11MHz, 58.7m)
 Carrier Phase : L1 1602MHz – 1615MHz
L2 1246MHz – 1256.5MHz
 Time Frame : UTC(SU) (Russia UTC)

33
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Status of GLONASS Modernization
- State Policy Basic Principles
 GLONASS is a part of the critical state PNT infrastructure providing
national security and economy development
 Creating, developing and sustaining the PNT infrastructure is a State
responsibility
 No direct user fees for civil GLONASS services, open, free access to
GLONASS information necessary to develop and build user
equipment
 Use of GLONASS is mandatory for state entities and major sectors of
economy in Russia
 International cooperation GNSS compatibility and interoperability
Federal GLONASS Program is a basis for State
Policy implementation
Total budget for 2002-2011 is more 100 BRU
Program is to prolong to 2020

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 20 Satellites on orbit
 1 ‘GLONASS’ satellite
 operational
 19 ‘GLONASS-M’ satellites
 18 operational
 1 in maintenance
 Next launches:
 Sep. 09 – 3 ‘GLONASS-M’ satellites
 Dec. 09 – 3 ‘GLONASS-M’ satellites

35
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- Program
Developer NPO PM
Producer PO “Polyot”
Total launched 81 SV
Ordered 1 SV
In orbit 12 SV
Life-time 3 years
Developer NPO PM
Producer NPO PM
Ordered 8 SV
In orbit 2 SV
To be ordered 6
Life-time 7 years
2nd
civil signal
Developer NPO PM
D&D phase
To be ordered up to 27 SV
Life-time 10 years
3rd
civil signal
Requirement definition
since 2002 г.
Ground control segment modernization
Navigation (OD$TS) system modernization
GLONASS augmentation system implementation
System certification for safety of life applications
Search and Rescue service implementation
Supplementary functions (TBD)
GLONASS
GLONASS
1982
1982-
-2007
2007
GLONASS
GLONASS-
-M
M
2003
2003-
-201
2015
5
GLONASS
GLONASS-
-K
K
200
2008
8-
-202
2025
5
GLONASS
GLONASS-
-KM
KM
2015
2015-
-…..
…..
Navigation service market development

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- Signals Forecast
GLONASS-K satellites will transmit CDMA signals in addition to FDMA
Constellation Update based on GLONASS-K
GLONASS-K Flight Tests

37
Galileo Project
 Galileo Project
 Developed by EU
 Development Phase (2002~2007) : development of
the satellites and ground segment
 Deployment Phase (2009~2010) : production and
launching of satellites and the installation of
terrestrial stations and equipment
 Operational Phase (2010~2030)

38
Galileo Constellation
 CONSTELLATION
 30 satellites
 3 orbit planes
 14 hour circular orbits
 56 deg inclination

39
Galileo Service
 Open Services (OS): dual frequency
 Dual Frequency : Horizontal 4m, Vertical 8m ( 99.8%)
 Single Frequency : Horizontal 15m, Vertical 35m
 Commercial Services(CS) : Three -frequency
 Wide Area : 1m
 Local Area: 10cm (Local Augmentation)
 Safety-of-life Services (SOL): Integrity
 Dual Freqeuency : 4 - 6m
 Public Regulated Services(PRS) :
 Wide Area : Horizontal 6.5m, Vertical 12m
 Local Area : 1m
 Search and Rescue Services(SAR)

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Status of GALILEO
 GIOVE A
 3 years in orbit
 Novel orbit, signals and clock
 Galileo filing
 Mission extended
 GIOVE B
 Launched on 27 April 2008
 Most stable clock in space
 Most advanced GNSS signal
 Precursor of IOV

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Status of GALILEO
 IOV status and plans
 Ground Segment CDRs completed
 EM Payload and Satellite test completion
 PFM Satellite integration completion
 Satellite CDR mid 2009
 GMS and GCS commissioning at GCC-I and GCC-D
 GSS, ULS and TTC deployment on remote sites
 IOT station commissioning
 LEOP OCC procurement
 System CDR end 2009
 System Integration and Verification 2009-2010
 Launch in 2010

43
Regional Navigation Satellite System

44
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 Beidou
 Coverage : China
 Satellite constellation
 3 GEO : E 80°, E 110.5°, E 140°
 Frequency
 Up link : L-band (1610 ~ 1626.5 MHz)
 Down link : S-band (2483.5 ~ 2500 MHz)
 Name in ITU : CHINASAT-31/32/33
 COMPASS
 Coverage : global
 Satellite constellation
 9 MEO (altitude 22,000km)
 12 HEO (altitude 36,000km)
 4 GEO : E 58.75°, E 80°, E 110.5 °, E 140°
 Frequency
 Up link : 1300 ~ 1350 MHZ
 Down link : 1164 - 1215MHz, 1260 - 1300MHz
 Name in ITU : COMPASS-H/M/58.75E/80E/110.5E/140E
COMPASS

45
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 2006. 12 China Xinhua
 Announced China National Space Administration
 35 (30 MEO/6 orbit planes, 5 GEO)
 People’s Daily Online
 Two levels of service
 An open, commercial service : 10meter, 50ns
 A safer authorized service : similar to PRS or M
 Status
Date Launcher Satellite Orbit In Use
10/31/2000 LM-3A Beidou-1A GEO 140°E No
12/21/2000 LM-3A Beidou-1B GEO 80°E Yes
5/25/2003 LM-3A Beidou-1C GEO 110.5°E Yes
2/3/2007 LM-3A Beidou-1D GEO 86°E Yes
4/14/2007 LM-3A Beidou-2A MEO 21,500 km Yes
4/15/2009 LM-3C Beidou-2G MEO 21,500 km Yes
COMPASS

46
COMPASS
 PRS, M-code overlay threat?
 COMPASS의 frequency filing (E1/E2/E6/E5b)
 L1의 Galileo PRS와 GPS M-code & overlay
 WRC 2007
 Reviewing the potential interference at ITU WG
 2007. 10~11 issued at WRC 2007
 EU is reviewing the change of PRS frequency

47
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Status of COMPASS
 The 1st step: COMPASS Navigation Demonstration
System
 4 GEO satellites( since 2000)
 Services: Positioning, timing and short-message
telecommunication
 Area: China
 The 2nd step: COMPASS Navigation Satellite System
 5 GEO and not more than 30 MEO satellites
 COMPASS-M1: launched on 13 April 2007
 COMPASS-G2: launched on 14 April 2009
 10 more satellites: ~2010
 30 satellites: ~2015
 Area: Global(Asia-Pacific)

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 Two types of global services
 Open Service: free and open to users
 Positioning Accuracy: 10m
 Timing Accuracy: 20ns
 Velocity accuracy: 0.2m/s
 Authorized Service: ensure highly reliable use
even in complex situation
 Two types of regional services
 Wide area differential service
 Positioning accuracy: 1m
 Short message service
Status of COMPASS
- Services

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 Compatibility and Interoperability
 With multi-systems in sense of signals, geodesy
reference and time reference
 UN/ICG
 With Galileo and GPS
 GNSS receiver test and certification
 Future navigation technology development
 Search and rescue service implementation on
GNSS
Status of COMPASS
- International Cooperation

50
Status of COMPASS
- Observation from CNES on 23 April 2007
50
Compass frequency plan
and Modulation 관측결과 (2007년 4월 23
일)

51
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Status of QZSS- Overview
 A Joint Program
 With the government & private companies (PPP)
 Objective
 Public sector : experiment of a satellite navigation system
 Private sector : three services
 Navigation : L-band, S-band* (* correction data transmission)
 Broadcast : S-band; Communication : S-band
 GOJ has decided to promote the program as a satellite navigation
system after industry’s announcement of difficulty for their
commercial business. (March 31, 2006)
 Single mission : Navigation only by public funding
 Step by step development
– 1st step ; 1st satellite will be launched in 2009
Technical validation and application demonstration
– 2nd Step; 2nd and 3rd satellites launched in several years after
system operation will be demonstrated.

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Status of QZSS- Program
 2005~6: Phase B (August 2007 PDR)
 2007~8: Phase C (August 2008 CDR)
 2008~10: manufacturing, assembly, integration and test
 2010 Summer: Launch QZS-1
3 months later from the launch (for 1 year): In Orbit Validation

53
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Status of QZSS- Planned Signals

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Status of QZSS- Standards
 Time scale: QZSST
 Length of one second is identical to International Atomic Time (TAI)
 Integer second offset for TAI is the same as GPS,
and TAI is 19s ahead of QZSST
 Interface with GPS:
 SV clocks of QZS and GPS satellites are both controlled
with respect to the offset with the GPS time scale (GPST)
 GQTO: Time scale offset with the GPS is less than 2.0 [m] (95%)
 Coordinate System: JGS
 QZSS coordinate system is known as the Japan satellite navigation
Geodetic System(JGS). This coordinate system is operated so as to
approach the International Terrestrial Reference System (ITRS)
 The coordinate system offset with GPS(WGS84) is less than 0.02[m]

55
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Status of QZSS
- Expected Performance (Service Area)

56
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Status of QZSS
- Expected Performance (Accuracy)
 The Signal-in-Space (SIS) User Range Error
 is less than 1.6m (95%) including time and coordination offset
error
 User Positioning Accuracy
 define as positioning accuracy combined GPS L1 C/A and QZSS
L1 C/A for signal frequency user, L1-L2 for dual frequency user
 L1-SAIF signal can provide WDGPS correction data, its positioni
ng accuracy is 1m (1 sigma rms) except in cases of large multi-
path error and large ionospheric disturbance

58
T + 3
Distance between the satellite and receiver
= “3 X speed of light”
T
Signal transmitted at time “T”
Received the signal at
“T + 3”
Range Measurements

59
Speed of light = about 300,000km/sec
Psudorange Measurements

61
3 Dimension Positioning
 Three for x,y,z position, 4th sv is for the
receiver clock bias.

62
Error Sources
Sources Error
SV Clock 0 ~ 1.5m
SV position 5 ~ 20m
Ionosphere 2 ~ 30m
Troposphere 2 ~ 20m
Receiver 10 ~ 10,000m
Multipath 0 ~ 10m
Ephemeris
Satellite Clock
S/A(Selective Availability)
Ionospheric
Tropospheric
Receiver Clock
Receiver Noise
MultiPath
50Km
200Km

64
Ephemeris Error
 Each satellite broadcasts its own orbit ephemeris so user
can compute the satellite location at any time of interest.
 Because the satellite locations are employed to calculate
user position, an error in the satellite ephemeris will result
in a navigation error.

65
Tropospheric & Ionospheric Error

66
Ionospheric Error
 The ionosphere is referred to as the region of the
atmosphere from approx. 50 to 1000 km above the surface
of the earth.
 The degree of the Ionisation of the ionosphere is measured
as total electron content (TEC). The TEC represents the
number of free electrons in a 1-square meter column along
the path from ground through the ionosphere. It is measured
in TEC units, where 1 TEC unit = 1016 electrons/m2.

67
Ionospheric Error
 The TEC depends on the sunspot activities
(approximately 11.-year cycle), seasonal and diurnal
variations, the line of sight which includes elevation and
azimuth of the satellite, and the position of the
observation site. Taking all effects into account, a GPS
pseudorange may be wrong from about 0.15 m to 50 m.
 The Ionospheric Error is the biggest error source in the
GPS signal since SA off in 2000.

68
Tropospheric Error
 The ionosphere is referred to as the region of the
atmosphere approx. max 50 km above the surface of the
earth.
 The propagation through the Troposphere is frequency
independent. An elimination of the tropospheric refraction is
not possible. The refraction index is a function of
temperature, pressure and humidity, thus of the local
weather conditions.

70
Multipath Error
 Signal is not only received directly from the satellite but
from surfaces near the receiving antenna which reflects
the signal.
 Reflections of radio signals from nearby objects
 GPS carrier phase : 0 - 20mm
 GPS pseudoragne : a few meters
 Affects GPS C/A code more than P code

71
Poor (high) DOP Good (low) DOP
Dilution of Precision
N
S
W E
N
S
W E

72
Wireless
Culmination
Synchronization
and Timing
Survey
Ship Navigation
Sea Construction
Climb/Leisure
Goods/Distributions
CNS
Air navigation
Train
Electrical Power
Satellite
Applications

73
Air
Maritime
Rail
Ground
Smart Bomb
Military
robot
Surveying
Agriculture
Earth quake
Time Sync
SAR
Space Science
Trans Mil
Survey Gen
Applications

75
$100 – $400
Perforance
External Memory 8 – 30 M
SC Card extendable
Mapping Software compatible
Portable GPS Receiver

76
$400
$600
HP IPAQ
Pock PC or Cellular Phone

77
 Low cost
 Widely used
 Map matching & DB
Car Navigation

78
Leisure & Sport 1
Hiking Biking
Snowmobile Ski

79
Leisure & Sport 2
골프 낚시
카누

80
Survey/ GIS 사면관리
Agriculture Construction
Agriculture & Construction

82
Using GPS & WVR
Forecast using Water Vapour
Forecast
Meteorological [weather] observation

83
Maritime Applications
AIS, Searching the Gas, construction under water etc.

84
Earth Science
 Monitoring the
movement of earth
crust using GPS

85
Military Application
 PLGR GPS
Receiver
 Replacement of
Manpack in 1993
 PLGR (hand-held
Precision Lightweight
GPS Receiver)
 Known as "Plugger“
 High performance
 Image courtesy Rockwell Collins.

86
Military Application
 Missile Guide etc.
 GPS/INS Implementation

88
Avionic Application
 Aircraft Navigation
 Enroute, Approach and Landing system

89
Navigation Performance
 Accuracy : Accuracy is the measure of the navigation
output deviation from truth under fault-free conditions-
often specified in terms of 95% performance
 Integrity : Integrity is the ability of a system to provide
timely warnings to users when the system should not be
used for navigation.
 Continuity : Continuity is the likelihood that the navigation
signal-in-space supports accuracy and integrity
requirements for the duration of intended operation.
 Availability : Availability is the fraction of time the
navigation function is usable (as determined by its
compliance with the accuracy, integrity, and continuity
requirements).

90
Navigation Performance
Requirements

91
GNSS Satellite
Takeoff
Cruise Metering/De
pproach Landing
Aircraft Navigation

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