International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 5

Number 1

March 2011

1 INTRODUCTION

Nowadays (January 2011) the American GPS

Satellite Navigation System (SNS) is fully

operational with 31 satellites. Since few years the

Russian GLONASS system was being revamped and

undergoing an extensive modernization effort,

therefore today this system with 21 satellites can be

used for fix position also. Galileo system (Europa)

and Compass system (China) are under construction,

must likely these systems will be operating at the

earliest in 2016 and 2021 adequately.

The Satellite Based Augmentation Systems

(SBAS) that enhance the integrity, accuracy, and

operation of two SNS – GPS and GLONASS. Today

the SBAS as Wide Area Augmentation System

(WAAS), Multi-functional Transport Satellite Based

Augmentation System (MSAS) and European

Geostationary Navigation Overlay System (EGNOS)

are accessible in USA and Canada, Japan and

Europe and North Africa adequately. While WAAS

and MSAS are fully operational since few years,

EGNOS officially entered into operational phase

with the provision of the Open Service as of only

October 1, 2009. Additionally the Department of

Defense of the United States is cooperating with In-

dia to develop new system over Indian space. This is

the GAGAN (GPS and Geo Augmented Naviga-

tion), new SBAS, actually under construction. Other

SBAS will enhance GLONASS and GPS systems,

called SDCM (System for Differential Correction

and Monitoring), is under construction in Russia. All

these SNS and SBAS create Global Navigation

Satellite System (GNSS). System Compass was

nottaken into account in this paper, because about

this system little information is available still.

2 SATELLITE NAVIGATION SYSTEMS

CONSTELLATION

Actually (January 2011) GPS spatial segment con-

sists of 32 satellites, 11 the oldest block IIa, 12 block

IIR, 8 block IIR–M and 1 block IIF (Table 1)

[www.navcen.uscg.gov]. Additionally in this table

we can find the information about active life of each

satellite in years and months. The value of this life

depends on the system and satellite block. The mean

values of these satellites life of block IIA, IIR and

IIR–M are equal 16.3, 8.9 and 3.2 years adequately.

It means that the active life of all satellites of block

IIA is greater than nominal value 10 years, conside-

rably. The satellites IIA and IIR transmit one frequ-

ency (L1) for civil users only, IIR–M two frequen-

cies (L1, L2), IIF and the future III three (L1, L2,

L5). Information about integrity will provide the sa-

tellites block III only [Gleason S., Gebre-Egziabher

D. 2009] and [Hofmann-Wellenhof B. et all. 2008].

The GLONASS spatial segment consists of 21

satellites, all block M (Table 2), which transmit two

frequencies for civil users (L1, L2), but without in-

formation about integrity [www.glonass-ianc.rsa.ru].

This information and the third frequency will be

provided by the satellites next generation K. The

A Look at the Development of GNSS

Capabilities Over the Next 10 Years

J. Januszewski

Gdynia Maritime University, Gdynia, Poland

ABSTRACT: This paper considers what the SNS (Satellite Navigation Systems) as GPS, GLONASS, Galileo

and Compass, and SBAS (Satellite Based Navigation Systems) as EGNOS, WAAS, MSAS and GAGAN ser-

vices might look like 10 years from now. All these systems, called GNSS (Global Satellite Navigation Sys-

tem), are undergoing construction or modernization (new satellites, new frequencies, new signals, new moni-

toring stations, etc.) and continuous improvement to increase its accuracy, availability, integrity, and

resistance to interference. The most significant events in SNS and SBAS in the nearest 10 years are presented

also. Additionally three possible scenarios considering these systems (in 2016 and 2021 years), concerning

the number of satellites in particular, optimistic, pessimistic and the most probable were taken into account.

Galileo spatial segment consists of 2 satellites only,

27 operational and 3 active spheres in the future.

The satellites will transmit four frequencies.

The accuracy of the user’s position obtained from

the SNS depends on a number of satellites (ls)

visible above masking angle. That’s why the total

number of satellites, fully operational especially, is

very interesting for the users. There is no direct

relation between the number ls and the position error

M, but for all SNS in the case of position fix in

restricted area we can say the following “when ls

greater, M is less” and inversely “when ls is less, M

is greater” [Januszewski J. 2008].

3 THE MOST SIGNIFICANT EVENTS IN THE

GNSS IN THE NEAREST 10 YEARS

The most significant events in the SNS and SBAS

waited in optimistic scenario into 10 nearest years

(2012–2021) with the consequences for the civil u-

sers are presented in Table 3. One of the parameters

mentioned in this table is the number of frequencies

transmitted by the satellites of each SNS. Because of

two or three frequencies make possible the

calculation of ionosphere correction, the user’s

position accuracy increases. Unlike actual

generation of GPS and GLONASS systems next

generation of these systems, GPS III and GLONASS

K, and new system Galileo will provide integrity

information. Integrity can be defined as a reliability

indicator of the quality of positioning, user’s

position obtained from SNS also [Januszewski J.

2009].

EGNOS has claimed that they will eventually

transmit integrity information for users of GPS and

GLONASS systems as well as for Galileo system.

Between 2008 and 2013, the FAA (Federal Avia-

tion Administration) will make the necessary chan-

ges in the ground equipment of WAAS to handle the

L5 signal from GPS. Having two frequencies for io-

nospheric corrections will eliminate loss of vertical

guidance caused by ionospheric storms.

Japan has had a plan to display a new regional

system called the Quasi–Zenith Satellite System

(QZSS), which services include enhanced accuracy

GPS signals, communications and broadcasting.

The GPS and GLONASS systems are undergoing

uninterrupted modernization (new satellites, new

frequencies, new signals, new codes, new monito-

ring stations, etc.) and continuous improvement to

increase its accuracy (position in particular), availa-

bility, integrity, and resistance to interference, while

at same time maintaining at least the performance it

enjoys today with existing already user’s receivers

[Januszewski J. 2010] and [Springer T., Dach R.

2010]. In the case of the GPS system the plans of the

control segment modernization are well known. The

next Generation GPS Control Segment (OCX) will

provide significant benefits to all users around the

world, as well as to GPS operators, mainters, and

analysts. Two major upgrades are in development;

the Legacy Accuracy Improvement Initiative (L-AII)

and the Architecture Evolution Plan (AEP). The L-

AII upgrade adds up to 14, actually 11 only,

National Geospatial Intelligence Agency (NGA)

monitor stations [Kaplan E.D., Hegarty C.J. 2006],

[Gower A. 2008].

United States Air Force officials are moving to

reconfigure the GPS constellation to create as soon

as possible a 27 satellites geometry that will improve

the availability and accuracy of positioning,

navigation, and timing capabilities, in particular for

U.S. military forces [Roper E. 2010].

A third civil signal at the GLONASS L3

frequency will be on newer GLONASS K satellites,

probably starting in 2011 (Table 3).

The first two in–orbit validation (IOV) Galileo

satellites are scheduled for launch 2011, followed by

two more in next year.

4 THE POSSIBLE SCENARIOS AFFECTING

THE DEVELOPMENT OF GNSS

Three possible scenarios considering three SNS, the

GPS, GLONASS and Galileo, and SBAS in 2016

and 2021 years, optimistic, pessimistic and the most

probable were taken into account [Lavrakas J.W.

2007]. The projected total number of satellites,

number of satellites transmitting signals for civil

users on two and three frequencies and information

about integrity for GPS, GLONASS and Galileo for

each mentioned above scenario are presented in the

author’s Table 4.

4.1 Optimistic scenario

In this scenario every project meets its projected

dates. In the case of GPS system the following

assumptions are made for 2016 year:

− all 12 Block IIF and 4 Block III satellites were

launched,

− as in 2011 the satellites IIA launched in 1992 or

earlier are fully operational still, we can expect

that in 2016 years the vitality of all satellites on

orbit will be also 20 years.

In this situation we have in GPS satellites:

− 12 Block IIFs ranging from 0 to 6 years old,

− 8 Block IIR–Ms ranging from 7 to 11 years old,

− 12 Block IIRs ranging from 12 to 18 years old,

− 4 Block IIAs ranging from 19 to 20 years old,

− 4 Block IIIs ranging from 0 to 2 years old.

It means that the GPS spatial segment will consist

of 40 satellites. As this number is greater than 32

(nominal value), 8 oldest satellites will be able to be

not used. In 2016 year two other SNS the

GLONASS and Galileo systems are operational with

24 satellites M and few satellites K, and at least 18

satellites adequately.

In this scenario for 2021 year all three systems

GPS, GLONASS and Galileo are fully operational,

all satellites of these systems transmit at least three

frequencies accessible for civil users and the signals

contain the integrity information. The GPS spatial

segment will consist of at least 24 satellites of Block

III, 12 satellites of Block IIF and perhaps all

satellites of Block IIR–M and few of Block IIR. The

spatial segments of GLONASS and Galileo will

consist of 30 satellites of new Block K and 30

adequately.

In this optimistic scenario, already in 2016 year,

all present-day SBAS, and GAGAN and QZSS also,

will be fully operational, and perhaps in 2021 year

other new systems (e.g. in Africa and in South

America) additionally.

4.2 Pessimistic scenario

In this scenario no project is not realized according

to earlier plan. In the case of GPS system the

following assumptions are made for 2016 year:

− 8 Block IIF satellites were launched only,

− the block III did not begin,

− the vitality of all satellites on orbit are at most

equal nominal. It means that the satellites of

Block IIR and earlier are out of service.

In this situation we have in satellites: 8 Block

IIFs ranging from 0 to 6 years old and 8 Block IIR–

Ms ranging from 7 to 11 years old, that is to say 16

satellites only. It means that user’s position cannot

be obtained at any point on Earth and at any

moment.

In 2016 year the number of Galileo satellites fully

operational is less than planned 18, therefore this

system is still under construction. The number of

GLONASS satellites, all kind M, is less than 24

again. The works over the next satellite generation K

continually last.

In scenario for 2021 year GPS spatial segment

will consist at most of 12 satellites of Block IIF and

few satellites of Block III only. As the vitality of all

GPS satellites are at most equal nominal, the

satellites of Block IIR–M and earlier are already out

of service. The GLONASS spatial segment will

consist at most of 24 satellites M and few satellites

K only. The date of FOC (Full Operational

Capability) of Galileo system continually lengthens,

the number of satellites is less than nominal 27 still.

In this pessimistic scenario in 2016 and 2021

years EGNOS, WAAS and MSAS are fully

operational, but without additional geostationary

satellites. GAGAN and QZSS are under construction

still.

4.3 The most probable scenario

All systems are undergoing modernization or

construction, but time-limits are not kept.

The last launch of GPS IIF satellite and the first

launch of GPS III satellite will be not in 2014 years,

but several years later. The vitality of GPS satellites

is continually the same as at present, for the most

satellites greater than nominal. In this situation in

2016 year we have in satellites: at most 10 Block

IIRs ranging from 12 to 16 years old, 8 Block IIR–

Ms ranging 7 to 11 years old and 12 Block IIFs

ranging from 0 to 6 years old. The construction of

Galileo system became finished, but the number of

satellites is 18 only. The spatial segment of the

GLONASS system consists of 24 satellites M only.

In this scenario in 2021 year we have in GPS

satellites: 12 Block IIIs ranging from 0 to 5 years

old, 12 Block IIF ranging from 5 to 11 years old and

about 8 Block IIR–Ms ranging from 12 to 16 years

old. The Galileo system with the number of satellite

between 27 and 30 is fully operational. The

GLONASS system will consist of about 30 satellites

M and K, in the most of the block M.

In the most probable scenario GAGAN and

QZSS systems will be fully operational before 2016

year, but in 2021 year other new SBAS will be under

construction or on the stage projects.

5 CONCLUSIONS

− in the case of GPS system the kind of scenario

will depend on vitality of his satellites, of Block

IIR–M in particular. If this vitality will be equal a

dozen or so years, as in earlier blocks, scenario

will be optimistic,

− in the case of the GLONASS and Galileo systems

the kind of scenario will depend on time-limit of

the implementation of all improvements,

− in optimistic scenario in 2021 GPS, GLONASS

and Galileo systems offer full service on all 32,

24 and 27 satellites, adequately and information

about integrity; five years earlier integrity

provides the Galileo system only,

− in pessimistic scenario in 2021 one only SNS, the

GLONASS system, offers full service, the

number of GPS satellites is less than nominal 24,

the Galileo system is under construction still; five

years earlier all these three SNSs are not fully

operational,

− in the most probable scenario in 2021 all three

SNSs are fully operational, but in each system

information about integrity can be obtained only

from the part of his satellites; five years earlier

this information is provided by the part of GPS

and Galileo satellites only.

REFERENCES

Gleason S., Gebre-Egziabher D. 2009. GNSS Applications and

Methods, Artech House, Boston/London.

Gower A. 2008. The System: The Promise of OCX, GPS

World, No 8, vol.19.

Hofmann-Wellenhof B. et all. 2008. GNSS–Global Navigation

Satellite Systems GPS, GLONASS, Galileo & more,

SpringerWienNewYork, Wien.

Januszewski J. 2010. Visibility and geometry of combined

constellations GPS with health in question, GLONASS and

Galileo, p. 1082−1094, Institute of Navigation,

International Technical Meeting, San Diego (CA).

Januszewski J. 2009. Satellite navigation systems integrity

today and in the future, Monograph “Advances in Transport

Systems Telematics”, p. 123−132, Edited by Jerzy

Mikulski, Wydawnictwa Komunikacji i Łączności,

Warszawa.

Januszewski J. 2010. Nawigacyjny system satelitarny GPS

dzisiaj i w przyszłości, p. 17–29, Prace Wydziału

Nawigacyjnego nr 24, Akademia Morska, Gdynia (in

polish).

Kaplan E.D. & Hegarty C.J. 2006. Understanding GPS

Principles and Applications, Artech House, Boston/London.

Lavrakas J.W. 2007. A Glimpse into the Future: A Look at

GNSS in the Year 2017, p. 210−217, Institute of

Navigation, National Technical Meeting, San Diego (CA).

Roper E. 2010. GPS Status and Modernization, Munich

Satellite Navigation Summit, Munich.

Springer T., Dach R. 2010. GPS, GLONASS, and More

Multiple Constellation Processing in the International

GNSS Service, GPS World, No 6, vol.21.

www.glonass-ianc.rsa.ru

www.navcen.uscg.gov

Table 1. GPS System, PRN – Pseudorandom noise number, SVN – Space Vehicle Number, launch and input dates, active life and

mean active life in years and months of all 32 satellites in January 21, 2011

__________________________________________________________________________________________________________

Block PRN SVN Launch date Input date Active life Mean active life

years months years months

__________________________________________________________________________________________________________

IIA–10 32 23 26.11.1990 10.12.1990 16 0.8

IIA–11 24 24 04.07.1991 30.08.1991 19 1.3

IIA–14 26 26 07.07.1992 23.07.1992 18 5.8

IIA–15 27 27 09.09.1992 30.09.1992 18 3.2

IIA–21 9 39 26.06.1993 20.07.1993 17 4.8

IIA–23 4 34 26.10.1993 22.11.1993 17 2.0 16 3.1

IIA–24 6 36 10.03.1994 28.03.1994 16 9.0

IIA–25 3 33 28.03.1996 09.04.1996 14 8.1

IIA–26 10 40 16.07.1996 15.08.1996 14 4.4

IIA–27 30 30 12.09.1996 01.10.1996 14 2.8

IIA–28 08 38 06.11.1997 18.12.1997 13 0.2

__________________________________________________________________________________________________________

IIR–2 13 43 23.07.1997 31.01.1998 12 11.6

IIR–3 11 46 07.10.1999 03.01.2000 11 0.6

IIR–4 20 51 11.05.2000 01.06.2000 10 7.5

IIR–5 28 44 16.07.2000 17.08.2000 10 5.2

IIR–6 14 41 10.11.2000 10.12.2000 10 1.3

IIR–7 18 54 30.01.2001 15.02.2001 9 11.1 8 11.0

IIR–8 16 56 29.01.2003 18.02.2003 7 10.9

IIR–9 21 45 31.03.2003 12.04.2003 7 7.2

IIR–10 22 47 21.12.2003 12.01.2004 7 0.3

IIR–11 19 59 20.03.2004 05.04.2004 6 9.5

IIR–12 23 60 23.06.2004 09.07.2004 6 6.3

IIR–13 2 61 06.11.2004 22.11.2004 6 1.9

__________________________________________________________________________________________________________

IIR–14M 17 53 26.09.2005 13.11.2005 5 1.1

IIR–15M 31 52 25.09.2006 13.10.2006 4 3.3

IIR–16M 12 58 17.11.2006 13.12.2006 4 1.1

IIR–17M 15 55 17.10.2007 31.10.2007 3 2.7 3 1.8

IIR–18M 29 57 20.12.2007 02.01.2008 3 0.6

IIR–19M 7 48 15.03.2008 24.03.2008 2 9.9

IIR–20M 1 49 24.03.2009 in commissioning phase

IIR–21M 5 50 17.08.2009 27.08.2009 1 4.8

__________________________________________________________________________________________________________

IIF–1 25 62 28.05.2010 27.08.2010 0 4.8 0 4.8

__________________________________________________________________________________________________________

Table 2 GLONASS System, orbit/slot, frequency channel, GLONASS number, launch and input dates, active life and mean active

life in years and months of all 21satellites in January 21, 2011

__________________________________________________________________________________________________________

Orbit / slot Frequency channel GLONASS number Launch date Input date Life time Mean life time

years months years months

__________________________________________________________________________________________________________

I / 1 01 730 14.12.2009 30.01.2010 1 1.2

I / 2 – 4 728 25.12.2008 20.01.2009 2 0.9

I / 3 satellite 727 in maintenance

I / 4 without satellite

I / 5 01 734 14.12.2009 10.01.2010 1 1.2

I / 6 – 4 733 14.12.2009 24.01.2010 1 1.2

I / 7 05 712 26.12.2004 07.10.2005 6 0.9

I / 8 06 729 25.12.2008 12.02.2009 2 0.9

II / 9 – 2 736 02.09.2010 04.10.2010 0 4.6

II / 10 – 7 717 25.12.2006 03.04.2007 4 0.9

II / 11 00 723 25.12.2007 22.01.2008 3 0.9

II / 12 – 1 737 02.09.2010 04.10.2010 0 4.6 2 2.2

II / 13 – 2 721 25.12.2007 08.02.2008 3 0.9

II / 14

– 7 722 25.12.2007 25.01.2008 3 0.9

II / 15 00 716 25.12.2006 12.10.2007 4 0.9

II / 16 – 1 738 02.09.2010 04.10.2010 0 4.6

III / 17 satellites 714 and 728 in maintenance

III / 18 –3 724 25.09.2008 26.10.2008 2 3.9

III / 19 03 720 26.10.2007 25.11.2007 3 2.9

III / 20 02 719 26.10.2007 27.11.2007 3 2.9

III / 21 04 725 25.09.2008 05.11.2008 2 3.9

III / 22

-3 731 02.03.2010 28.03.2010 0 10.7

III / 23 03 732 02.03.2010 28.03.2010 0 10.7

III / 24 02 735 02.03.2010 28.03.2010 0 10.7

__________________________________________________________________________________________________________

– additional satellite 715 in maintenance,

– additional satellite 726 in maintenance

Table 3. The most significant events in the satellite navigation systems and satellite based augmentation systems in the nearest 10

years and their consequences for users

__________________________________________________________________________________________________________

Year Event Consequences for users

__________________________________________________________________________________________________________

2010 three GLONASS M satellites crashed into Full Operational Capability of GLONASS system cannot be obtained

Pacific Ocean after a failed launch

first launch of QZSS spacecraft Michibiki for the first time in history the signal L1C is transmitted in space

additional launches of Compass satellites new GEO, IGSO and MEO satellites of China’s system

__________________________________________________________________________________________________________

2011 24 GLONASS M satellites two SNS systems (GLONASS and GPS) fully operational

all GAGAN satellites on geostationary orbit GAGAN – Indian SBAS fully operational

the first launch of GLONASS K satellite the beginning of the new generation of GLONASS satellite

the first use of code division multiple access CDMA

__________________________________________________________________________________________________________

2012 third SDCM satellite on geostationary orbit SDCM – Russian SBAS fully operational

__________________________________________________________________________________________________________

2013 WAAS – two frequencies (L1 and L5) elimination of vertical guidance caused by ionospheric storms

for ionospheric corrections

__________________________________________________________________________________________________________

2014 the first launch of GPS III A satellite the beginning of the third generation of GPS system

__________________________________________________________________________________________________________

2015 Full Operational Capability of the next continuous L-band tracking coverage of the GPS constellation

Generation GPS Control Segment (OCX) additional features and functionality of control segment (CS)

Galileo constellation with 18 satellites for the first time in history, integrity information about SNS

(4 IOV and 14 fully operational) for the users of the all the world, Initial Operational Capability (IOC)

__________________________________________________________________________________________________________

2016 24 GPS satellites transmitting L2C full access to two civil frequencies

__________________________________________________________________________________________________________

2018 24 GPS satellites transmitting L5 full access to three civil frequencies

Galileo constellation 27–30 satellites full access to all signals and services, Full Operational Capability (FOC)

__________________________________________________________________________________________________________

2019 30 GLONASS K satellites full access to three civil frequencies, integrity information about system

__________________________________________________________________________________________________________

2020 35 Compass satellites fully operational full access to all signals and services

(5 GEO, 27 MEO and 3 IGSO)

__________________________________________________________________________________________________________

2021 24 GPS satellites block III transmitting L1C full access to new block III, integrity information and new signal L1C

__________________________________________________________________________________________________________

Table 4. The projected total number of satellites, number of satellites transmitting signals for civil users on two and three

frequencies and information about integrity for different satellite navigation systems and for different scenarios in 2016 and 2021

years

__________________________________________________________________________________________________________

Year Scenario System Number of satellites Integrity

total with two frequencies with three frequencies of the system

__________________________________________________________________________________________________________

2016 optimistic GPS 40 24 16 non

GLONASS at least 24 at least 24 several non

Galileo at least 18 at least 18 at least 18 yes

Total at least 82 at least 66 at least 40 –

pessimistic GPS 16 8 8 non

GLONASS less than 24 less than 24 0 non

Galileo less than 18 less than 18 less than 18 non

Total less than 58 less than 50 less 26 –

the most GPS at most 30 at most 20 12 non

probable GLONASS 24 24 0 non

Galileo 18 18 18 yes

Total at most 72 at most 62 30 –

__________________________________________________________________________________________________________

2021 optimistic GPS at least 44 at least 44 24 yes

GLONASS 30 30 30 yes

Galileo 30 30 30 yes

Total at least 104 at least 104 84 –

pessimistic GPS a dozen or so a dozen or so a dozen or so non

GLONASS at most twenty several at most 24 several non

Galileo less than 27 less than 27 less than 27 non

Total about 65 about 60 about 45 –

the most GPS about 32 about 32 24 non

probable GLONASS about 30 a dozen or so a dozen or so non

Galileo 27 ÷ 30 27 ÷ 30 27 ÷ 30 yes

Total about 89 ÷ 92 about 73 ÷ 79 about 63 ÷ 72 –

__________________________________________________________________________________________________________