GNSS - Global Navigation Satellite System


Satellite Constellations

Your Global Positioning System receiver (GPSr) must utilize information transmitted from one or more satellite constellations to accurately and precisely calculate your current position. Which systems are used and the number of satellite signals available will impact device performance and accuracy.






 

GPS

The Global Positioning System is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The original concept for a Defense Navigation Satellite System (DNSS) in September 1973 was later named Navstar (NAVigation System using Timing And Ranging), then Navstar-GPS to identify the constellation of Navstar satellites, and eventually shortened simply to GPS. Achieving initial operational capability (IOC) in December 1993, Full Operational Capability (FOC) was declared by Air Force Space Command (AFSPC) in April 1995. The highest quality signals were reserved for military use, and the signal available for civilian use was intentionally degraded. Selective Availability was discontinued on May 2, 2000, allowing users to receive a non-degraded signal globally. GPS is maintained by the United States government and is freely accessible to anyone with a GPS receiver.


GLONASS

The GLObal NAvigation Satellite System is a space-based satellite navigation system operated by the Russian Aerospace Defence Forces. It both complements and provides an alternative to the United States' Global Positioning System (GPS) and is the only alternative navigational system in operation with global coverage and comparable precision. GLONASS initially achieved Full Operational Capability (FOC) in December, 1995. Financial difficulties crippled the Russian space program, leaving them with only 6 operational satellites by 2001. In 2010, GLONASS had achieved 100% coverage of Russia's territory, and by October 2011, the full orbital constellation of 24 satellites was restored, enabling full global coverage.


GALILEO

Galileo is the global navigation satellite system (GNSS) that is being created by the European Union (EU) through the European GNSS Agency (GSA), headquartered in Prague in the Czech Republic, with two ground operations centres, Oberpfaffenhofen near Munich in Germany and Fucino in Italy. The project is named after the Italian astronomer Galileo Galilei. Galileo is intended to provide an independent high-precision positioning system so European nations do not have to rely on the Russian GLONASS, Chinese BeiDou or US GPS systems. The first Galileo test satellite, the GIOVE-A, was launched 28 December 2005, while the first satellite to be part of the operational system was launched on 21 October 2011. As of July 2018, 26 of the planned 30 active satellites were in orbit. Galileo started offering Early Operational Capability (EOC) on 15 December 2016, providing initial services with a weak signal, and is expected to reach Full Operational Capability (FOC) in 2019.


 

Iridium

Iridium is the only mobile voice and data satellite communications network that spans the entire globe. It is comprised of six polar orbiting planes, each containing 11 crosslinked satellites totaling 66 in the operational constellation, creating a web of coverage around the Earth. Iridium enables connections between people, organizations and assets to and from anywhere, in real time.


 

GBAS

The Ground Based Augmentation System (also referred to as Local Area Augmentation System in U.S.) is intended primarily to support precision aviation approach operations. GBAS information is transmitted using VHF signals most handheld Garmin GPS receivers are not equipped to receive.


SBAS

A Satellite Based Augmentation System supports wide-area or regional augmentation through the use of additional satellite-broadcast messages.




Satellite Identification

Have you ever considered what the numbers assigned to each GPS satellite on your Garmin GPSr represent, or how they are determined?



PRN

Standard Assignment

NMEA

Garmin Assignment

Garmin NMEA Conversion
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01-32

GPS

01-32

GPS

NMEA = PRN
33-63

GPS






64-96

GBAS

65-88

GLONASS

NMEA = GLONASS Slot Number + 64
97-119

GBAS

 



120-138

SBAS

33-51

SBAS

NMEA = SBAS PRN - 87
139-158

SBAS Expansion/Testing

52-71

SBAS

NMEA = SBAS PRN - 87
159-210

Future GNSS






E01-E36   GALILEO   01-36   GALILEO   NMEA = PRN (no "E" prefix)




Satellite Tracking


PRN NMEA System NORAD Identification Notes
           
01 01 GPS 37753 SVN 63 (Navstar 66) USA-232  
02 02 GPS 28474 SVN 61 (Navstar 56) USA-180  
03 03 GPS 40294 SVN 69 (Navstar 72) USA-258  
04 04 GPS     Decommissioned 03NOV15
05 05 GPS 35752 SVN 50 (Navstar 64) USA-206 (IIR-3) (IIR-21)
06 06 GPS 39741 SVN 67 (Navstar 70) USA-251  
07 07 GPS 32711 SVN 48 (Navstar 62) USA-201 (IIR-19)
08 08 GPS 40740 SVN 72 (Navstar 74) USA-262  
09 09 GPS 40105 SVN 68 (Navstar 71) USA-256  
10 10 GPS 41019 SVN 73 (Navstar 75) USA-265  
11 11 GPS 25933 SVN 46 (Navstar 46) USA-145  
12 12 GPS 29601 SVN 58 (Navstar 59) USA-192 (IIR-16)
13 13 GPS 24876 SVN 43 (Navstar 43) USA-132  
14 14 GPS 26605 SVN 41 (Navstar 49) USA-154  
15 15 GPS 32260 SVN 55 (Navstar 60) USA-196 (IIR-17)
16 16 GPS 27663 SVN 56 (Navstar 51) USA-166  
17 17 GPS 28874 SVN 53 (Navstar 57) USA-183  
18 18 GPS 22877 SVN 34 (Navstar 35) USA-96  
19 19 GPS 28190 SVN 59 (Navstar 54) USA-177  
20 20 GPS 26360 SVN 51 (Navstar 47) USA-150  
21 21 GPS 27704 SVN 45 (Navstar 52) USA-168  
22 22 GPS 28129 SVN 47 (Navstar 53) USA-175  
23 23 GPS 28361 SVN 60 (Navstar 55) USA-178  
24 24 GPS 38833 SVN 65 (Navstar 67) USA-239  
25 25 GPS 36585 SVN 62 (Navstar 65) USA-213 First to broadcast operational L5 signal
26 26 GPS 40534 SVN 71 (Navstar 73) USA-260  
27 27 GPS 39166 SVN 66 (Navstar 68) USA-242 Launched 15MAY13, Enabled 21JUN13
28 28 GPS 26407 SVN 44 (Navstar 48) USA-151  
29 29 GPS 32384 SVN 57 (Navstar 61) USA-199 (IIR-18)
30 30 GPS 39533 SVN 64 (Navstar 69) USA-248 (GPS 2F-5)
31 31 GPS 29486 SVN 52 (Navstar 58) USA-190 (IIR-15)
32 32 GPS 41328 SVN 70 (Navstar 76) USA-266  
         
PRN NMEA System NORAD Identification Notes
           
120 33 SBAS 24307 Inmarsat 3-F2 (AOR-E) (174 W)
121 34 SBAS 25153 Inmarsat 3-F5 (EMEA) (25 E) (APR 2024)
122 35 AUS-NZ 28628 Inmarsat 4-F1 (143.5 E) (JAN 2019)
123 36 EGNOS 39617 Astra 5B (31.5 E) (NOV 2021)
124 37 SBAS 26863 ARTEMIS (76.8 E) (APR 2024)
125 38 SDCM 37951 Luch-5A (16 W) (DEC 2021)
126 39 EGNOS 28899 Inmarsat 4-F2 (IOR-W) (63.9 E) (APR 2019)
127 40 GAGAN 37605 GSAT-8 (55 E) (SEP 2020)
128 41 GAGAN 38779 GSAT-10 (83 E) (SEP 2020)
129 42 MSAS 28622 MTSAT-1R (148 E) (JAN 2020) (Himawari 6)
130 43 SNAS   BDSBAS (G6) (80 E) (OCT 2020)
131 44 WAAS 41589 Eutelsat 117 West B (117 W) (MAR 2028)
132 45 GAGAN 41028 GSAT-15 (93.5 E) (NOV 2025)
133 46 WAAS 33278 Inmarsat 4-F3 (98 W) (OCT 2029)
134 47 KAAS 40882 Inmarsat 5-F3 (178 E) (JUN 2021)
135 48 WAAS 28884 Galaxy 15 (133 W) (JUL 2019)
136 49 EGNOS 38652 SES 5 (5 E) (NOV 2021) (a.k.a. Sirius 5 or Astra 4B)
137 50 MSAS 28937 MTSAT-2 (145 E) (JAN 2020) (Himawari 7)
138 51 WAAS 28868 Anik F1-R (107.3 W) (JUL 2022)
         

Slot NMEA System NORAD Identification Notes
           
01 65 GLONASS 36111 730 (COSMOS 2456) GN 65
02 66 GLONASS 39155 747 (COSMOS 2485) GN 66
03 67 GLONASS 37867 744 (COSMOS 2476) GN 67
04 68 GLONASS 37829 742 (COSMOS 2474) GN 68
05 69 GLONASS 43508 756 (COSMOS 2527) GN 69
06 70 GLONASS 36112 733 (COSMOS 2457) GN 70
07 71 GLONASS 37868 745 (COSMOS 2477) GN 71
08 72 GLONASS 37869 743 (COSMOS 2475) GN 72
09 73 GLONASS 40315 702 (COSMOS 2501) GN 73
10 74 GLONASS 29671 717 (COSMOS 2426) GN 74
11 75 GLONASS 41554 753 (COSMOS 2516) GN 75
12 76 GLONASS 44299 758 (COSMOS 2534) GN 76
13 77 GLONASS 32393 721 (COSMOS 2434) GN 77
14 78 GLONASS 42939 752 (COSMOS 2522) GN 78
15 79 GLONASS 43687 757 (COSMOS 2529) GN 79
16 80 GLONASS 37139 736 (COSMOS 2464) GN 80
17 81 GLONASS 41330 751 (COSMOS 2514) GN 81
18 82 GLONASS 39620 754 (COSMOS 2492) GN 82
19 83 GLONASS 32275 720 (COSMOS 2433) GN 83
20 84 GLONASS 32276 719 (COSMOS 2432) GN 84
21 85 GLONASS 40001 755 (COSMOS 2500) GN 85
22 86 GLONASS 36400 731 (COSMOS 2459) GN 86
23 87 GLONASS 36402 732 (COSMOS 2460) GN 87
24 88 GLONASS 36401 735 (COSMOS 2461) GN 88
         

PRN NMEA System NORAD Identification Notes
           
E01 01 GALILEO 41550 GALILEO 13 (26A)  
E02 02 GALILEO 41549 GALILEO 14 (26B)  
E03 03 GALILEO 41860 GALILEO 16 (26C)  
E04 04 GALILEO 41861 GALILEO 17 (26D)  
E05 05 GALILEO 41862 GALILEO 18 (26E)  
E06 06 GALILEO      
E07 07 GALILEO 41859 GALILEO 15 (267)  
E08 08 GALILEO 41174 GALILEO 11 (268)  
E09 09 GALILEO 41175 GALILEO 12 (269)  
E10 10 GALILEO      
E11 11 GALILEO 37846 GALILEO-PFM  
E12 12 GALILEO 37847 GALILEO-FM2  
E13 13 GALILEO 43567 GALILEO 24 (2C0)  
E14 14 GALILEO 40129 GALILEO 6 (262)  
E15 15 GALILEO 43564 GALILEO 25 (2C1)  
E16 16 GALILEO      
E17 17 GALILEO      
E18 18 GALILEO 40128 GALILEO 5 (261)  
E19 19 GALILEO 38857 GALILEO-FM3  
E20 20 GALILEO 38858 GALILEO-FM4 Payload power problem 27MAY14
E21 21 GALILEO 43055 GALILEO 19 (2C5)  
E22 22 GALILEO 40545 GSAT0204 Removed from active service 08DEC17
E23 23 GALILEO      
E24 24 GALILEO 40889 GALILEO 9 (205)  
E25 25 GALILEO 43056 GALILEO 20 (2C6)  
E26 26 GALILEO 40544 GSAT0203  
E27 27 GALILEO 43057 GALILEO 21 (2C7)  
E28 28 GALILEO      
E29 29 GALILEO      
E30 30 GALILEO 40890 GALILEO 10 (206)  
E31 31 GALILEO 43058 GALILEO 22 (2C8)  
E32 32 GALILEO      
E33 33 GALILEO 43565 GALILEO 26 (2C2)  
E34 34 GALILEO      
E35 35 GALILEO      
E36 36 GALILEO 43566 GALILEO 23 (2C9)  


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