GPS Navigation Message - Revision history

Jalbert: Small fix in LNAV sub-frames 4 and 5.

2026-06-01T08:31:33Z

Small fix in LNAV sub-frames 4 and 5.

← Older revision		Revision as of 08:31, 1 June 2026
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	* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.		* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.
	Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.		Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.
	The content of sub-frames 4 and 5 can ~~differ~~ between satellites. Furthermore, within the GPS LNAV navigation data structure, these subframes can differ depending on whether the PRN numbers belong to the lower set (1–32) or the upper set (33–63).		The content of sub-frames 4 and 5 can be different between satellites. Furthermore, within the GPS LNAV navigation data structure, these subframes can differ depending on whether the PRN numbers belong to the lower set (1–32) or the upper set (33–63).

	Further information on the LNAV message can be found in IS-GPS-200 ICD document <ref name="GPS ICD 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision N, "Navstar GPS Space Segment/Navigation User Segment Interfaces"]</ref>.		Further information on the LNAV message can be found in IS-GPS-200 ICD document <ref name="GPS ICD 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision N, "Navstar GPS Space Segment/Navigation User Segment Interfaces"]</ref>.

Jalbert: Small fix in LNAV sub-frames 4 and 5.

2026-06-01T08:29:46Z

Small fix in LNAV sub-frames 4 and 5.

← Older revision		Revision as of 08:29, 1 June 2026
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	* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.		* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.
	Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.		Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.
	The content of sub-frames 4 and 5 ~~is common for all~~ satellites. ~~Thence~~, the ~~almanac~~ data ~~for all in orbit satellites~~ can ~~be obtained from a single tracked satellite~~.		The content of sub-frames 4 and 5 can differ between satellites. Furthermore, within the GPS LNAV navigation data structure, these subframes can differ depending on whether the PRN numbers belong to the lower set (1–32) or the upper set (33–63).

	Further information on the LNAV message can be found in IS-GPS-200 ICD document <ref name="GPS ICD 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision N, "Navstar GPS Space Segment/Navigation User Segment Interfaces"]</ref>.		Further information on the LNAV message can be found in IS-GPS-200 ICD document <ref name="GPS ICD 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision N, "Navstar GPS Space Segment/Navigation User Segment Interfaces"]</ref>.

Natalia.Castrillo at 09:54, 28 January 2026

2026-01-28T09:54:03Z

← Older revision		Revision as of 09:54, 28 January 2026
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	The CNAV-2 is modulated onto L1C signal, sharing the same band as the "legacy" LNAV navigation message.		The CNAV-2 is modulated onto L1C signal, sharing the same band as the "legacy" LNAV navigation message.

	Further information on the different navigation messages can be found in the respective GPS Interface Control Documents (ICD) available at [https://archive.gps.gov/technical/icwg/ GPS Official Website]<ref name="GPS GOV Webpage">[https://archive.gps.gov/]</ref>.		Further information on the different navigation messages can be found in the respective GPS Interface Control Documents (ICD) available at [https://archive.gps.gov/technical/icwg/ GPS Official Website] <ref name="GPS GOV Webpage">[https://archive.gps.gov/ Official U.S. government information about the Global Positioning System (GPS)]</ref>.

	== LNAV ==		== LNAV ==

Natalia.Castrillo at 09:50, 28 January 2026

2026-01-28T09:50:08Z

← Older revision		Revision as of 09:50, 28 January 2026
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	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	}}		}}
	~~Every~~ satellite ~~receives from~~ the ~~ground antennas~~ the navigation data ~~which~~ is ~~sent back~~ to the ~~users~~ through ~~the navigation message~~.		The GPS monitor stations continuously track each satellite in GPS constellation to estimate its precise orbit and clock errors, then the Master Control Station uses those solutions to generate the GPS navigation messages. These data is uploaded to the GPS satellites through S-band ground antennas during passes and stored onboard. The satellites then rebroadcast the message to users on the L-band navigation signals (L1/L2/L5).
	The ~~Navigation Message provides all~~ the ~~necessary information~~ to allow the user to perform the positioning service. It includes the Ephemeris parameters, needed to compute the satellite coordinates with enough accuracy, the Time parameters and Clock Corrections, to compute satellite clock offsets and time conversions, the Service Parameters with satellite health information (used to identify the navigation data set), Ionospheric parameters model needed for single frequency receivers, and the Almanacs, allowing the computation of the position of ”all satellites in the constellation”, with a reduced accuracy (~~1 - 2 km of 1-sigma error~~)~~, which is needed for the acquisition of the signal by the receiver. The ephemeris and clocks parameters are usually updated every two hours, while the almanac is updated at least every six days~~.

	~~Besides~~ the ~~"legacy" L1 C/A~~ navigation message, ~~four additional new messages have been introduced by~~ the ~~so called GPS modernisation: L2-CNAV~~, ~~CNAV-2~~, ~~L5-CNAV and MNAV. The "legacy" message~~ and the ~~first three of the modernised GPS are civil messages~~, ~~while~~ the ~~MNAV is a military message. In modernised GPS,~~ the ~~same type~~ of ~~contents as~~ the ~~legacy navigation message~~ (~~NAV~~) ~~is transmitted but at higher rate and with improved robustness~~.		The navigation message provides all the necessary information to allow the user to perform the positioning service. As a minimum, each GPS navigation message includes the ephemeris parameters, needed to compute the satellite coordinates with enough accuracy; the time parameters and satellite clock corrections, to compute satellite clock offsets and time conversions; service parameters such as satellite health flags; ionospheric parameters, used by single frequency receivers; and the almanacs, which allow the computation of the position of "all satellites in the constellation" with a reduced accuracy (1 - 2 km of 1-sigma error) in order to support receiver signal acquisition.

	~~The messages L2-CNAV~~, ~~L5-CNAV and MNAV have a similar structure and (modernised)~~ data ~~format. The new format allows more flexibility~~, ~~better control and improved content. Furthermore, the MNAV includes new improvements for the security and robustness~~ of ~~the military message~~.		Under nominal conditions, the GPS Control Segment uploads new ephemeris data approximately every two hours, with longer intervals of six hours or more during non-nominal conditions. The almanac changes much more slowly, being updated at least every six days but usually refreshed daily.
	The ~~CNAV-2 is modulated onto L1C~~, ~~sharing the same band as the "legacy" navigation message~~.

	~~Further information on~~ the ~~different~~ navigation messages ~~can be found in~~ the ~~respective~~ GPS ~~Interface Control Documents (ICD) in [https~~:~~//archive~~.~~gps~~.~~gov/technical/icwg/~~ GPS ~~Official Website]~~.		Besides the "legacy" L1 C/A navigation message (LNAV), four additional new messages were introduced during the so called GPS modernisation: L2-CNAV, CNAV-2, L5-CNAV and MNAV. The LNAV, L2-CNAV, CNAV-2, L5-CNAV are civil messages, while the MNAV is a military message. In modernised GPS, the same type of contents as the legacy navigation message (NAV) is transmitted but at higher rate and with improved robustness.

	~~== L1 C/A ==~~		The messages L2-CNAV, L5-CNAV and MNAV have a similar structure and data format which allows more flexibility, better control and improved content. The MNAV includes new improvements for the security and robustness of the military message.
			The CNAV-2 is modulated onto L1C signal, sharing the same band as the "legacy" LNAV navigation message.

	The current “legacy” Navigation Message (~~NAV~~) is modulated on both carriers at 50 bps. The whole message contains 25 pages (or ~~’frames’~~) of 30 seconds each, forming the master frame that takes 12,5 minutes to be transmitted. Every frame is subdivided into 5 sub-frames of 6 seconds each; in turn, every sub-frame consists of 10 words, with 30 bits per word (see figure 3).		Further information on the different navigation messages can be found in the respective GPS Interface Control Documents (ICD) available at [https://archive.gps.gov/technical/icwg/ GPS Official Website]<ref name="GPS GOV Webpage">[https://archive.gps.gov/]</ref>.

			== LNAV ==

			The current “legacy” Navigation Message (LNAV) is modulated on both L1 C/A and L2 P(Y) carriers at 50 bps. The whole message contains 25 pages (or "frames") of 30 seconds each, forming the master frame that takes 12,5 minutes to be transmitted. Every frame is subdivided into 5 sub-frames of 6 seconds each; in turn, every sub-frame consists of 10 words, with 30 bits per word (see figure 3).
	Every sub-frame always starts with the telemetry word (TLM), which is necessary for synchronism. Next, the transference word (HOW) appears. This word provides time information (seconds of the GPS week), allowing the receiver to acquire the week-long P(Y)-code segment.		Every sub-frame always starts with the telemetry word (TLM), which is necessary for synchronism. Next, the transference word (HOW) appears. This word provides time information (seconds of the GPS week), allowing the receiver to acquire the week-long P(Y)-code segment.

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	The content of sub-frames 4 and 5 is common for all satellites. Thence, the almanac data for all in orbit satellites can be obtained from a single tracked satellite.		The content of sub-frames 4 and 5 is common for all satellites. Thence, the almanac data for all in orbit satellites can be obtained from a single tracked satellite.

	Further information can be found in IS-GPS-200 ICD document <ref name="GPS 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision L, "Navstar GPS Space Segment/User Segment Interfaces"]</ref>.		Further information on the LNAV message can be found in IS-GPS-200 ICD document <ref name="GPS ICD 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision N, "Navstar GPS Space Segment/Navigation User Segment Interfaces"]</ref>.

	== L2-CNAV ==		== L2-CNAV ==
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	Broadcast of messages is completely arbitrary, but sequenced to provide optimum user performance.		Broadcast of messages is completely arbitrary, but sequenced to provide optimum user performance.

	Further information can be found in IS-GPS-200 ICD document <ref name="GPS 200"></ref>.		Further information on the L2-CNAV message can be found in IS-GPS-200 ICD document <ref name="GPS ICD 200"></ref>.

	== L5-CNAV ==		== L5-CNAV ==
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	As in L2-CNAV, it is possible to define up to 63 different message types, but currently only the messages types 10-14 and 30-37 are defined. The remaining undefined and unused message types are reserved for future use.		As in L2-CNAV, it is possible to define up to 63 different message types, but currently only the messages types 10-14 and 30-37 are defined. The remaining undefined and unused message types are reserved for future use.

	Further information can be found in IS-GPS-705 ICD document <ref name="GPS 705">[https://archive.gps.gov/technical/icwg/IS-GPS-705J.pdf GPS ICD-705 Revision G, "Navstar GPS Space Segment/User Segment L5 Interfaces"]</ref>.		Further information on L5-CNAV message can be found in IS-GPS-705 ICD document <ref name="GPS ICD 705">[https://archive.gps.gov/technical/icwg/IS-GPS-705J.pdf GPS ICD-705 Revision J, "Navstar GPS Space Segment/User Segment L5 Interfaces"]</ref>.

	== CNAV-2 ==		== CNAV-2 ==
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	[[File:Cnav-2.png\|none\|thumb\|450px\|alt=Cnav-2\|'''''Figure 4:''''' CNAV-2 Navigation message]]		[[File:Cnav-2.png\|none\|thumb\|450px\|alt=Cnav-2\|'''''Figure 4:''''' CNAV-2 Navigation message]]

	Further information can be found in IS-GPS-800 ICD document <ref name="GPS 800">[https://archive.gps.gov/technical/icwg/IS-GPS-800J.pdf GPS ICD-800 Revision G, "Navstar GPS Space Segment/User Segment L1C Interfaces"].</ref>.		Further information on CNAV-2 message can be found in IS-GPS-800 ICD document <ref name="GPS ICD 800">[https://archive.gps.gov/technical/icwg/IS-GPS-800J.pdf GPS ICD-800 Revision J, "Navstar GPS Space Segment/User Segment L1C Interfaces"].</ref>.

	==References==		==References==
	<references/>		<references/>
	* [https://archive.gps.gov/technical/ps/1995-SPS-signal-specification.pdf DoD, USA, 1995] Global Positioning System Standard Positioning Service Performance Standard.
	* [https://archive.gps.gov/technical/ps/2007-PPS-performance-standard.pdf DoD, USA, 2007] Global Positioning System Precise Positioning Service Performance Standard.
	* [https://archive.gps.gov/technical/ps/2008-SPS-performance-standard.pdf DoD, USA, 2008] Global Positioning System Standard Positioning Service Performance Standard.
	* [https://archive.gps.gov/technical/icwg/IS-GPS-200D.pdf GPS Joint Program Office, 2004] Navstar GPS Space Segment / Navigation User Interfaces (IS-GPS-200D).
	* Mc Donald, K. and Hegarty, C., 2000. Modernization GPS Performance Capabilities. In: Proceedings of ION 56th Annual Meeting, 25-26 June 2000, San Diego California USA, pp. 242-249.

Gema.Cueto: Fixed references links

2026-01-25T11:36:20Z

Fixed references links

← Older revision		Revision as of 11:36, 25 January 2026
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	The CNAV-2 is modulated onto L1C, sharing the same band as the "legacy" navigation message.		The CNAV-2 is modulated onto L1C, sharing the same band as the "legacy" navigation message.

	Further information on the different navigation messages can be found in the respective GPS Interface Control Documents (ICD) in [https://~~www~~.gps.gov/technical/icwg/ GPS Official Website].		Further information on the different navigation messages can be found in the respective GPS Interface Control Documents (ICD) in [https://archive.gps.gov/technical/icwg/ GPS Official Website].

	== L1 C/A ==		== L1 C/A ==
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	The content of sub-frames 4 and 5 is common for all satellites. Thence, the almanac data for all in orbit satellites can be obtained from a single tracked satellite.		The content of sub-frames 4 and 5 is common for all satellites. Thence, the almanac data for all in orbit satellites can be obtained from a single tracked satellite.

	Further information can be found in IS-GPS-200 ICD document <ref name="GPS 200">[https://~~www~~.gps.gov/technical/icwg/IS-GPS-~~200L~~.pdf GPS ICD-200 Revision L, "Navstar GPS Space Segment/User Segment Interfaces"]</ref>.		Further information can be found in IS-GPS-200 ICD document <ref name="GPS 200">[https://archive.gps.gov/technical/icwg/IS-GPS-200N.pdf GPS ICD-200 Revision L, "Navstar GPS Space Segment/User Segment Interfaces"]</ref>.

	== L2-CNAV ==		== L2-CNAV ==
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	As in L2-CNAV, it is possible to define up to 63 different message types, but currently only the messages types 10-14 and 30-37 are defined. The remaining undefined and unused message types are reserved for future use.		As in L2-CNAV, it is possible to define up to 63 different message types, but currently only the messages types 10-14 and 30-37 are defined. The remaining undefined and unused message types are reserved for future use.

	Further information can be found in IS-GPS-705 ICD document <ref name="GPS 705">[https://~~www~~.gps.gov/technical/icwg/IS-GPS-~~705G~~.pdf GPS ICD-705 Revision G, "Navstar GPS Space Segment/User Segment L5 Interfaces"]</ref>.		Further information can be found in IS-GPS-705 ICD document <ref name="GPS 705">[https://archive.gps.gov/technical/icwg/IS-GPS-705J.pdf GPS ICD-705 Revision G, "Navstar GPS Space Segment/User Segment L5 Interfaces"]</ref>.

	== CNAV-2 ==		== CNAV-2 ==
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	[[File:Cnav-2.png\|none\|thumb\|450px\|alt=Cnav-2\|'''''Figure 4:''''' CNAV-2 Navigation message]]		[[File:Cnav-2.png\|none\|thumb\|450px\|alt=Cnav-2\|'''''Figure 4:''''' CNAV-2 Navigation message]]

	Further information can be found in IS-GPS-800 ICD document <ref name="GPS 800">[https://~~www~~.gps.gov/technical/icwg/IS-GPS-~~800G~~.pdf GPS ICD-800 Revision G, "Navstar GPS Space Segment/User Segment L1C Interfaces"].</ref>.		Further information can be found in IS-GPS-800 ICD document <ref name="GPS 800">[https://archive.gps.gov/technical/icwg/IS-GPS-800J.pdf GPS ICD-800 Revision G, "Navstar GPS Space Segment/User Segment L1C Interfaces"].</ref>.

	==References==		==References==
	<references/>		<references/>
	* [~~http~~://~~www~~.~~navcen.uscg~~.gov/~~pubs~~/~~gps~~/~~sigspec/gpssps1~~.pdf DoD, USA, 1995] Global Positioning System Standard Positioning Service Performance Standard.		* [https://archive.gps.gov/technical/ps/1995-SPS-signal-specification.pdf DoD, USA, 1995] Global Positioning System Standard Positioning Service Performance Standard.
	* [~~http~~://~~www~~.gps.gov/technical/ps/2007-PPS-performance-standard.pdf DoD, USA, 2007] Global Positioning System Precise Positioning Service Performance Standard.		* [https://archive.gps.gov/technical/ps/2007-PPS-performance-standard.pdf DoD, USA, 2007] Global Positioning System Precise Positioning Service Performance Standard.
	* [~~http~~://~~www~~.gps.gov/technical/ps/2008-SPS-performance-standard.pdf DoD, USA, 2008] Global Positioning System Standard Positioning Service Performance Standard.		* [https://archive.gps.gov/technical/ps/2008-SPS-performance-standard.pdf DoD, USA, 2008] Global Positioning System Standard Positioning Service Performance Standard.
	* [~~http~~://~~www~~.gps.gov/technical/icwg/IS-GPS-200D.pdf GPS Joint Program Office, 2004] Navstar GPS Space Segment / Navigation User Interfaces (IS-GPS-200D).		* [https://archive.gps.gov/technical/icwg/IS-GPS-200D.pdf GPS Joint Program Office, 2004] Navstar GPS Space Segment / Navigation User Interfaces (IS-GPS-200D).
	* Mc Donald, K. and Hegarty, C., 2000. Modernization GPS Performance Capabilities. In: Proceedings of ION 56th Annual Meeting, 25-26 June 2000, San Diego California USA, pp. 242-249.		* Mc Donald, K. and Hegarty, C., 2000. Modernization GPS Performance Capabilities. In: Proceedings of ION 56th Annual Meeting, 25-26 June 2000, San Diego California USA, pp. 242-249.

Gema.Cueto: /* L1 C/A */

2021-01-29T12:14:02Z

L1 C/A

← Older revision		Revision as of 12:14, 29 January 2021
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	* Sub-frame 1: contains information about the parameters to be applied to satellite clock status for its correction. These values are polynomial coefficients that allow converting time on board to GPS time. It also has information about satellite health condition.		* Sub-frame 1: contains information about the parameters to be applied to satellite clock status for its correction. These values are polynomial coefficients that allow converting time on board to GPS time. It also has information about satellite health condition.
	* Sub-frames 2 and 3: these sub-frames contain satellite ephemeris.		* Sub-frames 2 and 3: these sub-frames contain satellite ephemeris.
	* Sub-frame 4: provides ionospheric model parameters (in order to adjust for ionospheric refraction), UTC information (Universal Coordinate Time), part of the almanac, and indications whether the Anti-Spoofing, A/S, is activated or not (which transforms P code into the ~~[[GNSS Authentication and encryption \|~~ encrypted]] Y code).		* Sub-frame 4: provides ionospheric model parameters (in order to adjust for ionospheric refraction), UTC information (Universal Coordinate Time), part of the almanac, and indications whether the Anti-Spoofing, A/S, is activated or not (which transforms P code into the encrypted Y code).
	* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.		* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.
	Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.		Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.

Gema.Cueto: /* L1 C/A */

2021-01-29T11:51:01Z

L1 C/A

← Older revision		Revision as of 11:51, 29 January 2021
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	* Sub-frame 1: contains information about the parameters to be applied to satellite clock status for its correction. These values are polynomial coefficients that allow converting time on board to GPS time. It also has information about satellite health condition.		* Sub-frame 1: contains information about the parameters to be applied to satellite clock status for its correction. These values are polynomial coefficients that allow converting time on board to GPS time. It also has information about satellite health condition.
	* Sub-frames 2 and 3: these sub-frames contain satellite ephemeris.		* Sub-frames 2 and 3: these sub-frames contain satellite ephemeris.
	* Sub-frame 4: provides ionospheric model parameters (in order to adjust for ionospheric refraction), UTC information (Universal Coordinate Time), part of the almanac, and indications whether the Anti-Spoofing, A/S, is activated or not (which transforms P code into the encrypted Y code).		* Sub-frame 4: provides ionospheric model parameters (in order to adjust for ionospheric refraction), UTC information (Universal Coordinate Time), part of the almanac, and indications whether the Anti-Spoofing, A/S, is activated or not (which transforms P code into the [[GNSS Authentication and encryption \| encrypted]] Y code).
	* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.		* Sub-frame 5: contains data from the almanac and the constellation status. It allows to quickly identify the satellite from which the signal comes. A total of 25 frames are needed to complete the almanac.
	Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.		Sub-frames 1, 2 and 3 are transmitted with each frame (i.e., they are repeated every 30 seconds). Sub-frames 4 and 5 contain different pages (25 pages each) of the navigation message (see figure 1). Thence, the transmission of the full navigation message takes 25 × 30 seconds = 12.5 minutes.

Gema.Cueto: /* L5-CNAV */

2020-12-14T08:53:57Z

L5-CNAV

← Older revision		Revision as of 08:53, 14 December 2020
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	As in L2-CNAV, it is possible to define up to 63 different message types, but currently only the messages types 10-14 and 30-37 are defined. The remaining undefined and unused message types are reserved for future use.		As in L2-CNAV, it is possible to define up to 63 different message types, but currently only the messages types 10-14 and 30-37 are defined. The remaining undefined and unused message types are reserved for future use.

	Further information can be found in IS-GPS-705 ICD document <ref name="GPS 705">[https://www.gps.gov/technical/icwg/IS-GPS-705G.pdf ~~Interface Specification IS-~~GPS-705, Revision G]</ref>.		Further information can be found in IS-GPS-705 ICD document <ref name="GPS 705">[https://www.gps.gov/technical/icwg/IS-GPS-705G.pdf GPS ICD-705 Revision G, "Navstar GPS Space Segment/User Segment L5 Interfaces"]</ref>.

	== CNAV-2 ==		== CNAV-2 ==

Gema.Cueto at 08:50, 14 December 2020

2020-12-14T08:50:56Z

← Older revision		Revision as of 08:50, 14 December 2020
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	The content of sub-frames 4 and 5 is common for all satellites. Thence, the almanac data for all in orbit satellites can be obtained from a single tracked satellite.		The content of sub-frames 4 and 5 is common for all satellites. Thence, the almanac data for all in orbit satellites can be obtained from a single tracked satellite.

	Further information can be found in IS-GPS-200 ICD document <ref name="GPS 200">[https://www.gps.gov/technical/icwg/IS-GPS-200L.pdf ~~Interface Specification IS-~~GPS-200, Revision L]</ref>.		Further information can be found in IS-GPS-200 ICD document <ref name="GPS 200">[https://www.gps.gov/technical/icwg/IS-GPS-200L.pdf GPS ICD-200 Revision L, "Navstar GPS Space Segment/User Segment Interfaces"]</ref>.

	== L2-CNAV ==		== L2-CNAV ==

Gema.Cueto: /* CNAV-2 */

2020-12-14T08:49:19Z

CNAV-2

← Older revision		Revision as of 08:49, 14 December 2020
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	[[File:Cnav-2.png\|none\|thumb\|450px\|alt=Cnav-2\|'''''Figure 4:''''' CNAV-2 Navigation message]]		[[File:Cnav-2.png\|none\|thumb\|450px\|alt=Cnav-2\|'''''Figure 4:''''' CNAV-2 Navigation message]]

	Further information can be found in IS-GPS-800 ICD document <ref name="GPS 800">[https://www.gps.gov/technical/icwg/IS-GPS-800G.pdf GPS ICD-800 Revision G, "Navstar GPS Space Segment/User Segment L1C Interfaces".</ref>.		Further information can be found in IS-GPS-800 ICD document <ref name="GPS 800">[https://www.gps.gov/technical/icwg/IS-GPS-800G.pdf GPS ICD-800 Revision G, "Navstar GPS Space Segment/User Segment L1C Interfaces"].</ref>.

	==References==		==References==