Julian Date - Revision history

Gema.Cueto at 06:30, 11 September 2023

2023-09-11T06:30:25Z

← Older revision		Revision as of 06:30, 11 September 2023
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	The conversion between calendar year(Y)-month(M)-day(D)-UT and Julian dates is given by the following expressions [Hofmann-Wellenhof et al., 2008] <ref> [Hofmann-Wellenhof et al., 2008] Hofmann-Wellenhof, B., Lichtenegger, H., K. and Wasle, E., 2008. GNSS - Global Navigation Satellite Systems.. Springer-Verlag, Wien, Austria.</ref>, however this is a simplification of a general expression only valid from ~~a period starting in~~ March 1900 ~~until~~ February 2100:		The conversion between calendar year(Y)-month(M)-day(D)-UT and Julian dates is given by the following expressions [Hofmann-Wellenhof et al., 2008] <ref> [Hofmann-Wellenhof et al., 2008] Hofmann-Wellenhof, B., Lichtenegger, H., K. and Wasle, E., 2008. GNSS - Global Navigation Satellite Systems.. Springer-Verlag, Wien, Austria.</ref>, however this is a simplification of a general expression only valid for the time period from March 1900 to February 2100:

	:<math>		:<math>

Gema.Cueto at 06:28, 11 September 2023

2023-09-11T06:28:48Z

← Older revision		Revision as of 06:28, 11 September 2023
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	The conversion between calendar year(Y)-month(M)-day(D)-UT and Julian dates is given by the following expressions [Hofmann-Wellenhof et al., 2008] <ref> [Hofmann-Wellenhof et al., 2008] Hofmann-Wellenhof, B., Lichtenegger, H., K. and Wasle, E., 2008. GNSS - Global Navigation Satellite Systems.. Springer-Verlag, Wien, Austria.</ref>:		The conversion between calendar year(Y)-month(M)-day(D)-UT and Julian dates is given by the following expressions [Hofmann-Wellenhof et al., 2008] <ref> [Hofmann-Wellenhof et al., 2008] Hofmann-Wellenhof, B., Lichtenegger, H., K. and Wasle, E., 2008. GNSS - Global Navigation Satellite Systems.. Springer-Verlag, Wien, Austria.</ref>, however this is a simplification of a general expression only valid from a period starting in March 1900 until February 2100:

	:<math>		:<math>

Carlos.Lopez at 11:34, 23 February 2012

2012-02-23T11:34:02Z

← Older revision		Revision as of 11:34, 23 February 2012
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	\|Level=Intermediate		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011
	~~\|Logo=gAGE~~
	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	}}		}}

Jaume.Sanz at 10:09, 24 January 2012

2012-01-24T10:09:31Z

← Older revision		Revision as of 10:09, 24 January 2012
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	{{Article Infobox2		{{Article Infobox2
	\|Category=Fundamentals		\|Category=Fundamentals
	\|Authors=J. Sanz Subirana, JM. Juan Zornoza and M. ~~Hernandez~~-Pajares, University of ~~Catalunia~~, Spain.		\|Authors=J. Sanz Subirana, J.M. Juan Zornoza and M. Hernández-Pajares, Technical University of Catalonia, Spain.
	\|Level=Intermediate		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011

Jaume.Sanz at 10:08, 24 January 2012

2012-01-24T10:08:57Z

← Older revision		Revision as of 10:08, 24 January 2012
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	{{Article Infobox2		{{Article Infobox2
	\|Category=Fundamentals		\|Category=Fundamentals
	~~\|Title={{PAGENAME}}~~		\|Authors=J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain.
	\|Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain.
	\|Level=Intermediate		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011
	\|Logo=gAGE		\|Logo=gAGE
			\|Title={{PAGENAME}}
	}}		}}

	In order to facilitate calculations for long time intervals, the Julian Date (JD) is used (from Julio Scalier).		In order to facilitate calculations for long time intervals, the Julian Date (JD) is used (from Julio Scalier).

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	where <math>int</math> and <math>frac</math> ~~denotes~~ the integer and the fractional part of a real number.		where <math>int</math> and <math>frac</math> denote the integer and the fractional part of a real number.

Timo.Kouwenhoven: Text replace - "|Level=Medium" to "|Level=Intermediate"

2011-11-06T07:43:14Z

Text replace - "|Level=Medium" to "|Level=Intermediate"

← Older revision		Revision as of 07:43, 6 November 2011
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	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	\|Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain.		\|Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain.
	\|Level=~~Medium~~		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011
	\|Logo=gAGE		\|Logo=gAGE

Carlos.Lopez at 08:43, 9 August 2011

2011-08-09T08:43:12Z

← Older revision		Revision as of 08:43, 9 August 2011
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	[[Category:Fundamentals]]		[[Category:Fundamentals]]
			[[Category:GNSS Time Reference, Coordinate Frames and Orbits]]
			[[Category:Time Systems]]

Carlos.Lopez at 12:43, 8 August 2011

2011-08-08T12:43:19Z

← Older revision		Revision as of 12:43, 8 August 2011
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	e=int[\displaystyle\frac{b-d}{30.6001}]		e=int[\displaystyle\frac{b-d}{30.6001}]
	\end{array}		\end{array}
	\qquad \mbox{(2)}		\qquad \mbox{(3)}
	</math>		</math>

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	Y=c-4715-int[\displaystyle\frac{7+M}{10}]		Y=c-4715-int[\displaystyle\frac{7+M}{10}]
	\end{array}		\end{array}
	\qquad \mbox{(3)}		\qquad \mbox{(4)}
	</math>		</math>

Carlos.Lopez at 10:18, 27 July 2011

2011-07-27T10:18:08Z

← Older revision		Revision as of 10:18, 27 July 2011
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	:<math>		:<math>
	JD=int[365.25\; y]+int[30.6001\; (m+1)]+D+\frac{UT\_hours}{24.0}+1\,720\,981.5		JD=int[365.25\; y]+int[30.6001\; (m+1)]+D+\frac{UT\_hours}{24.0}+1\,720\,981.5
			\qquad \mbox{(1)}
	</math>		</math>

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	y=Y &\mbox{ and } m=M; & M>2;		y=Y &\mbox{ and } m=M; & M>2;
	\end{array}		\end{array}
	\qquad \mbox{(1)}		\qquad \mbox{(2)}
	</math>		</math>

Carlos.Lopez: Created page with "{{Article Infobox2 |Category=Fundamentals |Title={{PAGENAME}} |Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain. |Level=Medium..."

2011-07-27T10:17:22Z

Created page with "{{Article Infobox2 |Category=Fundamentals |Title={{PAGENAME}} |Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain. |Level=Medium..."

New page

{{Article Infobox2
|Category=Fundamentals
|Title={{PAGENAME}}
|Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain.
|Level=Medium
|YearOfPublication=2011
|Logo=gAGE
}}

In order to facilitate calculations for long time intervals, the Julian Date (JD) is used (from Julio Scalier).

The Julian Date defines the number of days <ref group="footnotes">Julian century is defined as <math>36\,525</math> days.</ref> elapsed since 4713 B.C., January <math>1^d_{\cdot}5</math> (i.e. 12<math>^{h}</math> of January 1st). This day is the zero epoch for the Julian Date and, after that time, the days are counted without interruption. Every Julian day begins at the <math>12</math> hours UT of the civil day and ends at the <math>12</math> hours UT of the following. This kind of calendar does not use the hour:minute:second format, but it uses fractions of day.

The conversion between calendar year(Y)-month(M)-day(D)-UT and Julian dates is given by the following expressions [Hofmann-Wellenhof et al., 2008] <ref> [Hofmann-Wellenhof et al., 2008] Hofmann-Wellenhof, B., Lichtenegger, H., K. and Wasle, E., 2008. GNSS - Global Navigation Satellite Systems.. Springer-Verlag, Wien, Austria.</ref>:

:<math>
JD=int[365.25\; y]+int[30.6001\; (m+1)]+D+\frac{UT\_hours}{24.0}+1\,720\,981.5
</math>

where:

:<math>
\begin{array}{lll}
y=Y-1 &\mbox{ and } m=M+12; & M\leq2 \\
y=Y &\mbox{ and } m=M; & M>2;
\end{array}
\qquad \mbox{(1)}
</math>

The JD relative to J2000 is obtained by subtracting <math>2\,451\,545.0</math> days to the JD (i.e., the number of days elapsed since 2000 January <math>1.5</math>-st).

The inverse transformation is carried out computing the next values:

:<math>
\begin{array}{l}
a=int[JD+0.5] \\[0.3cm]
b=a+1537 \\[0.3cm]
c=int[\displaystyle\frac{b-122.1}{365.25}] \\[0.3cm]
d=int[365.25\; c] \\[0.3cm]
e=int[\displaystyle\frac{b-d}{30.6001}]
\end{array}
\qquad \mbox{(2)}
</math>

Afterwards the civil date is obtained with the following expressions:

:<math>
\begin{array}{c}
D=b-d-int[30.6001\; e]+frac[JD+0.5] \\[0.3cm]
M=e-1-12\times int[\displaystyle\frac e{14}]\\[0.3cm]
Y=c-4715-int[\displaystyle\frac{7+M}{10}]
\end{array}
\qquad \mbox{(3)}
</math>

where <math>int</math> and <math>frac</math> denotes the integer and the fractional part of a real number.

==Notes==
<references group="footnotes"/>

==References==
<references/>

[[Category:Fundamentals]]