perturb::DateTime Struct Reference

A basic and human readable representation of a point in time. More...

#include <perturb.hpp>

Public Attributes
int	year
	Year from 1900 to 2100.
int	month
	Month from 1 to 12.
int	day
	Day from 1 to {28, 29, 30, 31} (depending on month)
int	hour
	Hour from 0 to 23.
int	min
	Minute from 0 to 59.
double	sec
	Fractional seconds from 0.0 to 59.999...

Detailed Description

A basic and human readable representation of a point in time.

The primary purpose of this type is to be constructed manually via aggregate initialization and the converted to a JulianDate.

Warning

This type doesn't enforce a valid date and time upon construction; there are no checks. Additionally, the conversion to JulianDate values are only valid from years 1900 to 2100.

The question of what this time point represents gets complicated. In the "Revisiting Spacetrack Report #3" paper from Celestrak, it is discussed what this time represents. While UTC would make sense, the method perturb::sgp4::gstime_SGP4 requires UT1 time to calculate GMST. This library makes the same assumption that the paper concludes:

"The error associated with approximating UT1 with UTC is within the theoretical uncertainty of the SGP4 theory itself. Except for the GMST calculation, this paper and code assumes time to be realized as UTC."

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The documentation for this struct was generated from the following file:

• /github/workspace/include/perturb/perturb.hpp