static double GetCumulativeLeapSeconds(double julianDate)
{
double leapSeconds = 0;
const double daysOffset = 2400000.5;
var leapSecondsArray = LeapSecondsArray.GetArray();
int length = leapSecondsArray.Length;
if (julianDate >= leapSecondsArray[0].JulianDate)
{
//Find the index in the lookup table which contains the JulianDate value closest to the JulianDate input parameter
bool isContinue = true;
int index = 1;
while (isContinue)
{
if (index >= length)
{
leapSeconds = leapSecondsArray[length - 1].Seconds
+ (julianDate - daysOffset - leapSecondsArray[length - 1].BaseModifiedJulian)
* leapSecondsArray[length - 1].Coefficient;
isContinue = false;
}
else if (julianDate < leapSecondsArray[index].JulianDate)
{
leapSeconds = leapSecondsArray[index - 1].Seconds
+ (julianDate - daysOffset - leapSecondsArray[index - 1].BaseModifiedJulian)
* leapSecondsArray[index - 1].Coefficient;
isContinue = false;
}
//Prepare for the next loop
if (isContinue)
{
++index;
}
}
}
return(leapSeconds);
}
public static double ConvertCoordinatedTime(double julianDate) // Convert from universal coordinated time (UTC) given as a two-part pseudo-Julian date to terrestrial time(TT), represented as a two-part Julian date.
{
//Outside of the range 1 January 1961 to 500 days after the last leap second,
// implement TT2UTC as TT2UT1
const int dayOffset = 500;
var leapSecondsArray = LeapSecondsArray.GetArray();
int length = leapSecondsArray.Length;
if ((julianDate < leapSecondsArray[0].JulianDate) || (julianDate > (leapSecondsArray[length - 1].JulianDate + dayOffset)))
{
return(ConvertUniversalTime(julianDate));
}
double deltaOfTime = GetDeltaOfTime(julianDate);
double leapSeconds = GetCumulativeLeapSeconds(julianDate);
const int secondsInDay = 86400;
const double secondsOffset = 32.184;
return
(julianDate
- ((deltaOfTime - leapSeconds - secondsOffset) / secondsInDay)
+ (deltaOfTime / secondsInDay));
}
