How to convert a number into a date

I have two sets of numbers (Representing same day of a GPS position time series),and I do not know the their types.I want to convert either of them and obtain the day/month/year. Type 1 ( 2017.23972602740 ) and Type 2 (52634).I tried datetime(x,'ConvertFrom','datenum') and datetime(x,'ConvertFrom','juliandate') but cannot obtain correct date. Please help.

[dpb]

See <gps/timsys.html> for the first.

AFAIK, TMW hasn't yet supplied a builtin conversion in datetime...

I don't recognize the second...

[TSR]

Hello dpb,

Thank you for the information,it helped me to figure out the Type 2 (52634) . It is modified julian date.Therefore,using datetime(x,'ConvertFrom','modifiedjuliandate') we can obtain the date in format of day/month/year

Answer 1

[Cris LaPierre]

Haven't figured out Type 1 yet, but based on this website, I think I've got a way to convert Type 2.

% GPS time
t = 52634;
tUnix = t+315964800;

dt = datetime(tUnix,"ConvertFrom","posixtime")

dt = 
   06-Jan-1980 14:37:14

[dpb]

I figured it had something like that, but haven't ever messed w/ any GPS stuff to have actual experience...

[TSR]

Hi Cris,

type two is in modified julian dates

date= datetime(52634,'ConvertFrom','modifiedjuliandate')

date = 

  datetime

   26-Dec-2002 00:00:00