GPS Date Converter (GDC) is a program to convert six different date formats, including:
(1) Decimal year, (2) Year, Month, Day, (3) Year, Day of year, (4) GPS Week, Day of week, (5) Julian date, and (6) Modified Julian date. These formats are quiet common in Earth Sciences, specially GPS applications. More information can be found in the GDC website.
gpsdateconv works perfectly, thanks