how to transfer a time which was zero at year of 0000(maybe) to java.util.Date

I have a gps time in the database,and when I do some query,I have to use the java.util.Date,however I found that I do not know how to change the gps time to java.util.Date.

Here is a example:

The readable time   === The GPS time
2010-11-15 13:10:00 === 6342541920开发者_如何学编程00000000 
2010-11-15 14:10:00 === 634254228000000000

The period of the two date is "36000000000",,obviously it stands for one hour,so I think the unit of the gps time in the db must be nanosecond.

1 hour =3600 seconds= 3600*1000 milliseconds ==  3600*1000*10000 nanoseconds

Then I try to convert the gps time:

Take the " 634254228000000000" as example,it stands for("2010-11-15 14:10:00");

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ssZ");
Date d = new Date(63425422800000L);
System.out.println(sdf.format(d));

The result is

3979-11-15 13:00:00+0000.

Of course it is wrong,then I try to calculate :

63425422800000/3600000/24/365=2011.xxx

So it seems that the gps time here is not calcuated from Epoch(1970-01-01 00:00:00+0000). It maybe something like (0001-01-01 00:00:00+0000).

Then I try to use the following method:

Date date_0=sdf.parse("0001-01-01 00:00:00+0000");
Date d = new Date(63425422800000L);
System.out.println(sdf.format(d.getTime() + date_0.getTime()));

The result is:
2010-11-13 13:00:00+0000. :(

Now I am confusing about how to calculate this gps time.

Any suggestion?

1 millisecond = 1 000 000 nanoseconds

so... 1 hour =3600 seconds= 3600*1000 milliseconds == 3600*1000*10000000 nanoseconds

Notice that GPS time is 15 seconds ahead from UTC : gps-time-representation-library

There are other time and date systems as well; for example, the time scale used by the satellite-based global positioning system (GPS) is synchronized to UTC but is not adjusted for leap seconds.

Quoted from : Java Util Date API

GPS time was zero at 6-Jan-1980 as opposed to Epoch which was zero at 1970-01-01 00:00:00+0000

Here is the simple Java code I used to convert GPS time (ms) to Java Date:

BigInteger gpsTime = new BigInteger("973865400000");
GregorianCalendar calendar = 
                      new GregorianCalendar(1980, Calendar.JANUARY, 6, 0, 0, 0);
long gpsDiff = calendar.getTimeInMillis(); // gps offset to a   
Date javaDate = new Date(gpsDiff + gpsTime.longValue());
System.out.println("Java Date: " + javaDate);
// prints: Java Date: Mon Nov 15 14:10:00 EST 2010