Current time from GPRMC or GPZDA?

Question

In GPRMC there is a time field, called fix time. Can I consider this always the same as value from GPZDA time? Is there any possibility that when GPS device is configured to stream both GPRMC and GPZDA sentences, but their value will be different?

For my task it would be great if I could get time from GPRMC, however, I'm not sure if I can get consistent time value from there.

Answer 1

GPRMC works

Sentence Example

$GPRMC,040302.663,A,3939.7,N,10506.6,W,0.27,358.86,200804,,*1A

GPS devices are able to calculate the current date and time using GPS satellites (and not the computer's own clock, making it useful for synchronization). This word stores the current time, in UTC, in a compressed form "HHMMSS.XXX," where HH represents hours, MM represents minutes, SS represents seconds, and XXX represents milliseconds. The above value represents 04:03:02.663 AM UTC.

http://www.codepedia.com/1/The+GPRMC+Sentence

GPZDA

Date & Time

UTC, day, month, year, and local time zone.

$--ZDA,hhmmss.ss,xx,xx,xxxx,xx,xx hhmmss.ss = UTC xx = Day, 01 to 31 xx = Month, 01 to 12 xxxx = Year xx = Local zone description, 00 to +/- 13 hours xx = Local zone minutes description (same sign as hours)

$GPGGA: Global Positioning System Fix Data
$GPGSV: GPS satellites in view
$GPGSA: GPS DOP and active satellites
$GPRMC: Recommended minimum specific GPS/Transit data 

http://playground.arduino.cc/Tutorials/GPS