[time-nuts] new gps sat prn30 svn64

tom jones epoch_time at yahoo.com
Sat Feb 22 13:16:54 EST 2014


svn64 alive and well

Using sirfdemo pc software coupled with sirf iv gps receiver I picked up the first signal from svn64 (now assigned prn30).
The sat was launched from cape canavral (airforce station) florida last thursday evening 2-20-14 about 17:55pdt.
The gps control people seem to be turning on the satellites transmitter intermittantly.
The new satellite will not be in its final orbit for approximately 30 days and not usable till about 36 days from its launch 

date.

My first reception was at 23:32:22pdt

gps time error		freq-drift	   date	     time pdt

4.4716290517e-010,-1.1166002510e-014	@ 02/21/2014 23:32:22
2.7434175598e-010,-5.1373205549e-014	@ 02/22/2014 00:57:22
2.7264644019e-010,-5.1373205549e-014	@ 02/22/2014 00:57:52
2.7202887741e-010,-5.2401886405e-014	@ 02/22/2014 00:58:22
2.7003760573e-010,-5.2401886405e-014	@ 02/22/2014 00:58:52
2.6877996045e-010,-5.2401886405e-014	@ 02/22/2014 00:59:22
2.6416859445e-010,-5.2401886405e-014	@ 02/22/2014 01:00:52
2.5693992947e-010,-5.3422655975e-014	@ 02/22/2014 01:02:52
2.5624543494e-010,-5.3422655975e-014	@ 02/22/2014 01:03:22
2.5421537401e-010,-5.3422655975e-014	@ 02/22/2014 01:03:52
2.4365104104e-010,-5.4384875238e-014	@ 02/22/2014 01:06:52
2.4196987886e-010,-5.5335398671e-014	@ 02/22/2014 01:07:22
2.3208415713e-010,-5.6217685129e-014	@ 02/22/2014 01:10:22
2.3084736806e-010,-5.6217685129e-014	@ 02/22/2014 01:10:52
2.1308972996e-010,-5.7062414147e-014	@ 02/22/2014 01:15:52
2.1229085616e-010,-5.7062414147e-014	@ 02/22/2014 01:16:22
2.1024898532e-010,-5.7873397372e-014	@ 02/22/2014 01:16:52
1.7422816710e-010,-6.0095673013e-014	@ 02/22/2014 01:26:52
1.4985197051e-010,-6.1364392842e-014	@ 02/22/2014 01:33:52
-8.2096225744e-011,-6.4458299267e-014	@ 02/22/2014 02:33:22
-8.7252889686e-011,-6.4458299267e-014	@ 02/22/2014 02:34:52
-8.8348680774e-011,-6.4458299267e-014	@ 02/22/2014 02:35:22
-1.0635115866e-010,-6.3795634899e-014	@ 02/22/2014 02:39:52
-1.0947714477e-010,-6.3795634899e-014	@ 02/22/2014 02:40:52
-1.2733387921e-010,-6.2957112939e-014	@ 02/22/2014 02:45:22

This is a complete list of all that was received from the new prn30 satellite (so far). perhaps there saving power till solar 

pannel deployment? or are saving power to charge batterys after just deploying solar pannels?

The numbers were cut an pasted from message id 30 (nl sv state data) from the sirfdemo pc software logging feature.
I've been monitoring this information for the last 8 weeks logging many days of satellite data.

It appears that gps time error gets updated from the satellite broadcast navagation message at least daily.
I believe that the gps receiver then computes the satellite frequency drift (including doppler shift) and computes gps time 

error till the next satellite navagation broadcast message updates the accumulated time error.

Atomic clocks in gps orbit run 45us fast perday due to less gravity but loose 8 us per day do to 
there high velocity. the net result is 37us per daily. 
 
It looks like the new satellite clock is keeping excellant time for not being in orbit yet.. perhaps it is allready high 

enough above earth to not experience the slower time of earths gravity?

The old Prn30 has been flagged unusable for years. but data was still received and logged with sirfdemo. 

This is the last data from the old satellite prn30 (norad number 34661) whose transmissions became intermittant the last week 

(control operators turning it off and on).

gps time error     frequency drift
6.7348954278e-004,2.8731554896e-012	@ 02/21/2014 11:21:28 = last intermittant message from the old prn30 satellite.

My gps receiver is a bu-353s4 (sirf-4) usb dongle that is available on ebay for about $40 dollars. My old sirfIII worked a 

little better (globalsat holux gr-213u). the new sirf IV spitts unwanted data randomly into log file. random data labeled 

unk:hexadecimal strings no help on internet but many complaints.. sirfdemo software is still downloadable from the internet.

Nothing else has been received sense 02:45. I dont know if the sat is still visable to the usa right now or if the 

transmissions have been disabled .. 
There isn't any information on the internet yet.. No norad satellite numbers (svn64) published for tracking it yet.

Enjoy. hope my tabs and spaces keep data aligned..




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