[time-nuts] GPRS zero azimuth and elevation, most PRN displayed as not O/K,
Mark C. Stephens
marks at non-stop.com.au
Wed Jun 26 23:02:18 EDT 2013
I miss-advertently restarted the GPSR-A due to the after effects of a liquid lunch..
and about 30 minutes later:
E-113>:syst:stat?
[ Active ] -------------------- GPSR 2 Status --------------------------------
SYNCHRONIZATION ........................... [ Outputs Valid/Reduced Accuracy ]
SmartClock Mode _________________________ Reference OutPuts _______________
>> Locked to GPS TFOM 3 FFOM 0
Recovery 1PPS TI +400 ns
Holdover HOLD THR
Power-up Holdover Uncertainty_____________
Predict
ACQUISITION ............................................... [ GPS 1PPS Valid ]
Tracking: 8 Not Tracking: 4 Time ____________________________
PRN El Az C/N PRN El Az GPS 02:56:29 27 Jun 2013
3 25 228 50 15 Not OK GPS 1PPS Synchronized to GPS
6 42 239 49 16 Not OK ANT DLY 0 ns
14 21 349 51 24 Not OK Position ________________________
18 70 181 46 29 Not OK MODE Survey: 45.0% complete
19 0 0 48
21 62 109 52 AVG LAT S 33:45:49.292
22 54 268 50 AVG LON E 151:05:31.486
27 34 229 52 AVG HGT +112.91 m (MSL)
ELEV MASK 10 deg
HEALTH MONITOR ........................................................ [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK
Alarms: (none)
Now, Compared to a Z3805A for the same time, same place:
HEWLETT-PACKARD,Z3805A,3502A00508,3543B-A. Life count: 33099
SYNCHRONIZATION ............................................. [ Outputs Valid ]
SmartClock Mode ___________________________ Reference Outputs _______________
>> Locked to GPS TFOM 3 FFOM 0
Recovery 1PPS TI +3.0 ns relative to GPS
Holdover HOLD THR 1.000 us
Power-up Holdover Uncertainty ____________
Predict 1.3 us/initial 24 hrs
ACQUISITION ............................................ [ GPS 1PPS CLK Valid ]
Satellite Status __________________________ Time ____________________________
Tracking: 6 Not Tracking: 4 LOCAL 12:55:57 27 Jun 2013
PRN El Az SS PRN El Az 1PPS CLK Synchronized to UTC
6 49 276 94 3 36 252 ANT DLY 28 ns
14 47 347 86 15 13 137 Position ________________________
18 52 139 167 19 25 227 MODE Hold
21 46 71 130 24 18 103
22 65 218 184 LAT S 33:45:49.225
27 47 258 114 LON E 151:05:31.528
ELEV MASK 10 deg HGT +80.11 m (MSL)
HEALTH MONITOR ......................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK
Actually, A Z3815A might be better as it uses c/n
HEWLETT-PACKARD,Z3815A,KR73503191,U-4010.0-A. Life count: 39166
[ Active ] --------------------- GPSR 2 Status --------------------------------
SYNCHRONIZATION ............................................. [ Outputs Valid ]
SmartClock Mode ___________________________ Reference Outputs _______________
>> Locked to GPS TFOM 3 FFOM 0
Recovery 1PPS TI +12.0 ns relative to GPS
Holdover HOLD THR 1.000 us
Power-up Holdover Uncertainty ____________
Predict: 1.5 us/initial 24 hrs
ACQUISITION ................................................ [ GPS 1PPS Valid ]
Tracking: 8 ____ Not Tracking: 2 ________ Time ____________________________
PRN El Az C/N PRN El Az LOCAL 12:57:40 27 Jun 2013
3 36 252 50 19 25 227 GPS 1PPS Synchronized to UTC
6 48 277 49 24 18 103 ANT DLY 28 ns
14 48 347 47 Position ________________________
15 12 138 44 MODE Hold
18 52 139 47
21 46 71 47 LAT S 33:45:49.500
22 65 217 47 LON E 151:05:31.734
27 47 258 50 HGT +95.40 m (MSL)
ELEV MASK 10 deg
HEALTH MONITOR ......................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK
Alarms: (none)
Hmm, the Z3815A Holdover predicted uncertainty is usually down around 100-400ns but it's particularly rainy, cloudy and stormy today, here.
But the c/n are roughly the same so I guess the front end of the GPS module is o/k.
All the Receivers are fed off the same splitter so it's not an antenna issue.
I must mention I took your advice and did a syst:pres last night which seems to have made it behave slightly better.
But look at the PPS offset. 400ns is not good.
I think the GPS module is possibly a bit wacky (I mean off frequency or something, dunno).
That could also explain why it has difficulties in calculating the position of the satellites.
It's looks like a standard Motorola UT RX but with the battery add on.
I checked the battery and its 3v.
I think I'll let the survey complete and if it's still wonky I'll drop another Moto receiver in and see what happens,
I mean what's the worst thing that could happen, the GPSDO could change the firmware on the module to 3.2 or something ;)
But anyway, Let's see what happens at the end of survey.
-marki
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Azelio Boriani
Sent: Thursday, 27 June 2013 2:37 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPRS zero azimuth and elevation, most PRN displayed as not O/K,
12 minutes are enough to receive the data... another strange thing is that you have the 1PPS TI always 0. Have you already given the :SYST:PRES command to preset the receiver to the factory settings?
On Wed, Jun 26, 2013 at 6:13 PM, Mark C. Stephens <marks at non-stop.com.au> wrote:
> Hi Azelio, err...
>
>
> E-113>:syst:stat?
> [ Unlocked ] ------------------ GPSR 2 Status
> -------------------------------- SYNCHRONIZATION ........................... [ Outputs Valid/Reduced Accuracy ]
> SmartClock Mode _________________________ Reference OutPuts _______________
> Locked to GPS TFOM 3 FFOM 3
> Recovery 1PPS TI +0 ns
> Holdover HOLD THR
>>> Power-up: OCXO Warm-up Holdover Uncertainty_____________
> Predict
>
> ACQUISITION ............................................... [ GPS 1PPS Valid ]
> Tracking: 6 Not Tracking: 0 Time ____________________________
> PRN El Az C/N PRN El Az LOCL GPS 02:10:05 27 Jun 2013
> 7 0 0 39 GPS 1PPS Synchronized to GPS
> 8 0 0 50 ANT DLY 28 ns
> 9 0 0 52 Position ________________________
> 15 0 0 44 MODE Survey: 1.3% complete
> 17 0 0 49
> 24 0 0 39 AVG LAT S 33:45:49.689
> AVG LON E 151:05:31.705
> AVG HGT +131.66 m (MSL)
> ELEV MASK 10 deg
> HEALTH MONITOR ........................................................ [ OK ]
> Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK
> Alarms: (none)
>
>
>
>
> They are all zero now!
> I have just changed eman to 10 and rebooted.
> I guess it must be something to do with almanac, perhaps being patient
> and waiting a day or 3 may yield a change.
> Hopefully for the better.
>
>
> marki
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
> On Behalf Of Azelio Boriani
> Sent: Wednesday, 26 June 2013 7:09 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPRS zero azimuth and elevation, most PRN
> displayed as not O/K,
>
> Try to put the elevation mask to 10degrees, not 25 :GPS:SAT:TRAC:EMAN
> 10
>
> On Tue, Jun 25, 2013 at 8:41 AM, Mark C. Stephens <marks at non-stop.com.au> wrote:
>> I have a GPSR2 with unusual; GPS behaviour.
>>
>> E-113>:syst:stat?
>> [ Active ] -------------------- GPSR 2 Status
>> -------------------------------- SYNCHRONIZATION ........................... [ Outputs Valid/Reduced Accuracy ]
>> SmartClock Mode _________________________ Reference OutPuts _______________
>>>> Locked to GPS TFOM 3 FFOM 0
>> Recovery 1PPS TI +0 ns
>> Holdover HOLD THR
>> Power-up Holdover Uncertainty_____________
>> Predict
>>
>> ACQUISITION ............................................... [ GPS 1PPS Valid ]
>> Tracking: 5 Not Tracking: 7 Time ____________________________
>> PRN El Az C/N PRN El Az GPS 06:37:39 25 Jun 2013
>> 1 0 0 49 3 Not OK GPS 1PPS Synchronized to GPS
>> 11 0 0 47 6 Not OK ANT DLY 28 ns
>> 14 25 349 43 15 Not OK Position ________________________
>> 31 0 0 49 18 Not OK MODE Hold
>> 32 0 0 47 21 Not OK
>> 22 Not OK LAT S 33:45:49.374
>> 27 Not OK LOG E 151:05:31.495
>> HGT +118.61 m (MSL)
>> ELEV MASK 25 deg
>> HEALTH MONITOR ........................................................ [ OK ]
>> Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK
>> Alarms: (none)
>>
>>
>> As you can see the Azimuth and elevation are zero.
>>
>> Group opinion please, bad antenna connector or bad GPS module?
>>
>>
>> -marki
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