[time-nuts] Preliminary list of GCRU-D Commands.

marks twotoe.com marks at twotoe.com
Fri May 16 19:22:35 EDT 2008


Here are the commands I have found on the Chong Ho aka Samsung GCRU-D GPSDO.

This is a very capable reference from the CDMA era.

The GPSDO uses a subset of the Symmetricom scpi commands.

Most interestingly there is a debug mode.

I will follow up with interfacing to the unit and modifications.

Please note this is the complete list of commands I could find, however I am still working on discovering syntax and meaning.

This information is so much more useful if it is shared.


*IDN?   ID
*TEST   SYSTEM Self Test 

:ALAR:EXTR?  not sure
:ALARM:HARD?  not sure
:ALAR:OPER?  not sure

:DIAG:INP:DATA?  not sure
:DIAG:LOG:READ? 1 Read the first diagnostic log entry
:DIAG:LOG:READ:ALL? Returns all of the most recent diagnostic log entries.
:DIAG:LOG:CLE  Clears the diagnostic log
:DIAG:LOG?  not sure
:DIAG:ROSC:EFC:ABS? Get absolute oscillator EFC setting
:DIAG:ROSC:EFC:REL? Returns the Electronic Frequency Control (EFC) output value of the internal reference oscillator.
:DIAG:ROSC:EFC?  not sure

:GPS:INIT:DATE  Enter the date (yr,mo,day)
:GPS:INIT:POS   Enter approx. position (N|S,deg,min,sec, E|W,deg,min,sec, elev. in meters)
:GPS:INIT:TIME   Enter the approximate time (hr,min,sec)
:GPS:POS  Enter position hold location (use N|S,deg,min,sec, E|W,deg,min,sec, elev. in meters or SURV for current surveyed position or LAST for last held position)
:GPS:POS?  Get GPS Position hold location
:GPS:POS:HOLD:LAST? returns the last position-hold setting, which is restored when the :GPS:POSition LAST command is sent.
:GPS:POS:HOLD:STAT? 0 indicates survey mode; a value of 1 indicates position hold.
:GPS:POS LAST  Cancel surveying and restore the last position setting
:GPS:POS SURVey  Directs the GPS to stop surveying and use the average of individual position computations.
:GPS:POS:SURV ONCE  Survey for location
:GPS:POS:SURV:PROG? Get Survey Progress
:GPS:POS:SURV:STAT ONCE Initiates survey mode during which the Receiver determines its position from satellite data.
:GPS:POS:SURV:POW not sure

:GPS:REF:ADEL  sets the GPS antenna delay value in seconds <float> <s | ns >
:GPS:REF:ADEL?  gets the GPS antenna delay value in seconds <float>

:GPS:SAT:TRAC:EMAN  Enter the elevation mask angle (0 to 89 in degrees)
:GPS:SAT:TRAC:EMAN? Get the elevation mask angle (0 to 89 in degrees)
:GPS:SAT:TRAC:COUN? returns number of tracked sats
:GPS:SAT:TRAC?  returns id of tracked sats


:PTIM:DATE?  Get current Date
:PTIM:FFOM?  not sure
:PTIM:LEAP?  not sure
:PTIM:LEAP:ACC?  Get accumulated leapseconds between GPS and UTC time
:PTIM:LEAP:STATE? not sure
:PTIM:TIME?  Get current Time
:PTIM:TZON   Use this to set time to your local time. Enter offset from UTC (use hr,min). Range is -12 to + 13 hours
:PTIM:TZON?  Get user-entered time offset from UTC


:SYNC:HOLD:INIT  Initiate manual holdover
:SYNC:HOLD:REC:INIT  Initiate recover from manual holdover
:SYNC:TINT?  Get GPS 1 PPS to Internal Osc 1 PPS interval

:OUTP:STAT?  active / standby reference
:OUTP:ACT:ENAB  not sure
:OUTP:ACT:DIS  not sure
:OUTP:ACTIVE  not sure
:OUTP:INACTIVE  not sure

:SYST:DATE?  Get current Date
:SYST:TIME?  Get current Time
:SYST:PON  reboot
:SYST:PRES  Reboot with fdactory defaults
:SYST:STAT?  status

:DBGCMD   changes to debug mode
BAUD   debug; change serial port speed [2400/4800/9600/19200/38400]
EVENERR   debug; Make Align Error
MSGERR   debug; Make Rcvr Message Handling Error to test even align error
MSGFAIL   debug; Make Rcvr Message Handling Fail
RESET   debug; reboot
DVER?   debug; bugged command. unknown.
rtctime   debug; returns rtc time
todbuf   debug; unsure
todmsg   debug; unsure
todcmd   debug; Change Debug Command Format to TOD Form and exits debug mode
addlog   debug; [SYNTAX] ADDLOG YYYYMMDDhhmmss string
warmup   debug; change warmup time in minutes eg WARMUP [min]
holdtcn   debug; Syntax to Change HoldOver Time : HOLDTCN [min]
editsl   debug; self learn [SYNTAX] EDITSL [ON/OFF]
slsave   debug; self learn SYNTAX : SLSAVE [ON]
initpll   debug; reset and initialise pll
hoffset   debug; save hold offset
aging   debug; unknown Hour Aging Offset
usrhold   debug; unknown Sec aging comp para
flock   debug; FLOCK {ALPHA/ERROR/DAC} {int}
alpha   debug; ALPHA Value Command Syntax ==> ALPHA {A/S} {F1/F2/N1/N2} {int} (f=fast mode, n=normal mode)
beta   debug; BETA Value Command Syntax ==> BETA {A/S} {F1/F2/N1/N2} {int} (f=fast mode, n=normal mode)
shift   debug; SHIFT Value Command Syntax ==> BETA {A/S} {F1/F2/N1/N2} {int} (f=fast mode, n=normal mode)
offset   debug; unknown
saveoffset  debug; unknown
savedac   debug save current Dac Value, 'SAVEDAC ON'
plltest   debug; unknown
plldis   debug; Pll Process Display {on/off}
pll10msdis  debug; display pll value every 10ms {on/off}
status   debug; short status display
pwralm   debug; unknown
block   debug; unknown
rcvrmsg   debug; unknown
rcvrdbg   debug; unknown
rcvrbuf   debug; RCVR Rx Buf status
rcvrid   debug; unknown
rcvrtest  debug; unknown
rcvrclear  debug; RCVR engine to be Set To Default (broken)
holdmode   debug; GPS Position Hold Mode - {EN or DI}
holdpos   debug; Position :  LAT(N 0:0:0.000) LON(E 0:0:0.000) H(0.00 m (0))
cabledelay  debug; get/set GPS Cable Delay in ns
timeraim  debug; timeraim {on/off}
posstatus  debug; returns pos, vel, geom, channel status
initpos   debug; RCVR GPS initial POSITION
avgpos   debug; RCVR GPS average POSITION
almanacin  debug; unknown
almanacout  debug; unknown
timemode  debug; set/get timemode {utc/gps}
gmtoffset  debug; set/get gmt offset
leapsec   debug; set/get leap second pending and accumulate status
pulsemode  debug; unknown
ppsoffset  debug; unknown
testdis   debug; unknown
gpgga   debug; unknown SYNTAX : COMMAND [00-60]
gpzda   debug; unknown SYNTAX : COMMAND [00-60]
gpgll   debug; unknown SYNTAX : COMMAND [00-60]
gpgsa   debug; unknown SYNTAX : COMMAND [00-60]
gpgsv   debug; unknown SYNTAX : COMMAND [00-60]
gpvtg   debug; unknown SYNTAX : COMMAND [00-60]
gprmc   debug; unknown SYNTAX : COMMAND [00-60]
gpalt   debug; unknown SYNTAX : COMMAND [00-60]
gpanc   debug; unknown SYNTAX : COMMAND [00-60]
gpacc   debug; unknown SYNTAX : COMMAND [00-60]
gpast   debug; unknown SYNTAX : COMMAND [00-60]
gptst   debug; unknown SYNTAX : COMMAND [00-60]
gpsrq   debug; unknown SYNTAX : COMMAND [00-60]
gpirq   debug; unknown SYNTAX : COMMAND [00-60]
gpdrq   debug; unknown SYNTAX : COMMAND [00-60]
gprrq   debug; unknown SYNTAX : COMMAND [00-60]
gpdie   debug; unknown SYNTAX : COMMAND [00-60]
gptlp   debug; unknown SYNTAX : COMMAND [00-60]
gptps   debug; unknown SYNTAX : COMMAND [00-60]
gpgpt   debug; unknown SYNTAX : COMMAND [00-60]
gprrm   debug; unknown SYNTAX : COMMAND [00-60]
gpclr   debug; unknown SYNTAX : COMMAND [00-60]
datum   debug; unknown

Cable Length RG 213 or Belden 8267 Delay Value
1m 5.0 nanoseconds
2 m 10.3 nanoseconds
5 m 25.2 nanoseconds
10 m 50.5 nanoseconds
15 m 75.7 nanoseconds
30 m 151.5 nanoseconds
50 m 252.5 nanoseconds

Cable Length LMR 400 Antenna Delay Value
1m 3.9 nanoseconds
2 m 8.0 nanoseconds
5 m 19.6 nanoseconds
10 m 39.3 nanoseconds
15 m 59.0 nanoseconds
30 m 118.0 nanoseconds
60 m 236.1 nanoseconds
110 m 432.9 nanoseconds

The delay factor is related to the specific velocity factor of your coax. If the cable you use has no additional signal delay time caused by the cable dielectric material (a velocity factor of 100%), the delay factor would be the time it takes light to travel the length of the coax. Light travels almost exactly one nanosecond per foot. RG/58 with a polyethylene dielectric (not foam) has a velocity factor of 66%. The specific calculations: 

Speed of Light = 186,284 miles per second.
5,280 (feet per mile) X 186,284 = 983,579,520 feet per second
983,579,520 X (10 -9 ) = .98357952 foot per nanosecond
.98357952 x 66% = .6491624832 (speed through RG/58)
1/.6491624832 (one over x function) = 1.5404463842 or 1.54 ns per foot delay 

So for your length of cable.....70 feet of RG/58 has a time delay of 107.8 nanoseconds. The HP manual gives some examples of other cables and various lengths. 

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