Meinberg GPS164xHS User Manual
Technical Information
Operating Instructions
GPS164xHS
GPS164/AQ/xHS
Contact Information
Meinberg Funkuhren GmbH & Co. KG
Lange Wand 9
D-31812 Bad Pyrmont
Telefon: ++49 (0) 52 81 / 9309-0
Telefax: ++49 (0) 52 81 / 9309-30
Internet: http://www.meinberg.de
Email: info@meinberg.de
December 16th, 2009
Table of contents
Contact Information............................................................................. 2
Content of the USB stick ..................................................................... 4
General information............................................................................. 5
Block diagram GPS164xHS................................................................. 6
GPS164xHS features............................................................................ 7
Time zone and daylight saving .................................................. 7
Pulse outputs .............................................................................. 8
Asynchronous serial ports .......................................................... 9
Time code outputs ...................................................................... 9
Introduction....................................................................... 9
Available time codes ...................................................... 10
Code generation .............................................................. 10
IRIG standard format ...................................................... 11
AFNOR time code format............................................... 12
Assignment of CF Segment in IEEE1344 mode ............ 13
DCF77 emulation ..................................................................... 14
Installation ......................................................................................... 15
Power supply ............................................................................ 15
Mounting the antenna ............................................................... 16
Powering up the system ........................................................... 16
The front panel layout........................................................................ 17
FAIL LED ................................................................................. 17
LOCK LED ............................................................................... 17
OCx LEDs ................................................................................. 17
BSL Key ................................................................................... 17
BNC connector DCF Out .......................................................... 18
Connectors TC_Out ( AM / DCLS ) ........................................ 18
BNC connector GPS Ant .......................................................... 18
Assignment of the terminal block ............................................ 18
Assignment of the DSUB connectors ...................................... 19
Replacing the lithium battery ............................................................ 19
CE label .............................................................................................. 19
Technical specifications GPS164xHS ............................................... 20
Front views ............................................................................... 23
Technical specifications of antenna ......................................... 24
Assembly with CN-UB/E (CN-UB-280DC) ............................ 25
Format of the Meinberg standard time string .......................... 26
Format of the SAT time string ................................................. 27
Format of the time string Uni Erlangen (NTP) ....................... 28
Format of the NMEA (RMC) string ........................................ 30
Format of the Computime Time String .......................... 31
The program GPSMON32 ................................................................. 32
Online Help .............................................................................. 33
Content of the USB stick
Besides this manual, the provided USB stick includes a setup program for the
monitor software GPSMON32. This utility can be used to configure Meinberg GPS
receivers via their serial ports and display status information of the module.
The software is executable under the following operating systems:
- Windows Server 2003
- Windows XP
- Windows 2000
- Windows NT
- Windows ME
- Windows 9x
If the USB stick is lost, the setup program can be downloaded for free at:
http://www.meinberg.de/english/sw/#gpsmon
4
General information
The Meinberg satellite receiver clocks of the GPS164xHS series are available with
several options. This manual describes the following models:
CDV27...91CAV042...001CDV042...001stuptuorelpuocotpostuptuoyalerSOMotohP
SHD461SPGX X
SHA461SPGXX
SHAD461SPGXXX
SHD/Q
A/461SPGX X
SHA/QA/461SPGX X
SHAD/QA/461SPGXX X
The vaiants differ in power supply and the type of DC-isolation of the programmable
pulse outputs. The differences are described in the relevant chapters, the name
GPS164xHS is used whenever common features of all types of clocks are specified.
The satellite receiver clock GPS164xHS has been designed to provide an extremly
precise time reference for the generation of programmable pulses. High precision
available 24 hours a day around the whole world is the main feature of the new
system which receives it's information from the satellites of the Global Positioning
System.
The Global Positioning System (GPS) is a satellite-based radio-positioning, navigation, and time-transfer system. It was installed by the United States Departement
of Defense and provides two levels of accuracy: The Standard Positioning Service
(SPS) and the Precise Positioning Service (PPS). While PPS is encrypted and only
available for authorized (military) users, SPS has been made available to the general
public.
GPS is based on accurately measuring the propagation time of signals transmitted
from satellites to the user´s receiver. A nominal constellation of 21 satellites together
with 3 active spares in six orbital planes 20000 km over ground provides a minimum
of four satellites to be in view 24 hours a day at every point of the globe. Four
satellites need to be received simultaneously if both receiver position (x, y, z) and
receiver clock offset from GPS system time must be computed. All the satellites are
monitored by control stations which determine the exact orbit parameters as well as
the clock offset of the satellites´ on-board atomic clocks. These parameters are
uploaded to the satellites and become part of a navigation message which is retransmitted by the satellites in order to pass that information to the user´s receiver.
The high precision orbit parameters of a satellite are called ephemeris parameters
whereas a reduced precision subset of the ephemeris parameters is called a satellite´s
almanac. While ephemeris parameters must be evaluated to compute the receiver´s
position and clock offset, almanac parameters are used to check which satellites are
in view from a given receiver position at a given time. Each satellite transmits its
own set of ephemeris parameters and almanac parameters of all existing satellites.
5
Block diagram GPS164xHS
66
GPS164xHS features
The GPS164xHS is designed for mounting on a DIN rail. The front panel integrates
five LED indicators, a hidden push button, an eight-pole terminal block, theree
DSUB- and three BNC-connectors. The receiver is connected to the antenna/converter unit by a 50 Ω-coaxial cable with length up to 300 m (when using RG58 cable). It
is possible to connect up to four receivers to one antenna by using an optional antenna
diplexer.
The navigation message coming from the satellites is decoded by GPS164xHS´s
microprocessor in order to track the GPS system time with an accuracy of better than
±250 nsec. Compensation of the RF signal´s propagation delay is done by automatical determination of the receiver´s position on the globe. A correction value computed from the satellites´ navigation messages increases the accuracy of the board´s
TCXO to ±5.10
-9
and automatically compensates the oscillators aging. The last recent
value is restored from the battery buffered memory at power-up.
Time zone and daylight saving
GPS system time differs from the universal time scale (UTC) by the number of leap
seconds which have been inserted into the UTC time scale after GPS has been
initiated in 1980. The current number of leap seconds is part of the navigation
message supplied by the satellites, so GPS164xHS´s internal real time is based on
UTC.
Conversion to local time including handling of daylight saving year by year can be
done by the receiver´s microprocessor if the corresponding parameters are set up
with the help of the software GPSMON32 (included Windows software).
7
Pulse outputs
The pulse generator of the satellite controlled clock GPS164xHS containes three
independant channels and is able to generate a multitude of different pulses, which
are configured with the software GPSMON32. The active state of each channel is
invertible, the pulse duration settable between 10 msec and 10 sec in steps of 10
msec. In the default mode of operation the pulse outputs are disabled until the
receiver has synchronized after power-up. However, the system can be configured to
enable those outputs immediately after power-up. The pulse outputs are electrically
insulated by optocouplers (GPS164xHS) or PhotoMOS relays (GPS164/AQ/xHS)
and are available at the terminal block.
The following modes can be configured for each channel independently:
Timer mode: Three on- and off-times per day per channel programmable
Cyclic mode: Generation of periodically repeated pulses.
A cycle time of two seconds would generate a pulse at
0:00:00, 0:00:02, 0:00:04 etc.
DCF77-Simulation
mode: The corresponding output simulates the DCF77 time telegram.
The time marks are representing the local time as configured by the user.
Single Shot Mode: A single pulse of programmable length is generated once a day at a
programmable point of time
Per Sec.
Per Min.
Per Hr. modes: Pulses each second, minute or hour
Status: One of three status messages can be emitted:
‘position OK’: The output is switched on if the receiver was able to
compute its position
‘time sync’: The output is switched on if the internal timing is
synchronous to the GPS-system
‘all sync’: Logical AND of the above status messages.
The output is active if position is calculated AND the
timing is synchronized
Time code: The un-modulated IRIG or AFNOR signal of the built in time code generator
is made available at the respective output.
Time string: The time string of the serial port COM1 is made available at the respective
output.
Idle-mode: The output is inactive
8
Asynchronous serial ports
Two asynchronous serial interfaces (RS-232) called COM0 and COM1 are available
to the user. In the default mode of operation, the serial outputs are disabled until the
receiver has synchronized after power-up. However, the system can be configured to
enable those outputs immediately after power-up. Transmission speeds, framings
and the kind of the time string can be configured separately. The serial ports are
sending a time string either once per second, once per minute or on request with
ASCII ´?´ only. The format of the output strings is ASCII, see the technical specifications for details. The corresponding parameters can be set up by GPSMON32 (included Windows software) using serial port COM0.
Optionally serial port COM1 can be delivered as an RS-485 interface.
Time code outputs
Introduction
The transmission of coded timing signals began to take on widespread importance
in the early 1950´s. Especially the US missile and space programs were the forces
behind the development of these time codes, which were used for the correlation of
data. The definition of time code formats was completely arbitrary and left to the
individual ideas of each design engineer. Hundreds of different time codes were
formed, some of them were standardized by the "Inter Range Instrumantation Group"
(IRIG) in the early 60´s. Detailed information about IRIG and other time codes can
be found on
http://www.meinberg.de/english/info/irig.htm
Except these time codes other formats, like NASA36, XR3 or 2137, are still in use.
The module GPS164TDHS however generates IRIG-B or AFNOR NFS-500 only.
Selection of the generated time code is done by using the monitor program
GPSMON32.
9
Available time codes
The time code generator of the module GPS164xHS is able to generate the timecodes shown below. The modulated codes (IRIG B122/B123, AFNOR, IEEE1344)
are available via the BNC-connector, the unmodulated codes (IRIG B002/B003 and
IEEE1344) via a DSUB connector in the front panel. The unmodulated codes are
available as a transistor output with internal pull up (470 Ω to +5V), with TTL-level
into 50 Ω and with RS422 level.
B002: 100pps, DC Level Shift pulse width coded, no carrier
BCD time of year
B122: 100pps, amplitude modulated sine wave signal, 1 kHz carrier frequency
BCD time of year
B003: 100pps,DC Level Shift pulse width coded, no carrier
BCD time of year, SBS time of day
B123: 100pps, amplitude modulated sine wave signal, 1 kHz carrier frequency
BCD time of year, SBS time of day
AFNOR: 100pps, amplitude modulated sine wave signal, 1 kHz carrier frequency
BCD time of year, complete date, SBS time of day
output level adapted
IEEE1344: Code according to IEEE1344-1995
100pps, AM-Sine wave signal, 1kHz carrier frequency,
BCD-time of year, SBS time of day
IEEE1344 extensions for:
date, timezone, daylight-saving and leap second
in control functions ( CF ) segment.
also see table ‘Assignment of CF segment in IEEE1344 mode’
Code generation
In the default mode of operation the IRIG/AFNOR ti mecode outputs are disabled
until the GPS-receiver has been synchronized after power-up. The generation of the
IRIG-code only starts after synchronization therefore.
If the code must be available immediately after power-up, the software GPSMON32 can be used to enable the time code output without synchronization of the
GPS-receiver by setting the enable flag 'pulses' to 'always'. In this mode of operation
the IRIG-code is not locked to UTC-second until synchronization.
10
IRIG standard format
11
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