Meinberg GPS170SV User manual

MANUAL
GPS170SV
GPS Receiver Eurocard
4th November 2013
Meinberg Radio Clocks GmbH & Co. KG

Table of Contents
1 Impressum 1
2 General Information GPS 2
3 GPS170SV Features 3
3.1 Time Zone and Daylight Saving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2 PulseandFrequencyOutputs..................................... 3
3.3 TimeCaptureInputs ......................................... 4
3.4 Asynchronous Serial Ports (optional 4x COM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.5 DCF77Emulation........................................... 4
3.6 Programmable pulse (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.7 TimeCode(optional)......................................... 6
3.7.1 AbstractofTimeCode .................................... 6
3.7.2 BlockDiagramTimeCode .................................. 7
3.7.3 IRIGStandardFormat..................................... 8
3.7.4 AFNORStandardFormat................................... 9
3.7.5 Assignment of CF Segment in IEEE1344 Code . . . . . . . . . . . . . . . . . . . . . . . . 10
3.7.6 GeneratedTimeCodes .................................... 11
3.7.7 Selection of Generated Time Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.7.8 Outputs ............................................ 12
3.7.9 TechnicalData ........................................ 12
4 Installation 13
4.1 TheFrontPanelLayout........................................ 13
4.2 RS232COM0 ............................................. 13
4.3 PowerSupply ............................................. 14
4.4 MountingtheGPSAntenna...................................... 14
4.4.1 Example:............................................ 14
4.4.2 Antenna Short-Circuit Assembly with surge voltage protection . . . . . . . . . . . . . . . 15
4.5 PoweringUptheSystem ....................................... 16
5 Safety Instructions 17
5.1 Skilled/Service-Personnel only: Replacing the Lithium Battery . . . . . . . . . . . . . . . . . . . 17
5.2 CE-Label................................................ 17
6 Technical Specifications GPS170 18
6.1 Oscillatorspecications ........................................ 20
6.2 Technical Specications GPS Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.3 TimeStrings.............................................. 22
6.3.1 Format of the Meinberg Standard Time String . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3.2 Format of the Meinberg GPS Time String . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.3.3 Format of the Meinberg Capture String . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.3.4 Format of the SAT Time String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.3.5 Format of the Uni Erlangen String (NTP) . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.3.6 Format of the NMEA 0183 String (RMC) . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.3.7 Format of the NMEA 0183 String (GGA) . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.3.8 Format of the NMEA 0183 String (ZDA) . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.3.9 Format of the ABB SPA Time String . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.3.10 Format of the Computime Time String . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.3.11 Format of the RACAL standard Time String . . . . . . . . . . . . . . . . . . . . . . . . . 33
6.3.12 Format of the SYSPLEX-1 Time String . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.3.13 Format of the ION Time String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.4 SignalDescriptionGPS170 ...................................... 36
0

Page 0
7 The program GPSMON32 37
7.1 SerialConnection ........................................... 37
7.2 NetworkConnection.......................................... 37
7.3 OnlineHelp .............................................. 37
0 Date: 4th November 2013 GPS170SV

Page 1
1 Impressum
Meinberg Radio Clocks GmbH & Co. KG
Lange Wand 9, 31812 Bad Pyrmont - Germany
Phone: + 49 (0) 52 81 / 93 09 - 0
Fax: + 49 (0) 52 81 / 93 09 - 30
Internet: http://www.meinberg.de
Mail: [e-mail]
Date: 2010-05-20
GPS170SV Date: 4th November 2013 1

Page 2 2 General Information GPS
2 General Information GPS
The satellite receiver clock GPS170 has been designed to provide extremly precise time to its user. The clock has
been developed for applications where conventional radio controlled clocks cant meet the growing requirements
in precision. High precision available 24 hours a day around the whole world is the main feature of this system
which receives its information from the satellites of the Global Positioning System.
The Global Positioning System (GPS) is a satellite-based radio-positioning, navigation, and time-transfer sys-
tem. 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 24 satellites together with several 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 oset 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 oset 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 oset, 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.
2 Date: 4th November 2013 GPS170SV

Page 3
3 GPS170SV Features
The GPS170SV hardware is a 100mm x 160mm microprocessor board. The 40.6mm wide front panel integrates
two LED indicators and one covered push button. The receiver is connected to the antenna/converter unit by a
50 ohm coaxial cable (refer to "Mounting the Antenna"). Feeding the antenna/converter occurs DC insulated
via the antenna cable. Optional an antenna diplexer for up to four receivers connected to one antenna is available.
The GPS170SV is using the "Standard Positioning Service" SPS. Navigation messages coming in from the satel-
lites are decoded by the GPS170SV microprocessor in order to track the GPS system time. Compensation of
the RF signals propagation delay is done by automatic determination of the receivers geographical position. A
correction value computed from the satellites navigation messages increases the accuracy of the boards oven
controlled master oscillator (OCXO) and automatically compensates the OCXOs aging. The last state of this
value is restored from the battery buered memory at power-up.
The GPS170SV has several dierent optional outputs, including three progammable pulses, modulated / un-
modulated timecode and max. four RS232 COM ports, depending on the hardware conguation. Additionally,
you can get the GPS170SVwith dierent OCXOs (e.g. OCXO- LQ / MQ / HQ / DHQ or Rubidium) to cover
all levels of accuracy requirements.
You can review and change the hard- and software conguration options of the clock with the GPSMON32
application(see corresponding section in this manual).
3.1 Time Zone and Daylight Saving
GPS system time diers from the universal time scale (UTC) by the number of leap seconds which have been
inserted into the UTC time scale since GPS was initiated in 1980. The current number of leap seconds is part of
the navigation message supplied by the satellites, so the internal real time of the GPS170 is based on UTC time
scale. Conversion to local time and annual daylight saving time can be done by the receiver's microprocessor if
the corresponding parameters are set up by the user.
3.2 Pulse and Frequency Outputs
The pulse generator of GPS170 generates pulses once per second (P_SEC) and once per minute (P_MIN).
Additionally, master frequencies of 10 MHz, 1 MHz and 100 kHz are derived from the OCXO. All the pulses are
available with TTL level at the rear connector.
Frequency Outputs (optional)
The included synthesizer generates a frequency from 1/8 Hz up to 10 MHz synchronous to the internal timing
frame. The phase of this output can be shifted from -360
◦
to +360
◦
for frequencies less than 10 kHz. Both
frequency and phase can be setup from the front panel or using the serial port COM0. Synthesizer output is
available at the rear connector as sine-wave output (F_SYNTH_SIN), with TTL level (F_SYNTH) and via an
open drain output (F_SYNTH_OD). The open drain output can be used to drive an optocoupler when a low
frequency is generated.
In the default mode of operation, pulse outputs and the synthesizer output are disabled until the receiver has
synchronized after power-up. However, the system can be congured to enable those outputs immediately after
power-up. An additional TTL output (TIME_SYN) reects the state of synchronization. This output switches
to TTL HIGH level when synchronization has been achieved and returns to TTL LOW level if not a single satellite
can be received or the receiver is forced to another mode of operation by the user.
GPS170SV Date: 4th November 2013 3

Page 4 3 GPS170SV Features
3.3 Time Capture Inputs
Two time capture inputs called User Capture 0 and 1 are provided at the rear connector (CAP0 and CAP1) to
measure asynchronous time events. A falling TTL slope at one of these inputs lets the microprocessor save the
current real time in its capture buer. From the buer, capture events are transmitted via COM0 or COM1 and
displayed on LCD. The capture buer can hold more than 500 events, so either a burst of events with intervals
down to less than 1.5 msec can be recorded or a continuous stream of events at a lower rate depending on the
transmission speed of COM0 or COM1 can be measured.
The format of the output string is ASCII, see the technical specications at the end of this document for details.
If the capture buer is full a message "** capture buer full" is transmitted, if the interval between two captures
is too short the warning "** capture overrun" is being sent.
3.4 Asynchronous Serial Ports (optional 4x COM)
Four asynchronous serial RS232 interfaces (COM0 ... COM3) 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 congured to enable those outputs immediately after power-up. Transmission speeds, framings
and mode of operation can be congured separately using the setup menu. COM0 is compatible with other radio
remote clocks made by Meinberg. It sends the time string either once per second, once per minute or on request
with ASCII ? only. Also the interfaces can be congured to transmit capture data either automatically when
available or on request. The format of the output strings is ASCII, see the technical specications at the end
of this document for details. A separate document with programming instructions can be requested dening a
binary data format which can be used to exchange parameters with GPS170 via COM0.
3.5 DCF77 Emulation
The satellite controlled clock generates TTL level time marks (active HIGH) which are compatible with the time
marks spread by the German long wave transmitter DCF77. This long wave transmitter installed in Mainingen
near Frankfurt/Germany transmits the reference time of the Federal Republic of Germany: time of day, date
of month and day of week in BCD coded second pulses. Once every minute the complete time information is
transmitted. However, the generates time marks representing its local time as congured by the user, including
announcement of changes in daylight saving and announcement of leap seconds. The coding sheme is given
below:
M Start of Minute (0.1 s)
R RF Transmission via secondary antenna
A1 Announcement of a change in daylight saving
Z1, Z2 Time zone identification
Z1, Z2 = 0, 1: Daylight saving disabled
Z1, Z2 = 1, 0: Daylight saving enabled
A2 Announcement of a leap second
S Start of time code information
P1, P2, P3 Even parity bits
0
10
20
30
40
50
R
M
1
4
2
1
20
10
8
4
2
1
P2
02
01
8
4
2
1
2
4
8
10
1
2
4
8
10
20
40
80
3
P
A1
Z1
Z2
A2
S
1
2
4
8
10
20
40
1P
Minute
(reserved)
Hour
Day of Month
Day of Week
Year of the Century
Month of Year
Time marks start at the beginning of new second. If a binary "0" is to be transmitted, the length of the
corresponding time mark is 100 msec, if a binary "1" is transmitted, the time mark has a length of 200 msec.
The information on the current date and time as well as some parity and status bits can be decoded from the
time marks of the 15th up to the 58th second every minute. The absence of any time mark at the 59th second
of a minute signals that a new minute will begin with the next time mark. The DCF emulation output is enabled
immediately after power-up.
4 Date: 4th November 2013 GPS170SV

3.6 Programmable pulse (optional) Page 5
3.6 Programmable pulse (optional)
At the male connector Typ VG64 there are three programmable TTL outputs (Prog Pulse 0-2), which are arbi-
trarily programmable.
Other technical details are described at the end of this manual.
GPS170SV Date: 4th November 2013 5

Page 6 3 GPS170SV Features
3.7 Time Code (optional)
3.7.1 Abstract of Time Code
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 denition of time code formats was completely arbitrary and left to the individual
ideas of each design engineer. Hundreds of dierent time codes were formed, some of which were standardized
by the "Inter Range Instrumentation Group" (IRIG) in the early 60s.
Except these "IRIG Time Codes", other formats like NASA36, XR3 or 2137 are still in use. The board GPS170
however generates the IRIG-B, AFNOR NFS 87-500 code as well as IEEE1344 code which is an IRIG-B123 coded
extended by information for time zone, leap second and date. Other formats may be available on request.
A modulated IRIG-B (3Vpp into 50W) and an unmodulated DC level shift IRIG-B (TTL) signal are available
at the VG64 male connector of the module.
6 Date: 4th November 2013 GPS170SV