Gems OS Series User manual

Shenzhen GEMS Navigation Electronics Co., Ltd. 2/F, Building 6, Rundongsheng Industrial Zone, Longzhu
Community, Xixiang Street, Bao'an District, Shenzhen City, China
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GPS over Fiber Timing Distribution System
OS Series
Remote unit(OS208R)
Local unit(OS208L)

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Product Introduction
This system consists of Remote unitand near-end host. The Remote unitreceives input through
two ends and possesses 1 to 8 optional optical fiber interfaces through which signals are transmitted
to near-end hosts. The Local unitoutputs signals to GPS device through 1-8/16 ports. The satellite
signals received by Local unitfrom the Remote unitthrough optical fiber are amplified and distributed
to the output ports, which, at the same time, offer GPS signals to 8/16 ports. After entering GNSS
signal system management terminal and setting IP, this system can display the connection status of
each port, number of visible GPS satellites and C/No value, number of visible Beidou satellites and
C/No value, position, etc.
The system averagely distributes the signals received by active GPS receiving antennas to 8-way
output ports and supplies them to GPS receiving equipment. With gain of 30dB and dual antennas
for the far-end host, the system integrity is guaranteed. In this application solution, the system can
configure its output port as DC output port for supplying power to active GPS antennas that are
connected to the input port. Other output ports will have a 200 Ohm DC load for simulating the DC
loss of any receiver antenna connected to those ports.
Optical fiber interface is used as an independent interface for signals transmission between
Remote unitand Local unitvia optical fibers.

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System connection
GPS antenna 1 GPS antenna 2
Remote unit
Local unit
Fiber

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Basic Features:
Dual antennas, auto and manual switching function (far-end host);
Gain: 30dB fixed gain;
Status monitoring and alarm of antennas and output ports;
Standard configuration of far-end host: 1 optical transmitting port (maximum optional 8);
Standard configuration of near-end host: 1 optical receiving port;
（(Near-end host) 2-way dry contact alarm function (RJ45 interface);
(Far-end host) 4-way dry contact alarm function (RJ45 interface);
Buzzer alarm function;
Standard configuration of output port: 8 ports (12/16 ports optional);
Real-time display of information of GPS/Beidou2 B1
Dual 48V DC power supply support;
Software management, network management and monitoring;
Support LNA backup and testing;
Long-distance optical fiber transmission of signals;
Electrical parameters Working temperature: -20 to 65℃; storage temperature: -30 to 80℃
Parameter
Specification
Min.
Nomin
al
Max.
Unit
Frequency range
Antenna - Any port (far-end port)
1557.5
1587.5
MHz
I/O impedance
Input, all output ports
50
Ω
Gain
30dB
Input -output, unused port - 50Ω load
30
dB
Input voltage standing wave
ratio (far-end host)
All ports - 50Ω load
1.5:1
-
Output voltage standing wave
ratio
All ports - 50Ω load
1.5:1
-
Noise factor
4
dB
Pass band ripple
Antenna - any port, unused port - 50Ω load
3
dB
Maximum output power
Antenna - any port, unused port - 50Ω load
-30
dBm
Frequency error
5
×10⁻⁸
Out-of-band spurious
9KHz - 150KHz
-36
dBm
/100KHz
150KHz - 30MHz
-36
30MHz - 1GHz
-36
1GHz - 12.75GHz
-30
DC input
DC blocking, output port has a 200Ω
load
5
VDC
Dual DC 48V
39
48
57
Opt
Current
Remote unit
150
200
mA
Current
Local unit
80
100
mA

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Optical wavelength
Sending
1310
nm
Receiving
1100~1620
nm
Optical fiber transmission
distance
60
Km
Optical Power
Sending
8
dBm
Optical Power
Receiving
-30
dBm
Performance Index
No.
Function
Description
Remarks
1
Compatibility of
timing system
Support two timing systems: Beidou/GPS and able to
automatically switch to another timing system in case of
fault of any system, and manual intervention is not
required.
2
Load capacity
Can connect up to 8/12/16 BBUs normally
3
Expandability
With full configuration (one 16-port host +16 slaves), the
equipment supports maximum 256 synchronous signal
ports of BBU.
4
Antenna fault testing
function of far-end
host
Step 1: Plug in the antenna of channel 1 and then the device
indicator on the antenna 1 will be normally on; step 2: pull
out the antenna on channel 1 and then the indicator on
antenna 1 will be off. When the above operation
requirements are satisfied, the antenna runs normally;
otherwise, antenna fault is judged; the operation method of
channel 2 is same to that of channel 1.
5
Working status
indicator
The equipment can indicate the onsite working status via
the indicator, reflect whether the main circuit and the
standby circuit run normally and send alarm for fault.
6
Dry contact alarm
function of Remote
unit
Provide 4-way dry contact alarm signals and support power
failure alarm. Prompt alarm information to the network
management center, covering: Antenna 1, antenna 2, power
supply, host output.
Dry contact alarm
function of Local unit
Provide 2-way dry contact alarm signals and support power
failure alarm. Prompt alarm information to the network
management center, including: Power supply, host output.
7
Buzzer alarm function
Prompt fault of this machine by sound and the fault alarm
sound can be turned off manually.
8
Network management
and monitoring
function
Mainly used to monitor the working status of this machine
on the network management server.
9
Positioning
information indication
The equipment can indicate the positioning information of
main circuit, e.g. the longitude and latitude, by LCD.
10
BBU connection
indication function
After BBU device is connected to the system interface, the
system can automatically indicate that the device is
connected and runs normally.

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11
Output port
connection indication
function
With host output port connection indication function, this
equipment can respectively reflect the connection status of
host output port to BBU and slaves and the suspension
status through indicators.
12
LNA testing
Two independent low noise amplifiers (LNA) are available
inside the host. In case of fault of any LNA, the equipment
runs normally. The indicator is normally on when LNA
runs normally or off in case of LNA fault.
13
Time source
self-timing
With internal self-timing function, the equipment can
implement self-timing of time source when external GPS
satellite time source is disabled.
15
Sending and receiving
remote optical signals
Realize remote transmission of signals in km and lower
down the level of difficulty in cabling.

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Dual input antenna
interfaces
Earthing
Optical fiber
interface
LCD screen
Remote unit
8-16-port output
Power
switch
+48V dual input
interfaces
Net access and client
network interface
Status
indicator
Antenna switch key and status
memory
Local unit
Earthing
+48V dual input
interfaces
Power
switch
LCD
screen
8-16-port output
Status indicator
Net access and client
network interface
Antenna switch key and status
memory
Optical fiber
interface

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Operating Instructions
This system supports dual+48V power supply. After power on, the indicators of power supply A
and power supply B light on. Two input ports of Remote unitare connected to GPS antennas. Upon
successful connection, antenna 1 and antenna 2 indicators are on. The optical fiber interface is round
FC-APC interface. When the optical fiber module runs normally, the optical transmitting indicator
light is on and the 8/12/16 output ports can be connected to BBU or GPS device. When the output
port is connected to each BBU device, corresponding output indicator is on. When the satellite signal
is locked, the lock indicator lights up. RJ45 network interface can be connected to client and client’s
PC so that operator can view the equipment connection state and change the equipment state in real
time via the client. Equipment alarm is realized through the alarm interface. After the equipment is
connected, either antenna 1 indicator or antenna 2 indicator will flash, indicating the antenna is in
service. The key “Switch" can be used to switch between two antennas and it has automatic and
manual mode. Under automatic mode, the system automatically selects the antenna with stronger
signals. In manual mode, press down the key to select the antenna for running manually. Operator
can view the basic parameters of running antenna and equipment on the LCD screen.
①Power supply: Support dual 48V power supply and adopt dual power supply modules design.
In the event of fault of any power supply module, standby module can be used to guarantee the
normal running of equipment; the equipment provides burn-proof function so that the equipment
parts won’t be burned out if the positive pole and negative pole of power supply are reversely
connected.
②
Antenna switch: Remote unitsupports antenna switching by the antenna switch button, alarm
reset and memory function. By long-pressing the key, the connection status of existing device ports
are recorded. In case of device alarm, long-press the key to reset the device manually. Local unitonly
supports memory and alarm function.
③
Alarm: Red alarm light will flash all the time unless two power supply units and two antennas
are connected properly. Only after power supply and antennas are connected properly, the alarm light
can be disabled by pressing down the antenna switch button for 5s.
④
Satellite lock indicator: When a satellite is locked, the satellite lock indicator is normally on.
⑤Optical fiber indicator: The indicator is on, indicating the optical fibers are in normal use;
the indicator is off in case of optical fiber fault.
⑥Antenna indicator: When two-way antennas are connected normally, corresponding
indicator will be normally on.
⑦
LNA indicator: When it is on, it indicates that LNA functions normally; when it is off, it
means fault of LNA function and it’s required to check if device output is short circuited.

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⑧Network management alarm interface: Connect network management through RJ45 network
interface to monitor the device; RJ45 interface is dry contact interface through which the device
sends alarm for fault.
Antenna selection and status display:
Select antenna mode actively: Select “Auto” or other antenna mode. The indicators on the panel
will indicate the operation mode. If “Auto” mode is selected, the “Antenna 1” flashes green while the
Antenna 2 is normally on; it’s same when “Antenna 1” mode is selected, the “Antenna 1” flashes
green and the Antenna 2 is normally on; when “Antenna 2” mode is selected, “Antenna 2” green
light flashes and “Antenna 1” is normally on; antenna mode can be selected by pressing keys on the
device front panel. Press down the key “Antenna Switch” to switch between three antenna modes
alternately. The LCD will display the antenna mode in use. When the optical module runs normally,
you can check whether the optical module runs normally via the LCD screen or corresponding
indicator. If the indicator is on, it means the module runs normally.
If antenna encounters open circuit or short circuit, the green light of “Satellite lock” on the front
panel will be off and the red “Alarm” light flashes, giving warning. If the memory output port (BBU
or slave) is disconnected, the red light on the front panel flashes and buzzer sends alarm sound.
Alarm: The red alarm light device will flash all the time unless two power supply units and two
antennas are connected properly. Only after power supply and antennas are connected properly, the
alarm light can be disabled by pressing down the antenna switch button for 5s.
Antenna indicator: When the lock indicator lights on, it means the satellite has been locked; when
the antenna 1 indicator flashes, it reflects that antenna 1 is in use; it’s also same to antenna 2.
The device LNA functions normally when the LNA indicator is on; when the indicator is off, it
indicates LNA fault.
Alarm light is on when no
device is connected to the
antenna output port

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4-way Dry Contact Alarm Function (Far-end Host)
Definition of dry contact alarm function
Power supply alarm: When the power supply is connected normally,
pin 1 and pin 2 are closed. In case of open circuit or short circuit of
any power supply, pin 1 and pin 2 are disconnected.
Output port alarm: The alarm of output port takes effects only
with memory. After output port is connected normally, pin 1 and pin
3 are disconnected. If any port is disconnected or short circuited, pin 1
and pin 3 are closed.
Antenna port alarm: When antenna 1 is connected normally, pin
1 and 4 are disconnected; if the antenna 1 is disconnected or short
circuited, pin 1 and pin 4 are closed; when antenna 2 is connected
normally, pin 1 and pin 5 are disconnected; in the event of
disconnection or short circuit of antenna 2, pin 1 and pin 2 are closed.
2-way dry contact alarm function (Near-end host)
Definition of dry contact alarm function
Power supply alarm: When the power supply is connected normally,
pin 1 and pin 2 are closed. In case of open circuit or short circuit of
any power supply, pin 1 and pin 2 are disconnected.
Output port alarm: The alarm of output port takes effects only with
memory. After output port is connected normally, pin 1 and pin 3 are
disconnected. If any port is disconnected or short circuited, pin 1 and
pin 3 are closed.
Common Faults Troubleshooting
Fault
Cause
Handling Method
Alarm light flashes
Device interface is
disconnected and
fault is not reset
Check if antenna power interface is
connected successfully, if the output is
normal. Long press the key to reset the fault.
Antenna indicator is off
Poor connection of
antennas
Check if antennas are connected properly
and if the interface is in good contact.
LNA light is off
Short circuit of
input port
Check the antenna input port and antennas
for short circuit
Buzzer alarm
No reset after
eliminating fault
Long press the Reset key.
Pin
Definition
1、8
1, 8
COM
(common
terminal)
2
Power alarm
3
Output port
alarm
4
Antenna 1
alarm
5
Antenna 2
alarm
Pin
Definition
1、8
1,8
COM
(common
terminal)
2
Power alarm
3
Output port
alarm