No. 377, Nehru Nagar, Chennai, Tamil Nadu

600096 Ph: 044-23454060,61

www.serteltelser.com,www.sertelelectronics.com

Sertel NTP Server(T-GPS-300-NTPS)

A Sertel Electronics Manual

Contents

About 2

Problem Statement 2

Details 2

Abstract 2

Test/Inspection Report 2

Introduction 3

Active GPS Receiver (T-GPS-300) 4

GPS ANTENNA 6

GPS RECIVER 9

SERTEL NTP Configuration

Procedure 10

WARRANTY 22

About

This document is the Operation &

Maintenance, Installation manual for Sertel

GPS Clock.

Problem Statement

O & M Manual

Details

1) Installation Details

2) Settings details

Benefit 1

Sertel T-GPS-300 is a highly user-friendly

device. The operations are easy-to-

understand and completely simple for the

operator to handle. The system requires

absolutely less maintenance and has very

high MTBFs.

Abstract

Characteristics and technical details of

system & each output is Explained below.

Test/Inspection Report

Test Report

Introduction

The salient features of Sertel’s Synchronization system are as follows:

Master Clock and Slave Clock

• Synchronized to GPS receiver (through satellite)

• The slave clock can be connected to entire plant at various locations displaying the

same

Various Time Synchronization equipments to which our outputs are compatible for time

synchronization

a) Electrical equipments Synchronization:

Event recorders, disturbance recorder, fault recorder and sequential event recorder.

PLC’s, data acquisition system and other intelligence or RTU (remote terminal unit).

b) Instrumentation Synchronization:

Intelligence instrumentation PLC’S, DCS, DAS, SCADA and other intelligence RTU’S.

c) Networking of Computers

d) Frequency Monitoring

e) Power Monitoring

f) Calibration for frequency

Active GPS Receiver (T-GPS-300)

A fundamental deficiency of any ephemeris extension system is unknown future events.

This is typically the issues faced by all GPS receivers. The receiver will not be able to

know about satellites that will have become unhealthy, have undergone a clock swap, or

have had a maneuver (change in position). This means that the GPS Receiver engine

might rarely mistake a wrong satellite position as the true satellite position. However,

provided that there are enough other good satellites, the Receiver algorithms will

eventually eliminate a defective orbit from the solution. Effectively two satellites are

enough for making this decision by the receiver.

Any GPS receiver locking up on a GPS satellite has to do a two-dimensional search for

the signal.

The first dimension is time

-- the GPS signal structure for each satellite consists of a 1023 bit long

pseudo-random number (PRN) sequence sent at a rate of 1.023 megabits/sec,

i.e. the sequence repeats every millisecond.

For this data acquisition, the receiver needs to set an internal clock to the correct one of

the 1023 possible time slots by trying all possible values. Sertel’s GPS has NPL certified

internal clock OCXOs which maintain its timing accuracy of ns level. Most receivers stop

and dwell at each of the possible steps for a couple of milliseconds, i.e. the receiver take

1-2 seconds to try all the possibilities.

The second dimension is frequency.

-- The receiver must correct for inaccuracies in the apparent Doppler frequency of the

satellite and "zero-beat" the signal. Usually a receiver's crystal oscillator may be off by

up to +/- 10 kHz or so, so there are 20ish frequency cells that have to be tested. And

this process must happen for all N satellites that are in use. So, the

acquisition process can be quite laborious depending on the sky view of the antenna

position.

The longer a receiver observes the sky the more satellites it will have seen. At the

equator, and with full sky view, approximately ten satellites will show up in a one hour

window. After four hours of observation approx.16 satellites (i.e. half the constellation),

after 10 hours approx. 24 satellites (2/3rd of the constellation), and after approx. 16

hours the full constellation will have been observed. Lower sky visibility reduces these

figures. This means any obstruction in line of sight of Antenna to the Receiver & the

satellites. Further away from the equator the numbers improve because the satellites

can be seen twice a day. E.g. at 47 degrees north the full constellation can be observed

in approx. 12 hours with full sky view.

The usual search strategy our receivers adopt to start at an oscillator frequency

predicted on the basis of

(a) What is current Receivers approximate position? (Based on either the last known

position or last sync position),

(b) Where are the satellites now and what is their apparent velocity (based on the

almanac data down linked from the satellite and stored in the receiver's

memory), and

(c) What is the best guess for the receiver's crystal oscillator error (based on the last

known error and the current temperature in case of OCXO). This is the reason Sertel has

its own OCXO which maintains a constant temperature through its oven & helps

reducing the error of crystal used substantially.

After the receiver "smells" a signal, it establishes two tracking loops -- one is a phase-

locked loop in the frequency domain and the other is a time-locked loop in 1023 bit

code space domain with the goal of tracking both the code and carrier phases for that

signal.

Once it acquires lock on the first satellite it can start extracting data from the GPS

signals. From there on, after synchronization, timing accuracy is maintained at 1PPS

level exactly matching the GPS epoch.

Sertel’s GPS reception strategy is to start with the highest satellites in the sky and try to

get 2 satellites in lock. After the first 2 are found, the receiver has a fairly complete story

on the time/frequency characteristics and it immediately opens up and looks for more

satellites, and it uses them after another 30-60 seconds (average 45 sec). This creates a

completely healthy environment to maintain a timing accuracy of the order of ‘ns’ level

(certified by NPL(India)). Sertel’s receivers have more physical channels, so they can do

more parallel searches requiring less overhead in terms of time.

Getting a lock on by the GPS receivers on the ground usually takes some time especially

where the receiver is in a moving vehicle or in dense urban areas. The initial time

needed for a GPS lock is usually dependent on how the GPS receiver starts. There are

three types of start - hot, warm and cold.

Summarizing

GPS ANTENNA

MODEL NO: T-GPA-014

TYPE: HELICAL

MOUNT: FIXED(NECESSARY MOUNTING BRACKETS WILL BE PROVIDED)

AXIAL RATIO: 5db

CO-AXIAL CABLE: LOW LOSS CO-AXIAL CABLE(0.33db/meter), 100 METER ALONG WITH MATCHING CONNECTORS.

CONNECTOR: TNC CONNECTOR

TOTAL GAIN: OVER 30 db

NOISE FIGURE: LESS THAN 2.6db

SUPPLY VOLTAGE: 5V DC INTERNAL SUPPLY OPERATING TEMPERATURE: -30 TO + 80°C

STORAGE TEMPERATURE: - 40 TO + 85°C

MOUNTING: WALL MOUNTING

Sertel’s GPS receiver Configuration is as follows

Numbers of channel 16 channels

Position-Fixing System All-In-View SPS (DGPS RTCM-SC104)

Frequency 1575.42 MHz

Tracking Capability 12 Satellites simultaneously including 1 WAAS supporting

channel

Protocol NMEA Type

WAAS Support 1 Channel

Uses DGPS and the function to deselect unhealthy satellites

GPS-Fix data Renewal Rate 1 Second

1PPS Output UTC-Synchronized (1 pulse/second)

Acquisition/Tracking Specifications

Initial Acquisition Time 8.4 Seconds Hot Start (Open Sky)

36 seconds Warm Start (Open Sky)

44.9 Seconds Cold Start (Open Sky)

Re-acquisition Time 2 Seconds

(-127dBm or stronger signal interrupted for 10 seconds or

less)

Horizontal Accuracy (2drms) 5.6m

Vertical Accuracy (2drms) 7.3m

Power Supply

Supply Voltage / Current Voltage: 3.0 to 3.6 Vdc

Current: Max 72 mA at 3.6 Vdc

External Back-up power Voltage: 2.1 to 3.6 Vdc

Current: 200 uA when Vcc = 3.6 Vdc

10uA when Vcc = 0.0 Vdc

Ambient Conditions Operating temperature: -30°C - +80°C

Storage temperature: -40°C - +85°C

Dimensions 20.8 mm (w) x 33.8 (l) x 6.3 mm (h)

Mass 8g (0.2 oz)

GPS RECIVER

MODEL T-GPS-300

TYPE MICRO CONTROLLER TYPE DISPLAY BACKLIT LCD DISPLAY 24 HOURS FORMAT

TIME ACCURACY BETTER THAN 1 PPM INPUT 1575.14 MHZ FROM ANTENNA

INPUT CONNECTOR BNC

OUTPUT NTP OUTPUT,RS232,SLAVE OUTPUT

O/P CONNECTORS RJ 45 CONNECTOR FOR NTP OUTPUT,9 PIN D CONNECTOR FOR RS232,BARRIER CONNECTOR FOR SLAVE OUTPUT

FRONT PANEL LCD DISPLAY TO SHOW REQUIRED DATA AND STATUS AND NUMBER OF

SATELLITES), VALID DATA LED

BACK PANEL

90 TO 260 V AC/DC INPUT CONNECTOR, FUSE, ON/OFF SWITCH, RS 232 , 1 PPS OUTPUT CONNECT THROUGH 9 PIN D CONNECTOR NTP OUTPUT RJ 45 CONNECTOR ALARAM CONTACT TERMINAL.

SUPPLY VOLTAGE 90 TO 260V AC/DC SUPPLY FROM MAIN SUPPLY

ENVIRONMENTS TEMP. : 0-50 °C RH UP TO 95% NON CONDENSING

MOUNTING TO SUIT STANDARD 19” RACK SYSTEM

DIMENSION : 2U (H) X 484 (W) X 325 (D)

SERTEL NTP Configuration Procedure

STEPS TO CHANGING IP ADDRESS: (Windows Platform)

NOTE1:”SWITCH ON THE UNIT AND CONNECT THE ETHERNET CABLE WITH THE NTP

UNIT”.

NOTE2:”CONNECT TO SERTEL SYSTEM USING FACTORY SET IP ADDRESS :

192.168.1.254”.

ON Windows,

Click START at the bottom left corner of the desktop.

Click Run.

Please "telnet 192.168.1.254" and click ok.

Prompt should show

ts7200 login: Please type "admin" & Enter.

Password: Please type "ntp" & Enter.

Now you can see '$' symbol.

Please type the command "cd /etc/sysconfig" then press enter button.

Please type the command "vi ifcfg-eth0"then press enter button.

It will show IP address and subnet mask details.

Here you can see IPADDR=192.168.1.254 at the second line. Please ask any VI Editor

professional to do the following steps.

Press down key to second line then press right (->) key to move cursor right side up to

end (IPADDR=192.168.1.254_).

Press x button to erase (IPADDR=_).

Now Sertel's default IP address is deleted.

Enter "i"(Insert Mode) button once, then you press right (->) key once (this is for give 1

space between numbers and letters).

Please type your required network IP address (Note: Please do not use any existing IP

address in your network).

After type your new IP address press Esc button two times.

Please SAVE by typing ":wq"(colon wq) press Enter.

Please type, "reboot". This reboots the system and changes the IPAddress.

Now your ntp server IP addresses have been changed.

STEPS TO SYNCHRONISE WITH (windows XP and windows 2003) SYSTEM:

Click "START" at the bottom left corner of the desktop then go to Run.

Type "regedit" then enter.

Click HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32time\Time-

Providers\Ntpclient. (root key for the time service).

Right click specialpollinterval and click modify and delete the value 604800 and type 3C.

Click KEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32time\config (root

key for the time service).

Right click MaxNegPhaseCorrection and click modify and delete the value 54000 and

type ffffffff.

Right click MaxPosPhaseCorrection and click modify and delete the value 54000 and

type ffffffff.

Right click Update Interval and delete the value 00057e40 and type 3C.

Right click the time at the right bottom corner.

Select Adjust date/time.

It will show date and time properties.

Now you have to select Internet Time. And you have to tick the option that

Automatically synchronize with Internet Time Server.

Then you have to enter your new NTP server IP address inside the server box.

Now you click Apply, then click Update Now option, then click ok.

Now your system gets synchronized.

Close the date and time window.

This Synchronizes your Windows time with SERTEL’s Time Sync Server.

STEPS TO SYNCHRONISE WITH (Linux) SYSTEMS:

In Command prompt type "ntpdate -u server address".

In graphics mode double click at time, tick “Automatically Synchronize with NTP server”

option.

Enter your NTP server address click Update Now.

And give “OK”.

Your system should get synchronized.

WARRANTY

What does this warranty cover?

This Warranty applies to all Sertels products purchased from an authorized OEM to the

original purchaser for normal use and not for resale. SERTEL warrants that a covered

product is free from defects in materials and workmanship, with the exceptions stated

below.

How long does limited warranty coverage last?

This warranty lasts for 1 year from originally purchased date. A valid proof of purchase

may be required to prove eligibility. If you do not have a valid proof of purchase, the

warranty period will be measured from the date of sale from Sertel Electronics to the

OEM.

What does this warranty not cover?

The warranty does not cover damage resulting from commercial use, misuse, accident,

modification or alteration to hardware or software, tampering, unsuitable physical or

operating environment beyond product specifications, improper maintenance, or failure

caused by a product for which SERTEL Electronics is not responsible. There is no

warranty of uninterrupted or error-free operation.

There is no warranty for product with removed or altered identification labels. Sertel

does not provide any other warranties of any kind, including, but not limited to, the

implied warranties or conditions of merchantability and fitness for a particular purpose.

some jurisdictions do not allow the limitation of implied warranties, so this limitation

may not apply to you. Sertel is not responsible for replacing the product which is not

covered by this warranty.

What must you do?

If you are having trouble with a product, before seeking warranty service, first follow the

troubleshooting procedures that SERTEL provides.

To obtain warranty service, please email sales@serteltelser.com. All associated

transportation charges, duties and insurance in shipping the drive to our logistics center

at your cost. You should remove all personal information from the product prior to its

return.

How is our liability limited?

Sertel and its affiliates, suppliers, distributors, and resellers are not liable for any of the

following:

1) Third-Party Claims Against You For Damages

2) Loss of, or damage to, your data; or

3) special, incidental, or indirect damages or for any economic consequential damages

(including lost profits or savings), even if informed of the possibility. some jurisdictions

do not allow limitation of liability, incidental damages, or consequential damages, so the

above limitations may not apply to you.

AFTER SALES SERVICE Please contact sales@serteltelser.com or info@sertelteser.com for further details.