Toshiba HHGP1 User Manual

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INSTRUCTION MANUAL

GPS RECEIVER UNIT

HHGP1

( Ver. 1.6 )

Safety Precautions

Before using this product, please read this chapter carefully.

This chapter describes the safety precautions recommended when using the GPS receiver unit type HHGP1. Before installing and using the equipment, this chapter must be thoroughly read and understood.

Explanation of symbols used

Signal words such as DANGER, WARNING, and two kinds of CAUTION, will be followed by important safety information that must be carefully reviewed.

Indicates an imminently hazardous situation which will result in death or

DANGE

Indicates a potentially hazardous situation which could result in death or

WARNING

serious injury if you do not follow the instructions.

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CAUTION Indicates a potentially hazardous situation which if not avoided, may result in

minor injury or moderate injury.

CAUTION Indicates a potentially hazardous situation which if not avoided, may result in

property damage.

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DANGE

• Installing arrester

Install a surge arrester between the antenna and the GPS receiver and ground it in accordance with the guidelines in this manual. Otherwise, it may cause electric shocks, injury or malfunction.

WARNING

• Exposed terminals

Do not touch the terminals of this equipment while the power is on, as the high voltage generated is dangerous.

• Residual voltage

Hazardous voltage can be present in the DC circuit just after switching off the DC power supply. It takes approximately 30 seconds for the voltage to discharge.

• Fibre optic

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When connecting this equipment via an optical fibre, do not look directly at the optical signal.

CAUTION

• Earth

The earthing terminal of the equipment must be securely earthed.

CAUTION

• Operating environment

The equipment must only used within the range of ambient temperature, humidity and dust detailed in the specification and in an environment free of abnormal vibration.

• Ratings

Before applying the DC power supply to the equipment, check that they conform to the equipment ratings.

• Connection cable

Carefully handle the connection cable without applying excessive force.

• Modification

Do not modify this equipment, as this may cause the equipment to malfunction.

• Disposal

When disposing of this equipment, do so in a safe manner according to local regulations.

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Contents

Safety Precautions 1

1. Introduction 5

2. Characteristics 5

3. Configuration 6

3.1 Configuration of GPS Receiver Unit 6

3.2 Outline of GPS Receiver Unit and Function 7

4. Handling 8

4.1 Setting the GPS Receiver Unit 8

4.2 How to Turn on the Power 9

4.3 Checking the 1PPS Signal 9

5. Operation 10

5.1 1PPS Signal Output 10

5.2 Time Data Output 11

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6. Installation 12

6.1 Receipt of GPS Receiver Unit 12

6.2 Installing GPS Receiver Unit 12

6.3 Installing Antenna 12

6.4 Installing Surge Arrester 15

6.5 Installing Fibre Optics 15

6.6 Connecting the Power Supply and the Earthing Terminal 16

7. Preparation for Installation 17

7.1 Selecting an Antenna and Cables 17

7.2 Selecting Coaxial Cables and Conversion Adapters 17

7.3 Selecting an Antenna Installation Location 18

8. Maintenance 19

8.1 Regular Maintenance 19

8.2 Troubleshooting 19

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Appendix A Outline of GPS Rceiver Unit 21

Appendix B Technical Data 23

Appendix C Specification of Recommended Antenna and Arrester 27

Appendix D Supplement 31

 The data given in this manual are subject to change without notice. (Ver. 1.6)

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1. Introduction

The GPS (Global Positioning System) receiver unit is a device that receives the information from satellites and outputs time signals synchronous to UTC (Universal Coordinated Time) to external devices. The GPS receiver unit provides multiple outputs with optical signals for noise immunity.

2. Characteristics

■ Highly accurate time signal output

Realizes a precision with respect to ±2µs for UTC (UTC: Universal Coordinated Time)

(excluding the propagation delay time on the cable).

■ Reduced cabling work

Adopting the signal superimposition method, the unit can be connected to an external device

with a single optical fibre only.

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■ Application to a large system

Equipped with eight ports for output, the time distribution can be made to multiple devices

separated from each other by a maximum of 1 km.

■ High reliability

Aimed at reducing the number of parts through high-integration circuits and high-density

mounting technology, thus securing high reliability.

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3. Configuration

3.1 Configuration of GPS Receiver Unit

Figure 3.1.1 shows the configuration of the GPS receiver unit.

The GPS receiver unit receives electromagnetic signals from satellites through an antenna and outputs time data to external devices. Through an internal receiver, the unit generates serial time data and 1-second pulses (1PPS signals), based on the received electromagnetic signal. Each 1PPS signal occurs at the instant in time given by its accompanying frame of serial data.

To reduce the number of cables to external devices, time data and 1PPS signals are superimposed through a mixing circuit before being output to the optical fibre.

Antenna

Receiver

Time data

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Backup

Capacitor

1 Pulse per second (1PPS)

Mixing Circuit

E/O

E/O E/O E/O

E/O E/O E/O E/O

Electrical-to-optical Converter

Fibre-optic Cable

Power supply

+48V

Noise

Filter

DC/DC

+5V

Converter

Figure 3.1.1 Configuration of GPS Receiver Unit

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3.2 Outline of GPS Receiver Unit and Function

Figure 3.2.1 shows outline and functions of GPS receiver unit.

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FRONT VIEW

REAR VIEW

⑧

⑤

④

②①③

⑥

⑦

48V

No. Device Indication Functions

Yellow LED 5 V Turns on when the power (5Vdc) is supplied.

①

Yellow LED 1PPS OUT Blinks when 1PPS signals are output synchronously with UTC.

②

Red LED ERROR Turns on when the internal crystal oscillator stops.

③

DIP switches DSW Set the GPS receiver unit settings. During operation, these DIP

④

switches are covered to prevent erroneous operations.

Signal output ports OPT.OUT Outputs time signals. The optical fibre is connected here.

⑤

Power supply switch INPUT Turns on or off the power of the GPS receiver unit.

⑥

Terminal block __ The 48V dc power is applied and the earth cable is connected.

⑦

P: 48Vdc, N: 0Vdc, E: earth

Antenna terminal ANT.IN The antenna cable is connected.

⑧

Figure 3.2.1 Outline and Functions of GPS Receiver Unit

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4. Handling

4.1 Setting the GPS Receiver Unit

The GPS receiver unit is set in accordance with the requirements of the system by using the DIP switches located on the front panel of the unit.

To prevent erroneous operations, the DIP switches are protected with a cover. As shown in Figure 4.1.1, when the cover is rotated after loosening the cover screw with a screwdriver, the switches are exposed thus making it possible to handle them. Switches are handled with a sharp-pointed object such as a screwdriver and set to “ON” or “OFF” by pushing them up or down respectively. After accessing the switches, tighten the cover screw to its original state.

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DSW

Figure 4.1.1 Switch Operation Method

Four switches are numbered 1 to 4 from left to right. (The numbers are indicated on their respective switches.)

Table 4.1 shows the function and setting of each switch. (All the switches are set to “OFF” for default setting.)

１２３４

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Table 4.1 Setting the Switches

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Switch

No.

1 Location mode

2 Reliability/TRAIM

3 Optical level test Continuous light emission Normal light emission

4 Clock range

Function

ON OFF (default)

Location fixing mode Location estimation mode

change

Normal/TRAIM OFF High-reliability/TRAIM ON

mode change

2020 – 2039 (Year) 2001 – 2019 (Year)

change

Setting

Note: Settings can be changed when the power is ON, but changes are not valid until the

power has been switched OFF and ON again, except in the case of switch 3 for optical level testing, which is valid immediately.

- In the case of location mode, the location estimation mode (OFF) should be used.

- In the case of reliability/TRAIM, the High-reliability/Train ON mode (SW-OFF)

should be used.

- In high-reliability mode, the unit outputs the 1PPS signal only when no failed

satellites are detected. In the case of two or more failed satellites, correct operation of the unit cannot be assured.

- In the case of clock range change, the switch should be OFF before 2019 and ON

after 2020.

For the details, see the Appendix D.

4.2 How to Turn on the Power

Turn on the power switch. Power ON is confirmed by the illumination of the "5V" LED on the front panel of the unit.

4.3 Checking the 1PPS Signal

After the power is turned on, check that 1PPS signals are output. If 1PPS signals are not output, it is impossible to use the time signals that are output from the GPS receiver unit. Output of 1PPS signals is confirmed by the blinking of the "1PPS OUT" LED on the front panel of the unit.

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5. Operation

5.1 1PPS Signal Output

The GPS receiver unit outputs 1PPS signals with each pulse defining the instant of time described by the preceding frame of serial data. (For the time signal transmission format, refer to Appendix D.)

Following power-up, the GPS receiver begins outputting 1PPS signals after the acquisition of the almanac data and the estimation of the receiver location (or the antenna location to be more exact) are completed.

Almanac data received from the satellites include satellites outline orbit information and UTC time correction parameters. It takes about 12 to 30 minutes to acquire the data.

The almanac data is backed up temporarily following power-down. If power is removed for 16 hours or more, then the data back-up may be lost and will have to be re-acquired on power-up.

If the almanac data back-up is valid on power-up, acquisition of almanac data is unnecessary.

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To estimate the location, signals from four or more satellites are required in the case of normal mode; and five or more are required in the case of high-reliability mode.

Note: If the antenna is positioned in the shade of buildings, or in other locations where it is difficult to

receive satellite signals, then location estimation may take a longer time or may even be impossible.

If satellites are closely aligned in relation to the receiver, then it may not be possible to achieve

a location estimate, even when the necessary numbers of signals are received. The reason for this is that, as the angle between received signals becomes small, the error in location estimation becomes large.

Accordingly, installing an antenna in a location of narrow visual field such as between tall

buildings may make the location estimation impossible. When using the high-reliability mode and/or TRAIM function, the alignment of satellites has even stricter limits.

The location estimation may take more than an hour depending on constellation of satellites in

case of the high-reliability mode.

The location estimation is required each time the power is turned on.

After the location estimation is completed, the 1PPS signal is output in normal mode if signals from one or more satellites are received; and two or more in high-reliability mode.

The initialization time for the 1PPS signal at power-up varies as shown in Table 5.1.1, depending on the state of the almanac data back-up.

Table 5.1.1 1PPS Output Start Time

Back up of almanac data Initial time needed for 1PPS signal output from power on

Lost 30 seconds to 1 hours (*1)

Available 10 seconds to 1 hours (*1)

(*1) It may take further time depending on constellation of satellites and antenna position.

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