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GPS Clock Hardware Manual

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GPS Clock

Global Positioning System (GPS) Clock


The Galleon GPS Clock receives time and positioning information from Global Positioning Satellites, which can be used to accurately synchronise the time on computers.

The Galleon GPS clock has a number of advantages over similar radio based products. It can be used at any location all around the world; radio broadcasts have a strictly limited range. The GPS clock is less susceptible to interference. Provided the GPS antenna has a clear view of the sky, it is less prone to environmental obstructions.

The GPS clock receives UTC time from the Global Positioning Satellites. UTC time is the same all around the world. The clock makes no adjustment for British Summer Time (BST). This is not a problem since the host computer can make local time zone or daylight saving time adjustments.

The GPS Clock Unit

The GPS clock can be divided into three distinct parts: antennae, receiver unit and microcontroller interface. Additionally, there is a connector box between the receiver and microcontroller units for ease of installation.

12V DC power supplies power the connector box and microcontroller interface units.

GPS Antenna


The Antenna can be mounted either with a suction cup mount or a magnetic mount; both are included with your antenna.

Whatever mounting method you choose, you must ensure that the antenna�s location provides an unobstructed view of much of the sky. This is critical because the antenna must �see� at least four satellites well in order for the system to operate.

Using the Antenna Mount

Attach the magnetic mount to the bottom of the antenna using the two M3 flat head screws provided. The antenna will now mount to a flat ferrous metal surface.

Note: Do not use the magnetic mount in areas near a directional compass. Aircraft applications should use another mounting method.

Using the Suction Cup Mount

Attach the suction cup mount to the bottom of the antenna using the two M3 flat head screws provided. Use suction cups to hold antenna. The suction cup mount can be adjusted to compensate for the different angles, as required. Rotating the large suction cup makes the adjustment.

GPS Receiver Unit

The GPS receiver is contained in a grey waterproof enclosure. If mounted externally it is advisable to locate the unit in a shaded position to avoid overheating.

Connector Box

The connector box is used to facilitate installation of the GPS Clock. It provides a screw terminal connector for cabling to the Microcontroller interface unit. The cable from the connector box to the microcontroller unit requires at least six cores and can be up to 1Km in length. Suitable cable can be obtained from Galleon systems, if required.

Microcontroller Unit

The microcontroller unit should be sited suitably close to the host computer. It must be powered by the 12V DC power supply provided. A female 9 pin �D� type connector is provided for connection to the serial port (RS232) of the host computer. A connector box is located at the back of the unit for cabling from the receiver connector box.

Important Note: Ensure that the GPS receiver unit is powered on before powering on the Microcontroller unit. This is necessary because the microcontroller unit configures the GPS receiver on power up,

Green LED

The Green LED when on indicates that the GPS clock is waiting for the receiver to lock on to enough satellites to provide the unit with a valid time. On first installation this may take a period of time.

When the GPS Clock has locked on to the satellites and a valid time has been established, the Green LED will go out. Thereafter, as long as enough satellites are available the Green LED will flash approximately once per minute.


The Red LED should flash at approximately 1-second intervals to indicate that serial data is being sent from the GPS receiver. If the Red LED is not flashing ensure that the GPS receiver unit is powered on. Also, check the cabling between the GPS receiver unit and the Microcontroller Unit.

Receiver and Microcontroller Connector Box Cabling

The connectors in the Receiver Connector Box and the Microcontroller Connector Box are numbered 1 to 6. Ensure that the connections are 1 to 1, 2 to 2, 3 to 3, 4 to 4, 5 to 5 and 6 to 6.

GPS Clock Installation

Antenna must have clear view of sky in all directions

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