GeoSIG GMS-TIM GMS and GPS Receiver Module

Product Information

The GMS-TIM is a timing receiver box manufactured by GeoSIG Ltd. It offers concurrent reception of up to 3 GNSS (GPS, Galileo, GLONASS, BeiDou) signals. The device is designed to provide accurate timing information and is equipped with RS-232 and RS-485 cables for electrical connection.

Disclaimer
GeoSIG Ltd reserves the right to change the information contained in this document without notice. While the information contained herein is assumed to be accurate, GeoSIG Ltd assumes no responsibility for any errors or omissions.
Copyright Notice
No part of this document may be reproduced without the prior written consent of GeoSIG Ltd. Software described in this document is furnished under a license and may only be used or copied in accordance with the terms of such a license.
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All brand and product names mentioned are trademarks or registered trademarks of their respective holders.
All rights reserved.
GeoSIG Ltd
Switzerland

Document Revision

Version	Date	Modification	Prepared	Checked	Released
0	2023-10-03	First issue	KEC	TAB	ALB

Warnings and Safety 

• The GPS system is operated by the government of the United States of America, which is solely responsible for its accuracy and maintenance.
• GPS provides only UTC time at 0° Greenwich meridian without daylight savings time adjustment.
• GMS-TIM offers concurrent reception of up to 3 GNSS (GPS, Galileo, GLONASS, BeiDou).

Symbols and Abbreviations 

• Instrument: GeoSIG Recorder, Digitiser or Data Acquisition system
• GPS: Global Positioning System
• UTC: Universal Time Clock

Introduction

This document describes the principle of operation and installation instructions of the timing receiver. The timing receiver is used with GeoSIG Instruments to provide the accurate date and time to the Instruments and the GNSS coordinates of the antenna. It’s very useful for precise synchronization of one or several interconnected Instruments.

• GNSS provides only UTC time at 0° Greenwich meridian without daylight savings time adjustment.

The timing receiver is provided in a box with a cable length to be defined at the time of order or provided by the customer.

GMS-TIM Cable

Two different cables can be used according to connection:

• GPS – RS-232 (standard): Up to 70 meters of cable length
• GPS – RS-485: Up to 300 meters of cable length

RS-232 cable 

For the RS-232 connection, the cable used by default is: GeoSIG standard cable type: XY DIN 5 x 0.25 mm2 gr UL style 2464.

RS-485 cable

For the RS-485 connection, the cable used by default is: GeoSIG standard cable type: LiY(St)CY 300V 4 x 2 x 0.25 mm2 gr UL Style 2464.

Mounting the Timing Receiver Box

It is recommended to perform a check of the GNSS function before mounting the box to its final location, as described in section 5.  The timing receiver device box can be fixed to various locations. The position of the box should be defined according to a position where the antenna can easily get the satellite signals. Typically, the box is fixed on an outside wall or on a roof. This is an important point as the antenna should receive signals from at least 3 satellites for synchronisation of the instrument. Make sure that at least 75% of the sky is visible at all times over the timing receiver box.  Fixation of the housing should be done with M4 screws with spacing and locations as shown in Figure 3 and Figure 4. Type of screw depends on the type of surface where the box will be fixed.

Electrical Connection

Timing Receiver Main Connector Pin Assignment

1. With RS-232 connection
   The device is provided with an 8-pin main connector inside the box, supplied already connected.
   Table 1. Electrical connections of the RS-232 timing receiver connector

   Pin	Signal	Standard cable Colours	Comment
   1	GPS_RX_P	White	Reception signal from instrument
   2	GPS_TX_P	Brown	Transmit GNSS signal
   3	GPS_1PPS_P	Green	1 PPS signal of GNSS
   4	V_MAIN	Yellow	12V power from instrument
   5	GPS_1PPS_N	N/A	Only used for RS-485
   6	GND	Grey	Ground from instrument
   7	GPS_RX_P	N/A	Only used for RS-485
   8	GPS_TX_N	N/A	Only used for RS-485

   
2. With RS-485 connection
   The device is provided with an 8-pin main connector inside the box, supplied already connected.
   Table 2. Electrical connections of the RS-485 timing receiver connector

   Pin	Signal	Standard cable Colours	Comment
   1	GPS_RX_P	White	Reception signal from instrument+
   2	GPS_TX_P	Green	Transmit signal of GNSS+
   3	GPS_1PPS_P	Grey	1 PPS signal of GNSS+
   4	V_MAIN	Red	12V power from instrument
   5	GPS_1PPS_N	Pink	1 PPS signal of GNSS-
   6	GND	Blue	Ground from instrument
   7	GPS_RX_N	Brown	Reception signal from instrument-
   8	GPS_TX_N	Yellow	Transmit signal of GNSS-

   

Mating Connector at the Instrument Side
A mating connector must be used for connecting the timing receiver to an Instrument. This connector is already assembled when the timing receiver is ordered together with the Instrument.

1. GXR-XX Device 
   1. Mating Connector at the Instrument Side for RS-232 connection
      Table 3. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_RXD	White	Transmit signal of GSR
      2	GPS_TXD	Brown	Reception signal of GSR
      3	GPS_STDBY	N/A	Not connected
      4	GND	N/A	Not connected
      5	GPS_1PPS	Green	1 PPS signal from GPS
      6	V_MAIN	Yellow	12V power from instrument
      7	GND	Grey	Ground from instrument

      

   2. Mating Connector at the Instrument Side for RS-485 connection
      Table 4. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	N/A	N/A	Not connected
      2	SYNCI_RX+	White	GNSS Transmit signal+
      3	N/A	N/A	Not connected
      4	SYNCI_RX-	Brown	GNSS Transmit signal-
      5	GPS_1PPS	Green	1 PPS signal from GNSS
      6	V_EXT_GPS	Yellow	12V power from instrument
      7	GND_EXT	Grey	Ground from instrument

      

2. GMS Devices
   This includes the instruments GMS-XX and GMSplus.
   1. Mating Connector at the Instrument Side for RS-232 connection
      Table 5. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_RXD	White	Reception signal from instrument
      2	GPS_TXD	Brown	Transmit signal of GNSS
      3	GPS_STDBY	N/A	Not connected
      4	GND	N/A	Not connected
      5	GPS_1PPS	Green	1 PPS signal from GNSS
      6	V_MAIN	Yellow	12V power from instrument
      7	GND	Grey	Ground from instrument

      

3. scai – GMS series or nair – GMS series Device 
   1. Mating Connector at the Instrument Side for RS-232 connection
      Table 6. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_1PPS+	Green	1 PPS signal from GNSS
      2	GPS_1PPS-	N/A	Not connected
      3	TX+	Brown	Transmit signal of GNSS
      4	TX-	N/A	Not connected
      5	RX+	White	Reception signal from instrument
      6	RX-	N/A	Not connected
      7	SUPPLY+	Yellow	12V power from instrument
      8	SUPPLY-	Grey	Ground from instrument

      

   2. Mating Connector at the Instrument Side for RS-485 connection
      Table 7. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_1PPS+	Grey	1 PPS signal from GNSS (positive)
      2	GPS_1PPS-	Pink	1 PPS signal from GNSS (negative)
      3	TX+	Green	Transmit signal of GNSS (positive)
      4	TX-	Yellow	Transmit signal of GNSS (negative)
      5	RX+	White	Reception signal, GNSS (positive)
      6	RX-	Brown	Reception signa, GNSS (negative)
      7	SUPPLY+	Red	Supply positive (12V power)
      8	SUPPLY-	Blue	Supply negative (Ground)

      

4. CR-5 Device (legacy) 
   1. Mating Connector at the Instrument Side for RS-232 connection
      Table 8. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_1PPS+	Green	1 PPS signal from GNSS
      2	TX+	Brown	Transmit signal of GNSS
      3	RX+	White	Reception signal from instrument
      4	SUPPLY+	Yellow	12V power from instrument
      5	SUPPLY-	Grey	Ground from instrument

      

5. CR-6 / CR-6plus Device (legacy)
   1. Mating Connector at the Instrument Side for RS-232 connection
      Table 9. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	RX+	Brown	1 PPS signal from GNSS
      2	TX-	White	Transmit signal of GNSS
      3	GPS_1PPS	Green	Reception signal from instrument
      4	V_EXT_GPS	Yellow	12V power from instrument
      5	GND_EXT	Grey	Ground from instrument

      

   2. Mating Connector at the Instrument Side for RS-485 connection
      Table 10. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	RX+	White	1 PPS signal from GNSS
      2	RX-	Brown	Transmit signal of GNSS
      3	GPS_1PPS	Green	Reception signal from instrument
      4	V_EXT_GPS	Yellow	12V power from instrument
      5	GND_EXT	Grey	Ground from instrument

      
6. fora – CR series Device
   1. Mating Connector at the Instrument Side for RS-232 connection
      Table 11. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_1PPS+	Green	1 PPS signal from GNSS
      2	GPS_1PPS-	N/C	Not connected
      3	TX+	Brown	Transmit signal of GNSS
      4	TX-	N/C	Not connected
      5	RX+	White	Reception signal from instrument
      6	RX-	N/C	Not connected
      7	SUPPLY+	Yellow	12V power from instrument
      8	SUPPLY-	Grey	Ground from instrument

      
   2. Mating Connector at the Instrument Side for RS-485 connection
      Table 12. Electrical connections of an Instrument’s timing receiver input connector

      Pin	Signal	Standard Cable Colours	Comment
      1	GPS_1PPS+	Grey	1 PPS signal from GNSS (positive)
      2	GPS_1PPS-	Pink	1 PPS signal from GNSS (negative)
      3	TX+	Green	Transmit signal of GNSS (positive)
      4	TX-	Yellow	Transmit signal of GNSS (negative)
      5	RX+	White	Reception signal, GNSS (positive)
      6	RX-	Brown	Reception signa, GNSS (negative)
      7	SUPPLY+	Red	Supply positive (12V power)
      8	SUPPLY-	Blue	Supply negative (Ground)

      

Configuration and Checking

With a GXR-XX
In order to synchronize a GeoSIG GSR-xx with the GNSS, appropriate configuration should be made in the Instrument. Once power supply, computer and GPS are connected to the Instrument, such configuration and checks can be performed by logging into the Instrument using GeoDAS.

• For more details about the GNSS options, please consult GeoDAS and relevant Instrument manuals.
• At first installation or after a major (>2’000 km) relocation, it may take up to 5 minutes for the GNSS to correctly compute the exact location of the antenna.

The following is a brief instruction to check whether everything is operational in terms of the GNSS: On the “Instrument” tab, the “Garmin GPS” option should be ticked as a peripheral device, as shown on Figure 29. On the “Date and Time” tab, as shown on Figure 30, GPS status should read “Enabled”; if not, press the “Enable GPS” button.
Note that if GPS is enabled, this button reads “Disable GPS”.

When GNSS is synchronized, the date and time of the GNSS can be seen in the “Date and Time” tab and the global coordinates of the antenna can be seen in the “Station” tab, as shown on Figure 31.

With a GMS-XX or a GMSplus or a scai or a nair

1. Configuration of GPS
   In order to synchronize a GeoSIG GMS-xx, GMSplus, scai or nair with the GNSS, appropriate configuration should be made in the Instrument. Once power supply, computer and GNSS are connected to the Instrument, such configuration and checks can be performed by logging into the Instrument using GeoDAS.
   In the Web Interface:
   • Go to Configuration
   • In Data Acquisition tab go to Miscellaneous Parameters
   • Go to Time synchronization
   • In Time synchronization menu shown in Figure 32, change the Time source to GPS
   • Configure the options if necessary
   • Finally click on Apply and Restart to apply the latest options to the device
     Some GPS options should be updated if necessary; the web interface offers some information about these options.
     Click on this icon next to the option to see a summary of the option
     GPS configuration is explained in detail in the time synchronization subchapter of the User Manual.
2. Check GPS data
   In order to verify the GPS in a GeoSIG GMS-xx, GMSplus, scai or nair, an appropriate configuration should be made in the Instrument. Once power supply, computer and GPS are connected to the Instrument, such checks can be performed by logging into the Instrument using GeoDAS.
   In the Web Interface:
   • Go to Status and Maintenance→ Recording Status tab
   • Check data in the Synchronisation Status panel shown in Figure 33

With a CR-5P (legacy)
In order to synchronize a GeoSIG CR-5P (legacy) with the GPS, an appropriate configuration should be made in the Instrument. Once power supply, computer and GPS are connected to the Instrument, such configuration and checks can be performed by logging into the Instrument using GeoDAS.

• For more details about the GPS options, please consult GeoDAS and relevant Instrument manuals.
• At first installation or after a major (>2’000 km) relocation, it may take up to 5 minutes for the GPS to correctly compute the exact location of the antenna.

The following is a brief instruction to check whether everything is operational in terms of the GPS:

• While adding the CR-5P under “Channels of Digitizers”, make sure ‘External SYNC Signal’ is selected as Time source, as shown in Figure 34.
• After adding the CR-5P to GeoDAS, restart the software; the window “Stations: Data Stream” will appear.
• When GPS is synchronized, the ‘GPS status’ will read “Locked to GPS”, as shown in Figure 35. The data stream in the ‘Data Monitor’ will be in yellow, as shown in Figure 36.

Note that if no GPS is connected, GPS status will read “No Lock” and the colour of the data stream will be white.

With a CR-6/CR-6plus (legacy) or a fora – CR series

1. Configuration of GPS
   In order to synchronise a GeoSIG CR-6/CR-6plus (legacy) or fora – CR series with the GPS, an appropriate configuration should be made in the Instrument. Once power supply, computer and GPS are connected to the Instrument, such configuration and checks can be performed by logging into the Instrument using GeoDAS.
   In the Web Interface
   • Go to Configuration
   • In Data Acquisition tab go to Miscellaneous Parameters
   • Go to Time synchronization
   • In Time synchronization menu shown in Figure 37, change the Time source to GPS
   • Configure the options if necessary
   • Finally click on Apply and Restart to apply the latest options to the device
     Some GPS options should be updated if necessary; the web interface offers some information about these options.
     Click on this icon next to the option to see a summary of the option
     GPS configuration is explained in detail in the Time synchronization subchapter of the User Manual.
2. Check GPS data
   In order to verify the GPS in a CR-6/CR-6plus (legacy) or fora – CR series, appropriate configuration should be made in the Instrument. Once power supply, computer and GPS are connected to the Instrument, such checks can be performed by logging into the Instrument using GeoDAS.
   In the Web Interface:
   • Go to Status and Maintenance→ Recording Status tab
   • Check data in the Synchronisation Status panel shown in Figure 38

Documents / Resources

GeoSIG GMS-TIM GMS and GPS Receiver Module [pdf] User Manual GMS-TIM, GMS-TIM GMS and GPS Receiver Module, GMS and GPS Receiver Module, GPS Receiver Module, Receiver Module, Module

References

• User Manual