2017-04-05

Next Generation Beacons

GPSDO/GPS reference setup


Overview VCO-PLL DDS GPS reference Distribution amplifiers Service management Sequence PI4 Software

Setting up a Jupiter TU30 GPS to be used in the Next Generation Beacons platform.

This documents describes how to setup/change a Jupiter TU30 GPS receiver so it can be used in the Next Generation Beacons platform: www.rudius.net/oz2m/ngnb/gps

There are at least three ways you can perform the necessary changes.

  1. Using BeaconManager

  2. Using a terminal program, e.g. Realterm, that can send binary files

  3.  Using WinLabMon that may have issues on certain Windows installations

Before starting the S/W configuration please verify that the headers on SW1, SW2 and SW3 are located to the left when the BNC, opto transmitters and USB port are facing you.

Method 1

Just connect and click either the Config 4k8 or the Config 9k6 buttons in BeaconManager.

Method 2

Please download and unzip the command files.

Changing the output data

The process is divided into

Identify the COM port where the GPS is connected

From the Menu | Com select the COM port and speed you think the GPS is using. If you are in doubt about the COM port use the Windows Control Panel to find out which COM port is used.

Force the GPS to run in NMEA mode

Start your favorite terminal program capable of sending binary files and connect to the relevant COM port and at the relevant speed. You may see a lot of gibberish in case the GPS is already in binary mode. It may be a bit tricky to identify at which speed the GPS runs, e.g. 4800 Baud, 9600 Baud … so you may have to try several speeds. You may have to disconnect and connect to the GPS in the terminal program every time you change speed.

To change data format to NMEA send the Binary_to_NMEA.dat file to the GPS.

You will have to repeat both of the above steeps until you see plain ASCII NMEA data strings. Do not proceed until this is the case.

Force the GPS to run in binary mode

Send the NMEA_to_binary.dat file to the GPS. Gibberish should be visible when the GPS is in binary mode.

Changing data format and speed

Send Binary_to_9600_Baud.dat file to the GPS.

The GPS is now outputting binary messages at 9600 Baud.

To change data format from binary to NMEA send the Binary_to_NMEA.dat file to the GPS at the right Baud rate.

The GPS is now outputting all NMEA messages it is able to at 9600 Baud.

Disable irrelevant messages and enable $GPRMC

The Next Generation Beacons platform must only receive the $GPRMC frame.

First you must disable all NMEA strings. Do this by sending the NMEA_disable_all.dat file to the GPS.

Then enable the $GPRMC message by sending the NMEA_enable_GPRMC.dat file to the GPS.

The setup of the GPS has been completed and the data format is NMEA and at 9600 Baud and only the $GPRMC string is being sent. It might be relevant to change settings in the DDS unit too, e.g. the GPS speed, address 1e, and the GPS 1 PPS to NMEA delay, address 1f.

Method 3

Changing the output data

With the programs installed, the headers in place and the GPSDO connected to a PC the protocol and serial speed of the GPS data output can now be changed.

The process is divided into

Identify the COM port where the GPS is connected

From the Menu | Com select the COM port and speed you think the GPS is using. If you are in doubt about the COM port use the Windows Control Panel to find out which COM port is used.

If you are in doubt if this is the GPS then disconnect and re-connect the GPS to see which COM device disappears and re-appears.

WinLabMon can only work with COM1 to COM4. So if the detected COM port is different from this then also the COM port number has to be changed. This can be done by double clicking the relevant COM port in the Device Manager and the following window will appear.

On the Port Settings tabsheet click the Advanced button and the following window will appear.

Then change the COM Port Number to COM1, COM2, COM3 or COM4. The latter is recommended even if it is “(in use)” already. When done press OK and close the Device Manager windows.

Force the GPS to run in binary mode

Start WinLabMon.

In WinLabMon Menu | Options | WinLabMon | GPS Data select the Binary GPS data format. Do this even if the GPS uses NMEA already.

In the I/O tabsheet set the Baud rate to 9600 Baud and set the BUS to RS232.

Click the OK button.

Select Menu | File | Run. If it is Run already select Stop and then Run. The red square should change to green and data strings will be visible. If not repeat above steps to identify the current data format and serial speed.

Changing data format and speed

To change data format and speed, from any current mode, the GPS must first be set to binary mode. Do this from Menu | SetRcvr. If SetRcvr is grayed out the one of the steps in the “Force the GPS to run in binary mode” section did not work out right.

Then change the speed, from the same menu, to 9600 Baud.

Then change the data format to NMEA.

The GPS is now outputting all NMEA messages it is able to at 9600 Baud. WinMonLab can be closed from Menu | File | Exit. If WinLabMon is closed at the [X] button at the top right corner it remains running until it is terminated via the Windows Task Manager.

Disable irrelevant messages and enable $GPRMC

The Next Generation Beacons platform must only receive the $GPRMC frame.

Start a terminal program and set it up for 9600 Baud, 8N1 and set transmitted text to “Append CR-LF” (for any other Next Generation Beacons device this must always be “Append LF” only).

Now send the following string to the GPS to stop all NMEA output:

$PRWIILOG,???,V,,,

Then send the following string to the GPS to enable the $GPRMC frame:

$PRWIILOG,RMC,A,T,1,0

The setup of the GPS has been completed and the data format is NMEA and at 9600 Baud and only the $GPRMC string is being sent. It might be relevant to change settings in the DDS unit too, e.g. the GPS speed, address 1e, and the GPS 1 PPS to NMEA delay, address 1f.


Bo, OZ2M, www.rudius.net/oz2m