What is the difference between an LD3 and an LD3S?

More recent LD3 units use a second generation L-band card. They are identified with an “S” suffix in the model number (e.g. LD3S-G1 instead of LD3-G1).

A software application VERIPOS LBand Control was introduced to allow configuration of both types of units. 

In the opening dialog, the user is required to select the appropriate receiver type based on the L-band installed in the unit:

Select the Rx Type from the drop down list.

• For LD3 or LID3 units, select Racal OEM
• For LD3S or LID3S units, select Septentrio LBR

Select the appropriate PC COM port from the drop down list then click OK

When connection is established the Welcome screen will display the serial number and firmware versions of the receiver:

A typical display for an LD3 or LID3

A typical display for an LD3S or LID3S

The two software versions use slightly different menus (the latest issue of the Operations Manual has two separate sections under Unit Configuration).

For users already familiar with the LD3, the main difference encountered when operating the LD3S is that the unit cannot be enabled or disabled until it has locked to the L-band signal (Sync indicator illuminated).

On the LD3, the ID indicator was always either flashing (disabled) or steadily illuminated (enabled).

On the LD3S, the indicator will be extinguished when the unit is first turned on. It will not be illuminated until the unit has locked to the L-band signal (“Sync” indicator illuminated). It will then either be flashing (disabled) or steadily illuminated (enabled).

If it is necessary to perform advanced configuration of the GPS receiver using Ashtech Evaluate software, the user must also be aware that the GPS receiver ports are connected differently on the two units:

For LD3 units:

• Port A is connected to the rear panel and is used for NMEA output.
• Port B is connected to the front panel and is used for GPS I/O.

For LD3S units:

• Port B is connected to the rear panel and is used for NMEA output.
• Port A is connected to the front panel and is used for GPS I/O.