Satellite-Based Augmentation System (SBAS)

The 3DM-GQ7 supports user configurable SBAS corrections with the following options:

1. Enable Flag - This flag will enable/disable the SBAS subsystem for each GNSS receiver. If your application prohibits the use of SBAS, setting this option to "0" (disabled) will ensure no SBAS corrections will be generated or utilized.

2. SBAS Options Bitfield - This bitfield allows users to customize how the SBAS corrections are used by the GNSS receivers and the tightly-coupled filter. The following bits are defined:

0x0001 - Ranging: Enables/disables the use of SBAS pseudoranges as part of the GNSS receiver solution. Note: the tightly-coupled solution will not utilize SBAS pseudoranges even if this bit is set.

0x0002 - SBAS correction data: Enables/disables the use of SBAS corrections in both the GNSS receiver solution and tightly-coupled solution. Note: this bit has a similar effect to the enable flag above, but does not disable the SBAS subsystem.

0x0004 - Apply integrity information: Enables/disables the use of SBAS integrity information as part of the GNSS receiver solutions. . Note: the tightly-coupled solution will not utilize SBAS integrity information even if this bit is set. In addition to GNSS satellite corrections, SBAS provides integrity information that can be used to further restrict when satellites and signals are used. These features of SBAS were designed with certified aircraft operations in mind. Generally speaking, it is not necessary to enable this feature, but if it is enabled, note that it may restrict the available signals used by the GNSS module solution.

3. Satellite PRN List - This is a list of satellite PRNs to include when the GNSS receivers search for a SBAS satellite. Only one SBAS satellite is selected for correction/integrity information at any given time. If ranging is enabled, ranging from all visible SBAS satellites will be used in the GNSS receiver solution. A user may wish to limit the usable SBAS satellites when they are in geographical regions where satellites are visible that will not provide correction data for the operational area. This can happen in the Eastern parts of North America, where EGNOS satellites may be in view, but these satellites only provide ionospheric corrections for Europe. The same is true for Western Europe where WAAS satellites may be in view, but only provide ionospheric corrections for North America. Note: A count of 0 satellites and no selected PRNs will result in auto-selection of an SBAS source by the GNSS receivers.