Updates to the Active WAAS SBAS PRNs

Background:

WAAS is a satellite-based augmentation system (SBAS) which provides correction data to standard GNSS receivers capable of tracking SBAS satellites in the North American region.

Issue Summary:

On April 26th, 2022, SBAS PRN 135 began WAAS transmissions, and on May 17th, 2022, SBAS PRN 138 will cease WAAS transmissions.

OEMStar, OEMV, OEM6 and OEM7 receivers are capable of tracking WAAS SBAS satellites (when in view) when enabled.

If the SBAS channels on the receiver are manually assigned (i.e. through the ASSIGN or ASSIGNALL command), the user will need to manually reassign the channels from PRN 138 to PRN 135.

If the SBAS channels are left in the AUTO state (default), the receiver will automatically track the appropriate SBAS PRNs based on the information available in the SBAS almanac.

If the SBASCONTROL command was used to specify that corrections only from PRN 138 be used, the command will need to be reissued for PRN 135 or set to AUTO.

Products Affected: 

• All OEMStar-based products tracking WAAS SBAS satellites.
• All OEMV-based products tracking WAAS SBAS satellites.
• All OEM6-based products tracking WAAS SBAS satellites.
• All OEM7 receivers tracking WAAS SBAS satellites. 

Mitigation:

User intervention is required ONLY if the SBAS channels were manually assigned. The SBAS channels manually assigned to PRN 138 will need to be reassigned manually to PRN 135 using the ASSIGN command.

If the SBASCONTROL command was used to specify that corrections only from PRN 138 be used, the command will need to be reissued for PRN 135 or set to AUTO.

Any questions can be directed to NovAtel support: support.novatel@hexagon.com