Leica is always working on software advancements to get the best performance from the latest GNSS signals in order to increase user experience, productivity and compatibility. These improvements are passed onto Leica users as software upgrades for our latest GNSS products and also as updates to manage any major signal changes for legacy equipment.
When GNSS software is not updated for a very long time, equipment may start to experience tracking issues as the satellite messages broadcast differ from those that the Leica GNSS is expecting. We suggest that you keep your equipment under a software agreement, and update software regularly, to get the most out of your asset.
The next big change is coming in April 2019 and GPS messages will be restructured before the system experiences the next end-of-week rollover. You will need to upgrade your GNSS to the latest version (or up to a recommended version) before this time.
Information about the upcoming GPS week rollover 6/7 April 2019
Occurring 6 April 2019, the transmitted GPS week number in the navigation message will rollover from 1023 to 0. All currently operational Leica Geosystems GNSS receivers will not be affected by this rollover.
Nevertheless, to ensure the best possible performance, it is a good practise to use the latest firmware. Please refer to the myWorld portal or contact your local CRK technical support to obtain the latest firmware versions.
1) What is happening?
Occurring 6 April 2019, the transmitted GPS week number in the navigation message will rollover from 1023 to 0. The GNSS receiver must be able to handle this rollover otherwise it could result in an incorrect receiver date of 21/22 August 1999 (1024 weeks back). This wrong date might cause incorrect measurements and observation data.
2) Why is this rollover happening?
The Global Positioning System (GPS) week number rollover occurs in the GPS legacy navigation (LNAV) message every 1024 weeks due to the GPS week number being represented by only 10 bits within the LNAV message. The next GPS week number roll over will occur 18 seconds prior to the 0000Z boundary (Coordinated Universal Time) between 6/7 April 2019.
3) How did Leica Geosystems prepare for the week rollover?
The week rollover has been simulated using a GPS signal generator. Tests have been done with Leica Geosystems GNSS receivers introduced since 2004. This includes the System 1200, GPS900, GS/GR/GM/GG product families. The latest firmware versions were installed in all tested receivers.
Based on the performed tests, we do not expect that the GPS week rollover will cause any issues regarding signal tracking, positioning or observation data logging.
4) Is there a customer actions needed to ensure their operations won’t be disrupted?
No customer action is required, as all currently operational Leica Geosystems GNSS receivers will not be affected by this week rollover.
Nevertheless, to ensure the best possible performance, it is a good practise to use the latest firmware.
Additional information:
Older firmware versions of the tested receivers have not been considered but we expect no difference.
GPS500 has been tested as well and we do not expect any issues. However, in the unlikely case of issues no firmware update will be provided (the phase-out of GPS500 has happened in 2004).
Contact: surveysupportstaff@crkennedy.com.au or your local sales representative.
