3 ms·
The full 37500 bits data is set is called “GPS Navigation Message”, or at least that’s what the ESA website call it. (https://gssc.esa.int/navipedia/index.php/
by tverbeure 2y ago
The full 37500 bits data is set is called “GPS Navigation Message”, or at least that’s what the ESA website call it. (https://gssc.esa.int/navipedia/index.php/GPS_Navigation_Message https://gssc.esa.int/navipedia/index.php/GPS_Navigation_Mess...)
And, yes, I understand that time message gets sent at a much higher rate, hence the “it’s not that simple” part.
But I still have a hard time to believe that it would have been impossible to find 2 or 3 bits in the overall message to include the MSBs for the weeks. GPS units with built-in support for WNRO (due to permanent storage) would be able to ignore it, other units would be able to correct the epoch after 12 minutes (or a multiple in case of data corruption.)
- akira2501 2y agoIt would have been possible but it would have required a trade off against the other data in the message; however, the goal of GPS is to provide accurate position data, not to provide convenient "calendar time" to individuals. Which is why they spent so lavishly on high precision correction parameters and so sparsely on low precision time of calendar parameters.
- tverbeure 2y agoFrom the start, GPS has been used for accurate time keeping as well. And for later versions of the GPS protocol the week number was increased to 13 bits. https://www.gps.gov/systems/gps/modernization/cnav/ https://www.gps.gov/systems/gps/modernization/cnav/
- deleted 2y ago[deleted]