The new block of GPS satellites contain a new acquisition code called M-code. It is an encrypted code from the GPS satellites that allows military receivers to

The new block of GPS satellites contain a new acquisition code called M-code. It is an encrypted code from the GPS satellites that allows military receivers to still be able to perform positioning if the regular coarse acquisition (C/A) code (what we all use) is being jammed. In the current GPS setup there is already an encrypted code (called P-code) but it often requires the GPS receiver first acquiring on the C/A code before being able to track solely on the P code. By contrast, military GPS receivers will be able to lock directly on to the M-code without any coarse acquisition. https://en.wikipedia.org/wiki/GPS_signals#Military_(M-code) https://en.wikipedia.org/wiki/GPS_signals#Military_(M-code) https://www.gpsworld.com/the-promises-of-m-code-and-quantum/ https://www.gpsworld.com/the-promises-of-m-code-and-quantum/