Doppler shift due to observer speed will almost always (i.e. for anything other than an actual ballistic missile, and even then only a missile traveling west) be less than the doppler shift due to satellite speed for a stationary observer. So, artificially restricting the doppler spread isn't an effective method of implementing the COCOM restrictions. It would also make PLL lock-up more difficult.
Concorde is old enough that its operators probably never went to the trouble of doing the paperwork to have a GPS integrated with the rest of the NAV system. For its (relatively) short flights, an internal navigation system plus VHF or LF radionav works adequately (and there were very few, if any, GPS/WAAS approaches certified by the time of its retirement).
Concorde is old enough that its operators probably never went to the trouble of doing the paperwork to have a GPS integrated with the rest of the NAV system. For its (relatively) short flights, an internal navigation system plus VHF or LF radionav works adequately (and there were very few, if any, GPS/WAAS approaches certified by the time of its retirement).