[duelingjello]

EDIT: I read some other, more complete sources, it looks like jamming.

Disclaimer: I worked at Trimble Nav Ltd. in the radio group.

In general, GPS errors could also be caused by:

- PRC MIL jamming non-military non-BeiDou positioning systems to prevent drone or cruise missile attacks

- US MIL increasing Selective Availability (SA) on or disabling the unencrypted signal for a region

- Physical obstructions: trees, buildings, etc.

You'd think huge ships would have laser ring gyro INS and GLONASS/Galileo/BeiDou as a backup? Depending on a locally-jammable, unencrypted data monoculture (GPS) for multiple critical systems is a SPOF and insane.

[khuey]

Selective Availability is on its way out. In addition to being disabled for 20 years, supposedly the new 3rd generation GPS satellites were built without the capability.

[XorNot]

Also most of the US GPS guided ordnance cannot function when selective availability is enabled.

The reality is that cheap GPS chips enable so much more capability then the risk of your enemy benefiting from a mapping system.

[Animats]

JDAMs apparently have had an inertial system for backup for some time. MEMS gyros are good enough to guide from release to target. DARPA has quietly been working on compact, low-cost guidance without GPS for a while.[1] Doesn't seem to have filtered down to the commercial market yet, and that's probably not an accident.

[1] https://www.darpa.mil/program/micro-technology-for-positioni...

[nradov]

Considering that BeiDou uses the same frequency range as Galileo, is it really feasible for the military to jam one without the other?

[leppr]

> EDIT: I read some other, more complete sources, it looks like jamming.

Care to share those? It's an interesting topic but I don't have the base knowledge to make out bogus/incomplete information.