On 11/15/2019 9:58 PM, Its Me wrote:
On Friday, November 15, 2019 at 8:15:33 PM UTC-5, wrote:
On Fri, 15 Nov 2019 18:39:36 -0500,
wrote:
Yet another navigational hazard:
https://www.technologyreview.com/s/614689/ghost-ships-crop-circles-and-soft-gold-a-gps-mystery-in-shanghai/?utm_medium=10today.ad3li.20191115.421.1&utm_sourc e=email&utm_content=article&utm_campaign=10-for-today---4.0-styling
It didn't take a lot of imagination to propose that you could screw
with GPS. It does call into question how well GPS targeting of
missiles will work against a savvy enemy. They might just guide them
all out into the ocean. OTOH the propaganda value might be in blowing
up hospitals and churches.
That's probably not too far behind, but that's not what I read in the article.
What it sounded like in the article is that the AIS systems in the ships were being spoofed to report false locations. If the entire GPS system was being spoofed ALL the locations would be jumping around. It sounded like just some ship's locations were. That would be just the AIS signals.
Since the GPS signal is coming from satellites, scrambling that with ground stations would effect everything in the area, both enemy and friendly devices. That would seem to play havoc on everyone. You can bet that if it's possible to screw with the guidance systems on missiles, they are also designing some smarts into the guidance systems to negate that possibility. Unlike your smart phone, wifi router and PC OS, the military is somewhat ahead of the hacking curve. 
Military equipment (and some commercial airliners) benefit from inertial
navigation systems (INS) that are extremely accurate and are independent
of GPS or ground based navigation sysems (although INS can be used
in combination of other navigation systems under routine conditions).
An inertial navigation system relies only on an accurate known location
at launch or takeoff, are accurate to a few meters over long distances
and cannot be jammed. They do not rely on any external
input or signal. They rely solely on the minute phase shift of a
laser beam split into two opposing optical paths. As a RLG rotates
in one direction or the other, the optical path for the laser lengthens
or shortens (in time) for the laser to complete the path.
The phase shift is detected and computed to determine where the
vehicle (aircraft or missile) is relative to it's launch site. Several
RLG devices, monitoring yaw, pitch, acceleration and deacceleration are
used.
One of my career experiences included a project involved in the optics
and thin film coatings used in the early, high accuracy ring laser gyros
for military use. In time it was determined that for most commercial
applications RLGs made using wound fiber-optics were more than adequate,
although not quite as accurate as an optical mirror type RLG.
Google up "Ring Laser Gyros" and "strap-on" missile navigation systems.