Very interesting article that I came across on Twitter this AM.?ÿ
N10,000, E7,000, Z100.00
PLS - IL, MO, AR, KS, MN, KY
Very interesting.?ÿ?ÿ
By my memory, civilian use of GPS had largely overcome SA through post-processing:
https://gisgeography.com/selective-availability-gps/
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It appears that certain manufacturers are already prepping to combat it:
http://javad.com/jgnss/javad/news/pr20171121.html
?ÿ
Has anyone ever been spoofed while working here in North America??ÿ I have not but am interested in the experience of others.
I don't see that the spoofing has anything to do with Selective Availability, which was a function built into the GPS satellites themselves. A key property of SA was that a long-term average still converged on the right location.?ÿ It was only a jitter.
Spoofing must override the signals from the satellites by broadcasting similar or greater power (which isn't much by the time the satellite signal gets to earth), and modified timing - a long-term shift in the apparent satellite time/distance and velocity.?ÿ But like the guy in the article, I don't see how that gives the arc pattern of false positions they see.?ÿ Modified satellite signals should translate everybody's position generally the same direction, not to the same place.
The Javad page would seem to show a situation where the spoofer signal strength is similar to the desired signal.?ÿ If the spoofer is much stronger, I doubt you get the double peaks illustrated, and must look to consistency in multiple satellite channels to determine if it is valid.
For what it’s worth...I received that article through an geospatial intelligence feed. Perhaps eluding to some new digital warfare being developed by the bad guys in which a “spoof” signal can be delivered, that can be stronger that the true and can guide the good guys off track and into a vulnerable position. Artificial positioning of the sorts...
N10,000, E7,000, Z100.00
PLS - IL, MO, AR, KS, MN, KY
I don't see that the spoofing has anything to do with Selective Availability, which was a function built into the GPS satellites themselves. A key property of SA was that a long-term average still converged on the right location.?ÿ It was only a jitter.
Spoofing must override the signals from the satellites by broadcasting similar or greater power (which isn't much by the time the satellite signal gets to earth), and modified timing - a long-term shift in the apparent satellite time/distance and velocity.?ÿ But like the guy in the article, I don't see how that gives the arc pattern of false positions they see.?ÿ Modified satellite signals should translate everybody's position generally the same direction, not to the same place.
The Javad page would seem to show a situation where the spoofer signal strength is similar to the desired signal.?ÿ If the spoofer is much stronger, I doubt you get the double peaks illustrated, and must look to consistency in multiple satellite channels to determine if it is valid.
Agreed.?ÿ It was more a sentiment as to surveyors learned to deal w/ SA.?ÿ I imagine we will learn to deal w/ spoofing.
Anti-spoofing is the correct term for and reason for the encryption of the P code on L1 and L2
Has anyone ever been spoofed while working here in North America??ÿ I have not but am interested in the experience of others.
For many years we have worked on, or close to, high level military sites. Spoofing or not I do not know, but there are times when GPS is useless. A good example is when modern jet fighters are dog-fighting. Den