I am wondering WHY do people think that a stationary target is the most difficult to jam?
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I am wondering WHY do people think that a stationary target is the most difficult to jam?
Well I would think that a "Stationary" gun aimed at a
"Stationary" jammer would be an easy jam for a good jammer.
I just don't see the challenge.
Now a gun panning its beam all over a target, that I would think is a challenge for a jammer.
Or am I nuts....... :?
no idea. I've always wondered myself why anyone in there right mind would care if there jammer was able to jam while stationary. Look at lidatek I heard they pull this crap and look where it got them in there testing. One of the crappiest jammers on the market.
Well, next to the whole angle thing (where it wont jam) I think if they fix that, and drop that REDICULOUS 5 second jamming time- theyd be one of the best.Quote:
One of the crappiest jammers on the market.
back to the topic though, VEiL works better with speed- therefor I would think that speed hinders the laser gun.
Looking foward to the true answer on this one...
Well steve comes down to how a gun obtains a speed reading!
It does it from obtaining distance... so if your moving the distance is always changing and therefore it takes longer for a gun to get a reading...of course you cant tell cause the gun already works fast.
So if you sitting still and your distance is not changing you are a hell of alot eaiser to pick up and obtain a reading of 0 mph ... I woud almost assume that a guns codeing would say something like this.
if distance stays the same
then speed = 0
thats just a psuedo code it doesnt really look like that but it gives you an Idea.
So jamming stationary objects is the hardest thing to do.
A laser gun obtains a speed reading by calculating how much time is between multiple distance readings via infared pulses. - This is the opposite of Vascar whereaes Vascar calculates how much time it takes to travel a set distance. There are times when a laser jammer is jamming and the distance is displayed on the laser gun, but no speed. The ultimate goal of a laser jammer is to prevent a speed reading so you don't get a speeding ticket. You can't get a ticket for a distance reading.Quote:
Originally Posted by Ford_Focus_05
Some jammers do not jam all of the gun's pulses, but jam enough of the gun's pulses to prevent a speed reading. These jammers might take a few pulses to "sync" to the gun's pulses, then send out some jamming pulses, then sync again. This is necessary so that the jamming pulses can be timed to fall fall into the "window" (after the gun sends it's own pulse but before that pulse is reflected back) so that the gun accepts the jamming pulse as it's own reflected pulse.
In these cases, it is possible that a gun might get a distance reading because enough of the pulses make it through. The gun needs less pulse returns to be sure it has a valid distance reading. Althoogh a gun could technically get a distance with only one pulse, it likely uses multiple pulses to be sure the distance reading is valid, BUT probably much less than are necessary for a speed reading as some guns might require 50+ consistent pulses.
With a stationary target, it should be very easy for a jammer to ensure the jamming pulses make it into the window: the "size" of the window never changes, and is always in the same place in relation to the gun's pulses.
But if the target is moving, things become much more difficult for the jammer, as more precise timing is necessary to effectively jam. The window gets smaller and smaller as the target approaches the gun: as the distance between the gun and target gets smaller, the gun's pulses reflect faster. The jammer HAS to get it's jamming pulses into this window or else they are useless. Also, the jammer sees each of the gun's pulses slightly "sooner" as it approaches the gun as well, so it also has to account for that in it's timing. Timing in the jammers generally isn't all that great in the first place, the CPU's aren't fast enough for absolute timing so the jammers use some tricks to pull this off. In my opinion, jamming while moving would be much more difficult for the jammers.
Jim
Damn professor you put that myth to rest
Also take into consideration that since a LIDAR beam is measuring a distance, certain software calculations need to be determined.......
The first few pulses returned and recognized by the LIDAR gun determine if the object is moving......... A 0 speed reading, takes less (for the LIDAR units programming) to produce than a moving one. Less of a process means a faster reading. Its simple like that. Consistant pulse returns? Chuck up a 0 and display the distances calculated....
Stalker and other LIDAR guns which display both distance and speed simulataneously (in some settings) distances are generally displayed first then when all the criteria is met, a speed also appears.......
A jammer which thwarts the speed reading part of the calculation is what the driver is looking for without throwing an error code.
The LIDAR unit is using least squares trying to place data returns along a slanted (sloped) line which the "error correcting software" presumes is a valid range to display data.......
Stalker claims the rejection is above 8 MPH.
However any smooth panning or sweep can simulate a moving LIDAR return that will display ANY speed up to what the gun is designed to display.
If the Stalker does say 10 MPH - 200 MPH, you won't see a 343 MPH reading.
But the Osprey, which has a wider speed display reading window (say 10 MPH - 800 MPH) can produce all kinds of interesting readings.
To get purely a distance reading, ANY LIDAR unit theoretically needs one pulse return to do that...................
Time of flight.
Speed of light is the known constant.
How long did the pulse take to come back?
Oh, hey the objects moving......oh, well we need to do more calculations then.........................
Hmmmmmmmmmmm.
-Suf Daddy