AL Priority - What Have I Been Hit By?

[nano]

I'm not sure the Poliscan is 100pps or the AL would have had no issue with the LR-100. I'm no expert on the poliscan, but I think it's VPR regardless since it's not used in my area I am going to disable it and test this morning against the LR-100 to see if your assumption is correct. It would make sense if the AL was detecting poliscan and sending the wrong jamming signal that we would get IPT. I am confident that AL will have this all worked out tomorrow and I'm glad we were able to help them make the device that much better. I'll let you guys know what I find.

The problem with the pulsrate of 100pps is that there three different laser guns which are using this frequency. First there is the LTI Ultralyte with 100pps, the Jenoptik LaserPatrol and Vitronic PoliscanSpeed.

Since the LaserPatrol is very sensitive to jam codes, it was necessary to set the priority to this gun. A LJ only processes the frequency of the incoming signal, so it is not possible to differentiate, between those guns. Measuring the pulse length is not possible (~10 ns).

The VPS is really a pain in the ass. Detecting is quite difficult, because of the working principle. A laserdiode is sending 15800 pulses per second to a rotating mirror, which splits the pulses to a measurement area of 45°. In theory the incoming signal should be 100 pps, but the reality looks different. The problem is the rotating mirror which isn't rotating with a constant speed. This leads to a "variable" plusrate. The interesting thing is, that for a valid measurement a constant angular velocity system is not necessary, because only the time of flight (from sending the pulse out, to receive it back) is important.
When measuring the laser pulses of the VPS with a high accurate meter you can see that the frequency is jumping on a basis of 100 Hz. Because of this, it is very hard for a LJ to recognize the VPS with a 100% and not falsing to a different signal.
The AL G9 sometimes had problems detecting the VPS, which leads sometimes to a interrupting alarm. In this case, the VPS wasn't recognised correctly and no jamming signal was sent. The much fast processor(s) of the ALP are very helpful in terms of VPS.
Jamming the VPS is another story.