Hello:
In MESG, we can model pulses, MOP, and antenna patterns and so on. Can we model Doppler shift on the signal /pulses? If so how can we do that? If you could give an example that would be greatly appreciated.
Thanks
Regards
Janaka
Hello:
In MESG, we can model pulses, MOP, and antenna patterns and so on. Can we model Doppler shift on the signal /pulses? If so how can we do that? If you could give an example that would be greatly appreciated.
Thanks
Regards
Janaka
Hi Janaka,
You will want to enable Kinematics at the Simulation Level.
Then add Way Points at the Platform level.
MESG will calculate Doppler based on the Way Points
Check out the "Santa Cruz Island GPS.mesg" example.
It can be found in MESG under the file open menu in "Open Simulation Example".
Hope this helps
Pete
Thanks so much Pete.
For this, I need at least two UXGs, am I right? One for TX and another for RX? The "Santa Cruz Island GPS.mesg" example also has 4 UXGs.
At the moment I have one UXG. So I wouldn't be able to see the simulation, would I?
Thanks
Janaka
Hi Janaka,
The Kinematics accounts for all relative motion between Emitter platforms and the SUT platform.
You only need a single UXG to play PDWs. The Doppler affect is added to the PDWs.
The example you looked at had 4 UXGs to insure the desired pulse density. You can delete 3 of the UXGs in that simulation and you will see more dropped pulses. When there is insufficient hardware You can change the emitter priority or the emitter position in list of emitters to alter which pulses are dropped.
Another possibility is to disable the download on three of the instruments and assign the address of your UXG to the remaining instrument. This way the pulse density doesn't change but your UXG will only generate a portion of it. You can move your UXG to each of the other 3 instruments and see the different portion of the overall scenario.
If you are trying to do AoA you will need at least one UXG per port on the SUT.
Pete
Thanks so much Pete.
With respect to AOA, I am trying to understand the scenario in such a case. There is an example in MESG with 2 UXGs. What is a actual reason of having two UXGs? Is it just to minimise the dropping pulses or as you mentioned before, one to act as platform and the other as SUT? What are the roles of the primary and secondary? I see SUT has two antennas.
In case if we have 4 UXGs, how the primary and secondary behave? Primary as the SUT and secondary as platforms?
Greatly appreciate your reply!
Have a great day
Janaka
Hi Janaka,
I hope I never indicated that you need a UXG for the platform, and another for the SUT.
In MESG the SUT does not transmit any signals, it is strictly a receiver.
The number of UXGs required for a given scenario is dependent on the number of ports on the SUT (assuming AOA between ports is desired) and the number of simultaneous or overlapping pulses you would like to generate.
If your SUT has 4 ports and you only need a maximum of a single pulse at a time (no overlapping pulses) you will need 4 UXGs. This can be composed of either 4 N5193As or 4 N5194As with one N5193A as the LO.
Think of either of these two configurations as a channel.
If you need 2 pulses simultaneously/overlapping you will need 2 channels or twice as much hardware.
(2) 4-N5193A or (2) (4-N5194A 1-N5193A as LO)
Notice that the amount of hardware can be independent on the number of emitters you want to generate.
Typically the more emitters the higher the overall pulse density and simultaneous/overlapping pulses. MESG will drop simultaneous/overlapping pulses based on the number of channels in the Test System. Emitters can be given a priority (lower numbers being higher priority) for when overlaps occur. Lower priority pulses will be dropped before higher priority pulses.
As I mentioned before all of the relative motion between platforms and the SUT are encoded into the PDWs. This includes platform antenna radiation patterns and scan patterns as well as the SUT antenna radiation pattern and scan pattern. So you only need a single UXG per port on the SUT. If you SUT has a single port you only need a single UXG. You may need more UXGs if the dropped pulse ratio is too high for a given scenario.
Hope this helps.
Pete
Hi Janaka,
The Kinematics accounts for all relative motion between Emitter platforms and the SUT platform.
You only need a single UXG to play PDWs. The Doppler affect is added to the PDWs.
The example you looked at had 4 UXGs to insure the desired pulse density. You can delete 3 of the UXGs in that simulation and you will see more dropped pulses. When there is insufficient hardware You can change the emitter priority or the emitter position in list of emitters to alter which pulses are dropped.
Another possibility is to disable the download on three of the instruments and assign the address of your UXG to the remaining instrument. This way the pulse density doesn't change but your UXG will only generate a portion of it. You can move your UXG to each of the other 3 instruments and see the different portion of the overall scenario.
If you are trying to do AoA you will need at least one UXG per port on the SUT.
Pete