Phase modulation on pulse in AESA/PESA radar

[iwantmoresources]

Hello all,
I have been researching radars and their signal characteristics. I stumbled upon the TRM-S search radar, and saw that it uses a phased array antenna as well as using phase modulation on pulse. My question now is: Would the phase modulation not interfere with the beam steering? Assuming it uses a Barker code, it changes between 0 and 180 degrees phase shift, to which the phase shift required for beam steering is added. Would this not result in the beam being steered in an unwanted direction when the part of the signal that is shifted 180 degrees in phase as part of the Barker code passes the phase shifters and is transmitted through the antenna?

 

[T-80U_Valodyana]

The beam pointing is determined by the relative phase difference between all elements on the entire antenna array, not by the absolute phase value of any single element.

Although the 180° phase transition of the Barker code changes the absolute phase at each sampling point within the pulse, at any given sampling moment, all antenna elements apply this transition simultaneously (i.e., all elements either add 0° or 180°). This keeps the phase difference between elements constant, thus the beam pointing remains unchanged.

Your misunderstanding might lie in mistaking the 180° transition required for pulse modulation for the phase step (e.g., 5.625° or 11.25°) used by the phase shifter to control the beam pointing. These are different levels of control within the system, handled by different modules.

 

[iwantmoresources]

The beam pointing is determined by the relative phase difference between all elements on the entire antenna array, not by the absolute phase value of any single element.

Although the 180° phase transition of the Barker code changes the absolute phase at each sampling point within the pulse, at any given sampling moment, all antenna elements apply this transition simultaneously (i.e., all elements either add 0° or 180°). This keeps the phase difference between elements constant, thus the beam pointing remains unchanged.

Your misunderstanding might lie in mistaking the 180° transition required for pulse modulation for the phase step (e.g., 5.625° or 11.25°) used by the phase shifter to control the beam pointing. These are different levels of control within the system, handled by different modules.

Many thanks for your reply.

If I understand correctly, even if the pulse has multiple 180 and 0° shifts as part of the Barker code, those don't matter because they happened before the pulse even got to the antenna?