With weather radar, it's not uncommon to see large areas of the image blocked out due to detected range folding. It's my understanding that this occurs when a reflection outside of range comes back after the next pulse has been transmitted, making the receiver think that a late reflection from the first pulse is actually for the second pulse and near by.
It seems to me that it if we could differentiate between pulses, we could eliminate the possibility of range folding error.
My first thought was that each pulse could be sent at different frequencies. They would have to be close enough to not affect the amount of energy reflected, but far apart enough to be easily detected and not assumed to be part of doppler shift. Even something as wide as 1MHz seems to fit this characteristic. Is there a reason we don't use this method today?
If we have to use the same frequency for both pulses, could we instead mount two antennas on the transmitting rig, one polarized clockwise and the other polarized counter-clockwise? In this configuration, the exact same equipment could be used for transmitting with something that just switches between antennas for each pulse.
I'm curious if either method would work, and what the possible pitfalls are.