Shortly after posting this question, I found a paper which explained the signal model for GMT very well. I have attached the link to the paper, if anyone ever needs clarification. [End-to-End Moving Target Indication for Airborne Radar Using
Deep Learning
][1]


 [1]: https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=End-to-End%20Moving%20Target%20Indication%20for%20Airborne%20Radar%20Using%20Deep%20Learning&btnG=