The aerostat bit has been very clear to us for a while- the sheer no. of aerostat mounted radars we are busy setting up and low-level detection gap filler radars (meant to be deployed very close to the borders in order to provide some depth in terms of detecting an inbound headed for targets deeper in) is a testament to that. Babur is terrain following last I checked, no?
Specifically though- for example the MF-STAR radar on our to be launched DDGM is quoted to have a detection range in excess of 300Km for high altitude objects, now the range of our ASCM (BrahMos) is 280Km and it does indeed make a climb first before settling into the sea skimming cruise- so when it makes that climb its within the detection range of the MF-STAR, will the said sensor at least detect the launch in this case?
As long as the missile enters the radar cone that extends to the Horizon.
If it stays below that last cone in the horizon it will not be picked up, so depending on that rough idea you can speculate whether it will be picked up or not.