For all those idiots especially from across the border Pakistan who doubted India's MIRV and nuclear weapons capabilities ....
Still used on most if not all contemporary LR/ICBMs including Trident-II D5 and Minuteman-III.
Astro-inertial is one of the most reliable mechanisms for long-range missile guidance.
Do you have this mistaken for a cruise missile
What is the use of MIRV, AAD PAAD when Pakistan can easily sneak in any sub kT device into India via LOC and no one would come to know how when where etc. India needs to be vigil all the time.
Drdo is also using compact variants of similar sensors on some members of RudraM series of air to surface missiles (2 &3)
Incase you didn't know more or less similar systems are used by ISRO in their space based assets
And I believe it will be used in our hypersonic systems too bec they are more or less immune to jamming , highly accurate , resilient to disruptive environment generated around a very high speed vehicle etc
They are laser altimeter.These are obviously optical sensors and you need SAR to reliably map the topography in a way that would make sense to a computer i.e. Digital Elevation Model.
If these sensors are IR-based, they'll be next to useless on an RV which would be heated to such extreme temps during re-entry due to air friction.
If they are visible light-based like TERCOM on cruise missiles, they'll have to wait until they break cloud cover to reliably acquire targets. A missile like Agni-V re enters atmosphere at above Mach 25+ meaning it would hit the ground in about 10 seconds after re-entering atmosphere. Not much time to process or effect any changes to trajectory based on the inputs of these sensors.
Located on the side of the RV, they cannot even see what exactly the RV is heading toward - it would only be seeing the horizon.
The only time where these sensors can potentially see the ground is when the RV is near its apogee and hasn't yet reoriented toward target with the nose down. But from an altitude of several hundred kilometers, these tiny apertures have little hope of discerning individual targets.