Well Agni-II nav system used that ( yours faithfully was amongst the first to point that out) for a BM most INS drift is due to stressful regime after burnout; after that if the INS is re-datumed, then the missile accuracy on INS alone is half as good as GPS. Thus stationary ground based beacons some 100-200 Km off launch pad that are calibrated during peacetime using celestial navigation or GAGAN, will do the job pretty good and then Unkill and Aunti can stuff up their SATNAV signal with no consequence to Chankian Indians.
From a theoretical pov, your gyro drift would be bounded by a constant some degrees per hour.. ofcourse in practical scenarios its impacted by how your platform vibrates etc.
It wont be simple to plonk stationary beacons 100-200km off launch pads, and there are practical issues. If you can track it, so can others, if you can trilaterate, so can others and your beacons become sitting ducks. If you move them, you have logistical issues of calibration being invalidated time and time again due to shocks/temp changes etc. Then you will need to have pre surveyed locations from which to launch your missiles. The crew will have to reach the precise surveyed spot to launch the missile, how would they do that without GPS? You can dig a survey of India stake in the ground, but that gives away your launch location. Either that, or along with the missile crew, you send some BRO guys with survey equipment to look at nearby features like hills etc.
Also, you wont be able to use these signals for cruise missiles and JDAM-kumars which are far more effective bang for buck than ballistic missiles, since they wont fly high enough to get these signals..
Having said that, if DRDO/IA has accomplished these terrestrial pseudo satellites and can assure a highly reliable and available system, hats off to them once again.
If IA or DRDO thinks, they will be allowed to have access to GPS or Glonass over the duration of a hot war with Pakistan, a war that may impinge on the perceived 'vital interests' of the large powers of the world, they are living in a fools paradise.
At another level, this is cheating.. You are fooling yourself and others, you can claim you have reached near zero CEP, but thats only possible if Unkil gives permission. Good luck getting that..
DRDO does what it is asked to deliver. Why blame DRDO blame the services and the military babus who want the same toys as the Frangi. Some one need to tell them base reality that you outline above, with a Muhavara from my village:
- "Shaukeeni Buddhiya,
Chataai Ka Lehanga"
Loosely translated to: Fashion conscious old women of the village, makes Lehanga out of chatai materiel (the materiel that gunnybag / bori is made of) for she cant afford the expensive materiel used to make Lehanga, and does not understand the subtlety of wearing a Lehanga.
You are right and I have a lot of respect for our scientists and soldiers. What I cant understand is the chatterati class not getting the issues at hand and misinforming the public. Hopefully, if public gets why we need a SatNav constellation, (or even much better and cheaper INS) there would be more traction for it.
Thats the reason I am posting this same message over and over again in the hope that someone who understands would be able to get it to the right eyes/ears.
When India has launched its IRNESS then things will be very different. One has to take baby steps before starting to walk and then run.
Ofcourse.. I am not trying to put down IA or DRDO but I want to clear any mis-conceptions in media and public that we have the capability to do precision strikes using GPS/Glonass, when we dont own/have a stake in these constellations. We will be able to do it in tests from Chandipur, but when its really needed from Jallandhar, depends on how friendly we are with the Great powers.
system, the sources said.The missile, designed to operate with both liquid as well as solid fuel, can carry conventional or nuclear pay loads of 500 kg.
but its not going to be easy and have limited impact anyway (only for ballistic missiles). The hard parts (stable oscillators, stable rf, atomic clock, calibration etc), you would already have solved, launching the solution in an orbit will probably be easier if you can do it on the ground. It will also be vulnerable.. There are more than one ways to get the location of the beacons (humint/techint/.. so on).