Best defense against Cruise missiles is a very powerful counter electronic/jamming wall across the Russian borders.
Specially closer to Baltic states and Poland. Because long range Cruise missiles depends on GPS guidance those can be easily jammed.. Also it will not be bad for Russia to have decoys of their S-400s and S-500s missiles.
Taking it further, the best defence against cruise missile attack is a widespread dedicated command whose purpose is to monitor russian airspace from ground level to outer space. Together will long range radar... ground, air, and space based, and other sensor assets, it should also have aircraft and ground based defences. That would include large numbers of obsolete systems like SA-3 which is in large numbers available and cheap and certainly capable of bringing down a cruise missile, but also newer more capable systems. Even Osa brought down several cruise missiles in Iraq.
the S model Igla actually had a proximity fuse added to enable it to engage small targets. I have read about a test where 9 Malyutka ATGMs (AT-3 Sagger) were fired to fly at low altitudes as targets for the original Igla missiles. Only 5 were shot down because the remaining 4 missiles did not make contact with the targets because of their small size and because they needed an impact to set off the warheads of the Iglas the 4 that missed just flew past without destroying the missiles.
I would assume that with proximity fuses the Igla-S should have defeated all 9 targets and a cruise missile is not smaller than an AT-3.
I expect Verba would be able to get a lock on at much greater ranges so would be even more effective.
Pantsirs and TORs can also intercept them.. but the counter electronics war have to be there just in case.. this way..
IF US and its Baltic cronies become crazy and launch a surprise full scale attack on Russia by cruise missiles armed with nuclear warheads.. all of them will be jammed and never hit their intended targets.
Actually engaging targets as they entered Russian air space and also targeting the launch sites of those attacking missiles would be the most efficient response.
And EMP walls across Russian borders that can be activated at will ,whenever is need ,will be even better.. it will do wonders.. it will short circuit all the electronics of any low flying missile. This are very doable things that Russia can do right now ..and do not require major investment.. or major research.. as it is the case of creating a new tank or a new combat jet.
EMP walls would also knock out defensive systems too... much better to ensure complete coverage over Russian air space by radar and EO and to remain alert with good communications systems connecting the air defence forces with the other branches of the Russian military.
Counter electronics and EMP stations can also be very effective against drones too.
Sending aircraft in peacetime is still the best option as a pilot can observe the target and make decisions based on what they see. A good targeting pod with magnified optics and data communications means that the target can be filmed and that image data sent to the HQ to decide whether to shoot it down or not.
Most drones when jammed will try to fly back to base and land.
And for detecting low flying drones and cruise missiles on time.. Aerostat with radars on its belly can become very economically effective to scan for 24 hours non stop all Russian Borders.. not even birds will pass undetected. To scan with planes is most costly and can only be done for small period.
Very true... the best solution would be large radar installations, plus many more mobile systems including aerostats... the latter would be especially useful in mountains. Aircraft make sense for intercepting targets or adding extra eyes in places where a better look is needed.
I don't think fitting every tank out for the purpose of air defence makes sense because their primary job is not to sit out in the open emitting enormously powerful radar waves.
Having radar will allow long range detection of enemy vehicles and perhaps using encrypted signals IFF could be included so enemy tanks can be detected at long range and engaged safely.
They wont be worried about any cruise missiles flying over head.