Board Thread:Versus Debates/@comment-30323490-20181122205633/@comment-1751565-20181201135937

Gaara's Automatic Sand Shield does not track chakra when protecting him...for it's automatic protection, they clearly state that it senses danger...most likely similar to how Naruto's Nine Tails evil intent sensory works... So even if something is invisible or undetectable, it will still protect him from danger. Perfect example, Gaara uses his "Sand Sensing" to find and locate Mu, who had no chakra signature nor physical form when using his Water Style Invisibility...and sinc Mu has no chakra signature, I doubt if the Sharingan would even see him.

However Sand Sensing is a War Gaara level ability. Most likely it's just him taking control of His Automatic Sand's danger-sensory perception, and using it in a way other than just for his protection.

With That said, I think the Sand would protect him from a Vanishing Rasengan.