Surveillance is the observation of public comings and goings of the target who legally doesn't have a right to privacy when in public. The placement of trackers on vehicles is supposed to "aid" the surveillance, not replace the need for manpower to conduct the surveillance. For several years the DOJ was allowing agents to slap trackers on anything they wanted, which then slimed it's way over to DHS. There was a vocal minority that opposed that as being illegal, but they kept doing it until a case finally made it to the SCOTUS. Now trackers require a warrant (as it should be.)
Personally, I think use of this Stingray device will be the same if not more restrictive. Assuming it can only pull location data from the phone it is a lot like a tracker. If it has the capability to pull more than that it should fall under the guidelines for wiretaps. That is a very high bar.
One thing I have seen a lot more these days is the immediate subpoenaing of cell data from a cell company during a man hunt. It is usually used by locals and I don't know whether they have to call a judge each time or if there is a standing policy in place. I was part of a manhunt for a child rapist and it worked well to get us in the ball park. The K-9 did the rest.
They can pull everything from the phone, data, call information, and the call itself.