The basis for the current litigation Schmidt v. City of Norfolk[0] is the 2018 Supreme Court decision Carpenter v. United States.[1]

The ruling in Carpenter is essentially that you can't have prolonged surveillance without a warrant.

[1] https://www.supremecourt.gov/opinions/17pdf/16-402_h315.pdf

[0] https://www.courtlistener.com/docket/69288422/schmidt-v-city...