Based on reading (the beginning of) the decision, that appears to be incorrect.
From the first paragraph of the decision: "The warrant authorized installation in the District of Columbia and within 10 days, but agents installed the device on the 11th day and in Maryland. The Government then tracked the vehicle’s movements for 28 days."
And from the footnote on page 2: "1 In this litigation, the Government has conceded noncompliance with the warrant and has argued only that a warrant was not required"
So they got a warrant but messed up and failed to comply with its terms, and to try to preserve the conviction they argued that they didn't have to comply with the warrant.
Edit: Rereading it, andylei's main point is that police just need to get warrants and in order to still be able to use GPS tracking, and that's correct. Apologies for the nitpicking.
From the first paragraph of the decision: "The warrant authorized installation in the District of Columbia and within 10 days, but agents installed the device on the 11th day and in Maryland. The Government then tracked the vehicle’s movements for 28 days."
And from the footnote on page 2: "1 In this litigation, the Government has conceded noncompliance with the warrant and has argued only that a warrant was not required"
So they got a warrant but messed up and failed to comply with its terms, and to try to preserve the conviction they argued that they didn't have to comply with the warrant.
Edit: Rereading it, andylei's main point is that police just need to get warrants and in order to still be able to use GPS tracking, and that's correct. Apologies for the nitpicking.