By REGINA GARCIA CANO, Associated Press

The Baltimore Police Department on Wednesday defended its planned aerial surveillance program, characterizing it as a “remarkable opportunity” for the agency and the city to test a potential crime-fighting tool.

The department's arguments came in a court filing after a grassroots organization and activists sued to stop the pilot program from kicking off. Under the six-month pilot program, cameras attached to up to three airplanes will collect images of the city to help investigate homicides, nonfatal shootings, armed robberies and carjackings.

“As the City suffers persistently high levels of violent crime, philanthropic funding in excess of $3.6 million has made it possible for BPD to evaluate adding a potential investigatory tool for its detectives to use in combatting the most serious of violent crimes," the department's lawyers wrote in their court filing.

The planes, their pilots, analysts and hangar space will be funded by the nonprofit of Texas billionaires Laura and John Arnold. A private company will operate the airplanes and provide staff who will analyze the images.

The aircraft will fly for at least 40 hours a week. The technology is capable of capturing 32 square miles (83 square kilometers) of the city per image per second.

The civil complaint filed in federal court in Baltimore argues the program infringes upon the reasonable expectation of privacy regarding movement, results in indiscriminate searches without a warrant and impedes the right to gather freely.

The police department's attorneys argued that aerial photography and surveillance is not a search. They say the U.S. Supreme Court and the Fourth Circuit Court of Appeals, which has jurisdiction over Maryland, “have held constitutional far more intrusive aerial surveillance than that contemplated” by Baltimore's pilot program.

Baltimore Police Commissioner Michael Harrison had expressed skepticism over the use of the planes, describing the idea as an “untested” crime-fighting strategy, before he announced the pilot program in December.

The Maryland chapter of the American Civil Liberties Union is representing the plaintiffs.