WASHINGTON — A sophisticated airborne radar system developed to track Taliban fighters planting roadside bombs in Afghanistan has found a new use along the U.S. border with Mexico, where it has revealed gaps in security.
Operated from a Predator surveillance drone, the radar system has collected evidence that Border Patrol agents apprehended fewer than half of the foreign migrants and smugglers who had illegally crossed into a 150-square-mile stretch of southern Arizona.
The number of “gotaways,” as the Border Patrol calls those who escape apprehension, is both more precise and higher than official estimates.
According to internal reports, Border Patrol agents used the airborne radar to help find and detain 1,874 people in the Sonora Desert between Oct. 1 and Jan. 17. But the radar system spotted an additional 1,962 people in the same area who evaded arrest and disappeared into the United States.
In contrast, the Government Accountability Office, the investigative arm of Congress, estimated in January that the Border Patrol had caught 64% of those who illegally crossed into the Tucson sector in 2011.
The new tally of unlawful border crossings could complicate White House efforts to pass comprehensive immigration reform after Congress returns from recess next week.
The Obama administration contends America’s borders are more strictly policed than ever, with nearly 365,000 apprehensions last year. Republicans have demanded more guards, drones, fencing and other security measures before legal status is granted to the estimated 11 million people believed to have entered America illegally or overstayed their visas.
President Obama is scheduled to visit Mexico in early May, and efforts to maintain rigorous border security — to stop economic migrants moving north and American-made weapons flowing south — are likely to be among his priorities in discussions with Mexico’s newly elected president, Enrique Peña Nieto.
Michael Friel, a spokesman for U.S. Customs and Border Protection, said the Vader remained in a “preliminary testing phase.” He also said the method used in the agency’s internal reports to compare apprehensions to arrests was flawed because it didn’t include people who were detained after the airborne radar had left the area.
Officials warn that the radar would not work well near border towns and areas where migrants and smugglers can quickly load into a car and blend into highway traffic.
“There is no silver bullet in border technology,” Friel said.
The tests have gone well enough that the agency has asked Congress to allocate money to purchase two more Vader systems. Each system costs about $5 million per year to maintain and operate.