South Korea’s Defense Ministry said Monday it is considering upgrading the software of the Patriot Advanced Capability (PAC)-2 system to improve its accurasy so as to better cope with North Korean missile and nuclear threats.

PAC-2s have been deployed to counter increasing threats from the North’s low-flying, short and medium-range missiles, as part of Seoul’s plan to build an independent theater missile defense shield, dubbed the Korean Air and Missile Defense (KAMD) network system.

But calls for upgrading the system have arisen after a recent study showed the PAC-2 system’s interception success rate remains below 40 percent. Defense Minister Kim Kwan-jin also said last week that South Korea is considering upgrading the system to the more accurate PAC-3 system.

The remark, however, raised suspicions Seoul may join the U.S. missile defense system.

On Monday, Maj. Gen. Shin Won-sik, who is in charge of the ministry’s policy, said the government is currently looking into the PAC-2 system’s capability to decide whether to adopt the software system for the PAC-3 missiles, which would allow it to receive intelligence collected by the U.S. satellites.

“It would take time to remove PAC-2 missiles to replace them with PAC-3 missiles with trillions of money,” Shin said in a briefing. “We will consider upgrading the software system of the

PAC-2 system operating in radar and ballistic missile command bases to a PAC-3 system.”

South Korea has bought 48 PAC-2 systems, including launchers, from Germany at a cost of 1 trillion won (US$909 million), but the PAC-2 launchers can’t be used for the PAC-3 system.

The PAC-3, a “hit-to-kill” interceptor capable of striking an incoming missile at altitudes of up to 30 km, supposedly causes no damage on the ground since it destroys the payload high up in the air.

Shin said the state-run Korean Institute for Defense Analysis and the Missile Defense Agency and the U.S. Department of Defense have been jointly conducting a study on the defense system to figure out how to integrate the missile systems between the two nations, taking into consideration the military command system, placement of missile batteries, topography and climate.

“We are jointly conducting simulations to assess on what scale one Patriot missile can be effective when demanded by the military,” Shin said. “The results of the S. Korea-U.S. joint study will be released by the end of this year.”

Shin stressed that the most important part of establishing the KAMD relies on intelligence information collected by the U.S. satellites, because South Korea does not possess its own satellite system to detect North Korea’s ballistic missiles.

“The first mission of the KAMD is what kind of information it acquires from (U.S.) satellites and how it shares that information,” Shin said. “The second task lies in how the South Korean military’s five ballistic missile radars can use U.S. military’s radar information acquired from sea-based facilities in times of war.”

U.S. Defense Secretary Leon Panetta said in last week’s Pentagon briefing that Washington is still in consultations with Seoul over its future role in a regional missile defense system, raising speculations Seoul could take part in the U.S. missile defense system.

The South Korean military plans to deploy two Israeli ground-based missile-defense radars, named “Green Pine,” later this year to detect North Korea’s ballistic missiles, according to ministry officials. (Yonhap News)