Why Iranian Missiles Can Hit Targets in Israel Despite GPS Jamming

No missiles built in Iran over the past 12 years use international positioning systems, including Global Positioning System (GPS), the Fars agency has reported, citing a source in the Iranian Islamic Revolutionary Guard Corps (IRGC).

The Israeli military has intensified scrambling GPS signals across the country while bracing for possible retaliation from Iran or Shiite militias over the assassination of senior Iranian generals in the Syrian capital of Damascus.

For their part, the Iranians signaled that Israel's efforts to jam GPS are in vain, since no missiles built by the Islamic Republic over the past decade use international positioning systems.

The Iranian comment is by no means an exaggeration, according to Konstantin Sivkov, a member of the Russian Academy of Rocket and Artillery Sciences and doctor of military sciences. He drew attention to the fact that the first US-made Tomahawk missiles carried out precision strikes before the Global Positioning System (GPS) became operational.

"There is a [navigation] system which is called 'Tercom' [terrain contour matching] by the Americans," Sivkov told Sputnik. "How does it work? The missile flies using its onboard control systems. When approaching a certain correction site, this rocket turns on its radio altimeter (RALT). It skirts terrain using the radio altimeter, which allows it to take pictures of the terrain at a certain height, after which the Tomahawk on-board control system correlates the terrain that it took a picture of with the terrain that is included in this missile and determines the location of the missile with an accuracy of meters."

"After that the missile makes a maneuver to set its course to the designated target and flies further to the next correction site. There are about two or three such correction sites that ensure the movement of this missile with very high accuracy into the target area. In the target area, the missile goes slightly up and then, with the help of a radar station or with the help of optoelectronics, takes a radar portrait of the area, after which it compares it with the picture of the area, which is recorded inside, identifies the object that must be hit with very high accuracy and hits it. The accuracy of the strike in this case has a circular error probability of 5-10 meters."

When GPS became operational in the 1990s, the US military utilized it to correct the rocket's trajectory in the event of urgent changes to the task, aim and location, continued Sivkov. The GPS allows controllers to make corrections to the missile's mission, whereas the Tercom system uses initially uploaded data, according to the expert.

"However, the Tercom system still exists and Iran uses it. We use such a system too. This is quite feasible. And the Americans have such missiles. For instance, the Tomahawk has two flight control systems - GPS and Tercom," Sivkov explained.

Iranian-made missiles using Tercom could hit the mark easily, according to the expert. "The accuracy of Iranian missiles launched in response to the assassination of Gen. Qassem Soleimani was 10-15 meters in terms of circular error probability. This is an excellent result for medium-range ballistic missiles. This is a result equivalent to our Iskanders," Sivkov said, referring to Tehran's Operation Martyr Soleimani of January 8, 2020.

While avenging Soleimani's death, the Iranian military fired over 12 ballistic missiles at the al-Asad Airbase in Al Anbar Governorate, western Iraq, as well as another airbase in Erbil, housing American military personnel. As per the US press, no American troops were killed during the attack. Soleimani was assassinated in a US drone strike while he traveled from Baghdad's international airport on January 3, 2020.

Iran's return attack was largely symbolic, with then-Iranian Foreign Minister Mohammed Javad Zarif saying that Tehran did not "seek escalation or war, but will defend ourselves against any aggression."

US Soldiers stand amid damage at a site of an Iranian bombing at Ain al-Asad Air Base, in Anbar, Iraq, Monday, 13 January 2020. Ain al-Asad Air Base was struck by a barrage of Iranian missiles on Wednesday, in retaliation for the US drone strike that killed a top Iranian commander, General Qassem Soleimani, whose killing raised fears of a wider war in the Middle East.

© AP Photo / Qassim Abdul-Zahra

On April 1, an air strike on the Iranian Embassy in Damascus killed 12 people, including General Mohammad Reza Zahedi, a commander of the Quds Force, his deputy General Mohammad Hadi Hajriahimi and five other officers.

Despite Israel not officially taking responsibility for the attack, Israeli military officials remarks leave little if any doubt about Tel Aviv's complicity. Thus, Tel Aviv military spokesperson Rear Admiral Daniel Hagari rushed to claim to CNN in the wake of the strike that the Iranian embassy buildings were in fact military facilities. Iran’s President Ebrahim Raisi stated on April 3 that the attack "will not remain unanswered."