A Patriot missile being launched by the Israeli defence forces in the Negev Desert

It appears the drone was destroyed by a missile controlled with an electro-optical sensor

by Stephen Bryen

The drone that came from Syria and entered Israel’s airspace, triggering off a significant confrontation between Syria, Iran and Israel was a knockoff of the United States’ RQ-170. Its distinct silhouette is clearly visible on video of the drone intrusion provided by Israel’s Defense Ministry.

The RQ-170, built by Lockheed Martin, is a stealth drone, meaning that it is specially designed to evade radar. The Syrians, Iranians, Hezbollah and the Russians have been using drones heavily in the civil war in Syria, but they also have been sent into Israeli airspace.

Last July a drone that may have been Iranian or Russian – it has never been positively identified – entered Israel’s airspace. The Israeli launched two Patriot missiles, both of which missed their target. It then tried to shoot down the drone with an air to air missile from an F-15, but that also missed. The drone escaped to Syria.

This could have been the first test of Iran’s RQ-170 clone. If so, it was successful and the drone turned out to be effective, and not just a toy as some experts allege. It also appears to have at least some radar-evading characteristic, enough to fool two Patriot missiles.

Here, in brief, is the background on how the Iranians got the RQ-170. It entered Iranian airspace from Afghanistan on Dec. 4, 2011. It appears to have been diverted by the Iranians, who were able to get control over it and land it at an air base, even though it was damaged.

There are different stories about how this happened, but it seems the Iranians found a significant vulnerability in the command and control system and exploited it. What they got their hands on was, therefore the most sophisticated US drone yet that was built to stealth standards. This means that if properly copied it could evade ground-based and aircraft radars.

The Patriot missile is guided by radar to its target. Air-to-air missiles can be guided by infrared sensors, as used, for example in the US Sidewinder, or by radar, such as the older US Sparrow missiles, and the more advanced AMRAAM.

Because there is very little in the way of a heat signature from an unmanned aerial vehicle or UAV, it is likely the Israeli F-15 fired a radar homing missile. It did not find the target.

Iran produces different types of drones. One of the most common is the Shahed-129. It looks like the US Predator or Reaper UAV and is weaponized, much like the Reaper that carries Hellfire missiles. Russia produces at least two mini-missiles like the Hellfire – the Vikhr and the Ataka-V. The Ataka-V has been exported to Iran.

On June 8 and again on July 20, 2017, the US was able to shoot down two Shahed’s in Syria because they threatened US forces. In an entirely separate incident, a Shahed from Iran entered Pakistan’s airspace near Panjgur and was shot down by a Pakistani JF-17. The JF-17 aircraft was jointly developed by Pakistan and China’s Chengdu Aircraft Industry and its performance roughly matches older F-16s.

Iran’s clone called the Saeqeh, or Thunderbolt, is armed and carried four precision bombs. It is controlled and managed by a command vehicle. Israel also destroyed the command vehicle in a follow up to the Saeqeh shootdown.

There were many who said that Iran was not capable of copying the RQ-170 they captured because they lacked stealth coating and other radar-evading technology. But we know a few things, including the fact that the Iranians shared the RQ-170 exploitation with the Russians, so they had plenty of help in figuring out what they could or could not do.

Iran’s objective was to create a stealthy combat drone, so the Iranian copy is smaller and carries four bombs on the underside. With external bombs, the stealth platform would not be radar evading.

Israel appears to have abandoned using radar-guided weapons to down the Iranian drone. Judging from the IDF supplied video, it almost certainly appears that the drone was destroyed by a missile controlled with an electro-optical sensor, allowing the helicopter pilot to track the drone and kill it. So, the lesson is that electro-optical systems are important in dealing with small platforms and against stealth targets.

This is a lesson that has much bigger implications. As stealth platforms begin to populate the arsenals of potential adversaries, traditional defenses based on modern radars are unlikely to be adequate. Most stealth platforms, such as the US F-22 and the F-35, as well as China’s J-20 and forthcoming J-31, are optimized against radars primarily operating in the X-band.

The X-band is the common radar used for air defense systems. Today there is a shift to a new generation of sensors, exploiting other lower frequency radar bands, such as L, and even UHF and VHF to be able to pick up stealth aircraft. And the newest aircraft are being equipped with advanced electro-optical sensors to be able to track a stealthy adversary.

One presumes the Israelis have not only figured this out but have set up a means of defending against stealth UAVs. But the bigger challenge is defending against stealth fighter aircraft, taking away their advantage.

The US, Japan, Taiwan and others are now challenged by the Chengdu J-20, called the Black Eagle, which has been deployed in the South China Sea. The need for sensors to detect them and shadow them is urgent because the J-20 threatens Japan and Taiwan, as well as the US Fleet operating in the region.