尖端科技軍事雜誌社

  你要怎麼對付速率257公里/時(160英里/時)，距離地面高度122公尺(400英呎)的小型飛行物？怎麼對付能夠從任何地點發射的低空慢速小型飛行物？我們要怎麼對付無法預測飛行路徑且可在任何時刻變換路徑之飛行物？還有，你要如何因應敵方容易獲取而且不停變化的技術？

  隨著無人機越來越普及而且更為精密，這些是全球政府單位、保安機構、以及私人公司時常自問這些問題。在世界各地，從機場和煉油廠到地標性建築物、政府建築物和軍事基地，無人機的威脅是名副其實的飛在頭頂上的問題。依據在紐約的巴德學院(Bard College)無人機研究中心2019年發表的一份報告，全球95％的國家能夠取得並應用這些無人機技術，這引起了美國政府的官員高度關切。

  雷神科技公司(Raytheon Technologies)旗下雷神情報暨太空公司(Raytheon Intelligence & Space)的高能量雷射與反無人空中系統(High Energy Lasers and Counter-Unmanned Aerial Systems)部門主任伊凡亨特(Evan Hunt) 表示：「無人機是空域最具挑戰性的問題之一，它們廉價而且易於在商店購買，隨著先進感測器和打擊能力整合到無人機，它們不只是惹人討厭，還變成了真正的威脅！」

 

雷神對於解決無人機威脅的方案！

  雷神飛彈防禦公司(Raytheon Missiles and Defense)、與雷神情報暨太空公司(Raytheon Intelligence & Space)雷神科技公司兩大事業部門建造的反無人空中系統能夠偵測到來襲的空中威脅、極為精確地辨認它們是什麼，而且使用雷射或者微波(microwave)能量擊落它們。亨特表示：「你必須能夠看見有東西過來，識別它是什麼，而且使用正確的作用器迅速擊落它。反無人空中系統的挑戰在於組成一個能夠在幾秒鐘內協同工作的系統。這些系統依照被稱為反無人空中系統擊殺鏈的步驟工作」。

  美國國防部敲定的術語「反無人空中系統擊殺鏈，counter-UAS kill chain」，就是說以有序的過程，偵測、追蹤、辨認以及擊退威脅。它整合了感測器、指揮與管制還有作用器，在僅僅幾秒鐘之內就擊落無人機。這個協同演出的第一步從監視感測器開始。

1. KuRFS雷達 (KuRFS Radar)

  亨特表示：「我們擁有已經證實防空雷達可以有效的達監視遠處的天空，但我們還增加了一層有效的監視手段，當無人機接近時或者在近距離起飛時，我們使用在無線電頻譜Ku波段運行的感測器，以令人無法置信的精確度來辨認威脅」。

2. 高能量雷射武器系統 (The High Energy Laser Weapon System ，HELWS)

  高能量雷射定向精確，搭配足夠的能源，它們擁有幾乎無限的彈藥供應。這使得雷射成為對付相對廉價無人機蜂群的一種成本效益極佳的解決方案。

3. Phaser™高功率微波系統 (Phaser™ high-power microwave system)

  高功率微波系統也有類似的效用，但是工作方式不同。它們不是對準弱點燒出一個孔洞，而是發出一個脈衝擾亂無人機的控制機制導致它們墜地。高功率微波的效用在於擊落密集隊形之內的多個目標。

  定向能在另一方面的革命性，是不再受制於無人機的不可預測性。即使無人機改變航線，以光速前進的一束能量仍然能夠迅速擊中無人機。亨特說，無人機擊殺鏈的關鍵就是避免僅僅依賴一個系統。不同的無人機威脅——不論單獨一架或者一群，有武裝或者無武裝，大型或者小型，有協調的攻擊機隊或者單獨亂闖——都需要用不同的方式對付它們。

  「沒有一個系統能做全部的事。要想準備好對付我現今面臨的無人機威脅，我們就需要能適應變化、持久有效的系統，它能夠將感測器(雷達)以網路連結識別所偵測到的目標物，然後採用最佳的接戰方式」亨特說。「除此以外，也必須具備多層防禦——在遠距外層，現有已驗證完成之防空系統可以接戰危害性較高的軍事化威脅，而在近層，則需要極為精準的感測器及非動態能量之武器來接戰」。

  對付越來越多的無人空中系統威脅顯然是精密且複雜的事情，需要動用不同類型的專用系統參與，而且在幾分鐘內完成它們的工作。隨著無人機威脅以及對抗它們的技術在未來的歲月中演進，保護免於它們威脅的防禦手段也會同步演進。

 

Downing a drone: Systems work together to fend off attacks

How do you deal with something small that moves 160 mph, 400 feet above the ground? Something small that flies low, slow, and could be launched from anywhere?   How do we defeat something with an unpredictable flight path that could take a sudden turn at any moment? And how do you plan for adversarial technology that’s readily available and constantly changing?

Global governments, security agencies, and private companies frequently ask themselves these questions, as drones become more prevalent and sophisticated. From airports and oil refineries to landmarks, government buildings and military bases around the world, drone threats are a problem that is literally flying right above our heads.

According to a 2019 study published by the Center for the Study of the Drone at Bard College in New York, more than 95 countries have access to such drone technology, and that has government officials concerned.

Raytheon  Solution

“Drones are one of the most challenging issues in airspace; they’re cheap and easy to get from a store,” said Evan Hunt, director of High Energy Lasers and Counter-Unmanned Aerial Systems at Raytheon Intelligence & Space, a Raytheon Technologies business. “With advanced sensors and strike capabilities integrated into them, they become not just a nuisance, but a real threat.”

Raytheon Missiles and Defense, and its sister business unit, Raytheon Intelligence and Space, build modern counter-UAS systems that can detect incoming airborne threats, discern what they are with extreme precision, and use lasers and microwave energy to bring them down.

“You have to be able to see that something is coming, identify what it is and quickly take it down with the right effector. The challenge of counter-UAS is pulling together a system that works in concert in mere seconds. These systems follow the steps of what is called the counter-UAS kill-chain,” said Hunt.

The counter-UAS kill chain, a term coined by the U.S. Defense Department, is the sequential process to detect, track, identify and defeat threats. It combines sensors, command and control and effectors to take down drones in mere seconds. The first step of this coordinated dance starts with the look-out sensors.

1. KuRFS Radar

“We have proven air defense radars that watch the skies at far distances, but we’ve also added a new layer of sight.,” Hunt said. “As drones close in or are launched at short range, we use sensors that operate on the Ku-Band of the radio frequency spectrum to identify threats with incredible precision.”

The company’s counter-UAS KuRFS radar, deployed after only 19 months of development, detects an approaching drone swarm and then singles out individual drones. Next, system operators can point directed energy, like a laser, at each drone and burn them down.

2.  The High Energy Laser Weapon System (HELWS)

High-energy lasers are precise, and with an adequate power source, they have a virtually unlimited supply of ammunition. This makes lasers a cost-effective solution to deal with swarms of relatively inexpensive drones.

3.  Phaser™ high-power microwave system

High-power microwave systems are similarly effective, but work differently. Rather than pinpoint a weak spot and burn a hole, they send out a pulse that disrupts drones’ control mechanisms and brings them crashing to the ground. They’re effective at downing multiple targets in close formation.

Another way directed energy is revolutionary is it negates the unpredictable flight paths of drones. An energy beam that travels at the speed of light can reach a drone fast, even if it changes course.

The key to the drone kill-chain, according to Hunt, is to avoid relying on just one system. Different drone threats—whether a single drone or a swarm, armed or unarmed, big or small, part of a coordinated attack or a curious pilot—require different approaches to counter them.

“There is not one system that can do it all. To be ready for drone threats facing us today, we need adaptable, enduring systems that can deploy networked eyes with a variety of ways to engage what sensors are seeing,” Hunt said. “Beyond this, there needs to be layers of defense—proven air defense systems designed to engage the more menacing militarized threats at the outer layers into the layers that require extremely precise sensors and non-kinetic effects.”

Dealing with the ever-growing number of autonomous, flying threats may look like sophisticated, with different types of specialized systems stepping in and, in a manner of minutes, doing their part. As drone threats and technologies to counter them evolve in the coming years, so will the defenses that protect against them.