German Air Force tests Hensoldt passive radar system to boost defenses

COLOGNE, Germany — The German Air Force has begun testing so-called passive radar as a complementary surveillance technique for ground-based air defense formations, aimed at helping covert operations surprise adversaries.

Service officials want to find out whether the technology, which measures disturbances in the soup of commercial television and radio broadcast signals permeating crowded airspaces, can provide an “early cue” about approaching threats, German Air Force chief Lt. Gen. Ingo Gerhartz said in an interview with Defense News.

Passive radar works covertly because it measures aerial objects’ echos from existing radio waves and doesn’t itself pulse the airspace for threats. The use of passive radar still requires defenders to turn on their active radar, which exposes them to detection, but only for brief periods.

“Then you only have to go active for the shot itself,” Gerhartz said, referring to active radar guiding an interceptor missile to a target.

The system in question is called Twinvis , made by sensor specialist Hensoldt. Defense News reported in June 2022 that the company was expecting to sell a small number of these systems to the air service, with money from a €100 billion (U.S. $105 billion) special military fund created by the German government after Russia launched a full-scale invasion of Ukraine in February 2022.

A company spokesman confirmed that a system is now under contract.

Passive radar technology has existed for decades, but only recent advances in sensing and signals processing have made it usable in real-world operations, Hensoldt has said.

Experts liken it to a hunter observing an animal move through dense reeds. While the exact type of prey may remain unknown, the position information is crucial for the hunter closing in.

The German Air Force’s expectations around passive radar come in the context of observations from the battlefields of Ukraine, where neither Russia nor Ukraine have been able to establish air superiority because ground-based defenses are so effective.

The term air superiority refers to the ability to deploy aircraft uncontested, which analysts consider a prerequisite for victory.

Germany has delivered several of the latest-generation IRIS-T SLM air defense weapons to Ukraine to help protect population centers from Russian drones and missiles. The system, made by Diehl Defence, is optionally available with Twinvis passive radar.

Sebastian Sprenger is associate editor for Europe at Defense News, reporting on the state of the defense market in the region, and on U.S.-Europe cooperation and multi-national investments in defense and global security. Previously he served as managing editor for Defense News. He is based in Cologne, Germany.

德国科隆——德国空军已开始测试所谓的被动雷达，作为地面防空部队的补充监视技术，旨在帮助秘密行动出其不意地打击对手。

德国空军司令英戈·格哈茨中将在接受《防务新闻》采访时表示，军方官员希望了解这项技术（该技术通过测量充斥拥挤空域的商业电视和广播信号中的干扰来判断威胁的来袭）是否可以提供“早期预警”。

被动雷达之所以能够隐蔽工作，是因为它测量的是空中目标对现有无线电波的回波，而自身并不对空域进行脉冲扫描以探测威胁。使用被动雷达仍然需要防御方开启主动雷达，这会使其暴露于探测之下，但暴露时间很短。

“这样一来，你只需要在发射导弹时启用主动雷达，”格哈茨说道，他指的是主动雷达引导拦截导弹击中目标。

该系统名为 Twinvis，由传感器专家 Hensoldt 公司制造。《防务新闻》在 2022 年 6 月报道称，该公司预计将向德国空军出售少量此类系统，资金来自德国政府在俄罗斯于 2022 年 2 月全面入侵乌克兰后设立的 1000 亿欧元（1050 亿美元）特别军事基金。

公司发言人证实，一套系统目前已签订合同。

亨索尔特表示，被动雷达技术已经存在了几十年，但只有最近在传感和信号处理方面的进步才使其能够在现实世界中发挥作用。

专家将其比作猎人观察动物穿过茂密芦苇丛的动静。虽然猎物的具体种类可能未知，但位置信息对于猎人接近猎物至关重要。

德国空军对被动雷达的期望源于对乌克兰战场的观察，在乌克兰战场上，由于地面防御非常有效，俄罗斯和乌克兰都未能取得空中优势。

“空中优势”一词指的是不受阻碍地部署飞机的能力，分析人士认为这是取得胜利的先决条件。

德国已向乌克兰交付多套最新一代IRIS-T SLM防空系统，以帮助保护人口中心免受俄罗斯无人机和导弹的威胁。该系统由迪尔防务公司制造，可选配Twinvis被动雷达。

塞巴斯蒂安·斯普伦格是《防务新闻》欧洲版副主编，负责报道该地区的防务市场状况，以及美欧在防务和全球安全领域的合作和多国投资。此前，他曾担任《防务新闻》执行主编。他现居德国科隆。