German IRIS-T SLM medium-range air defense missile system.

  According to foreign media reports, the Swiss Federal Defense Procurement Office recently announced that it plans to purchase 4 to 5 sets of IRIS-T SLM medium-range air defense missile systems from Germany. At present, the negotiations between the two sides have entered a later stage and the contract is expected to be officially signed in the third quarter of this year.

  In April 2024, the Swiss Air Force launched the bidding for a new air defense missile system. In July of the same year, the IRIS-T SLM medium-range air defense missile system of German Deer Defense Company won the bid. The system was developed from IRIS-T medium and short-range infrared guided air-to-air missiles and is an important part of NATO's "medium-sized extended air defense system".

  It is reported that the Swiss Air Force has recently tested the TRML-4D radar equipped with the system, focusing on the detection capabilities of the radar on PC-12 transport aircraft, F/A-18 fighter jets and helicopters under special geographical conditions.

  Analysts believe that Switzerland's procurement of IRIS-T SLM medium-range air defense missile system is mainly based on the following considerations.

  Promote the iterative upgrade of air defense equipment. The Swiss Air Force's active air defense system is centered on the BL-64 "Hunter" long-range air defense missile and "Sword" short-range air defense missile as the core, and the "Sthorn" portable air defense missile and 35mm dual anti-aircraft gun as the auxiliary. These equipment have been in service for a long time, and their performance shortcomings are highlighted when dealing with modern aerospace threats. With its modular design and multi-target interception capabilities, the IRIS-T SLM medium-range air defense missile system can improve the Swiss Air Force's rapid response and precise strike capabilities to medium and low-altitude targets, and make up for the shortcomings of the existing air defense system.

  Strengthen the detection and early warning capabilities of the entire airspace. As a key part of this procurement, the TRML-4D radar adopts advanced phased array technology, which can track 1,500 targets simultaneously within a 250-kilometer combat radius, and has strong detection capabilities for low-altitude penetration targets. This is extremely important for Switzerland, which is mountainous and has a wide range of high-altitude areas. It can effectively solve the problem of detection blind spots of traditional radars under complex terrain and build a three-dimensional air-infrastructure monitoring network covering the entire area.

  Reduce defense procurement costs. The IRIS-T series missiles are widely installed within NATO, forming a significant scale effect and effectively diluting R&D and production costs. With the help of the multinational joint procurement mechanism, Switzerland can not only obtain price discounts due to bulk procurement, but also rely on the system to integrate technical maintenance and logistics support resources, so as to upgrade air defense capabilities within a limited military budget.

  However, analysts pointed out that the IRIS-T SLM medium-range air defense missile system has many limitations in adapting to Swiss defense needs.

  In terms of equipment performance, the TRML-4D radar detection radius reaches 250 kilometers, while the IRIS-T SLM missile has a range of only 40 kilometers. The performance imbalance results in low radar resource utilization efficiency. Moreover, each system is equipped with only one TRML-4D radar as the core unit. Once the radar is damaged during wartime, the entire system will immediately lose its combat capability.

  In terms of actual combat effectiveness, the system is only equipped with 10 firepower channels, which is at a medium level among similar Western equipment. During actual combat, the number of missiles that the system can guide simultaneously may be further reduced, and compared with other air defense systems with 36 fire channels, it has weaker ability to deal with saturated air strikes.

  In terms of technical characteristics, the IRIS-T SLM medium-range air defense missile system adopts a composite guidance mode of "inertial guidance + GPS and data link correction + infrared imaging guidance". Although theoretically, anti-interference ability and complex terrain adaptability are strong, helicopters in many countries are generally equipped with laser interference systems, which may interfere with infrared imaging guidance accuracy and reduce the success rate of missile interception.

  In addition, due to the large number of orders for the system, there is still uncertainty as to whether the production capacity of Deer Defense meets Switzerland's requirements for delivery time. (Song Zhijian, Liu Haoyang)

[Editor in charge: Wang Jinzhi]