Patria's passive radar effectively fills gaps in air surveillance

The passive radar is invisible to the enemy

Patria MUSCL can provide 360-degree surveillance up to hundreds of kilometers away, making it well-suited for air surveillance and border control. Surveillance can also be focused on a specific target to protect critical infrastructure. 

– The main advantage of the passive radar system is that it does not produce any signal trace itself. Thus, Patria MUSCL is practically invisible to enemy signal intelligence, says Aaro Malila, Product Manager at Patria. 

The signals sent by traditional radars immediately reveal their operation and location to the enemy's electronic surveillance sensors. In the worst case, it can take only a few seconds to locate, after which the enemy can target the radar with electronic jamming or direct fire.

Advanced signal processing detects targets

Patria MUSCL utilizes existing radio signals in the environment for its measurements. Typically, these are broadcast signals from radio or television stations. By using these, the radar can calculate the location and movement of an airborne target by comparing the signals reflected from the target with those that have traveled directly. 

The system can simultaneously track over a hundred targets.
– Due to its operating principle and low frequencies, Patria MUSCL has better capabilities to detect stealth targets compared to traditional radar, Malila notes. 

The shapes and surfaces of stealth aircraft are designed to scatter the signals of traditional surveillance radars so that they do not return to the radar receiver. In the case of Patria MUSCL, since the radar receivers are located in different places than the transmitters, scattering the reflections away from the transmitter does not provide as much benefit.
– The ability to detect stealth aircraft is improved by the fact that Patria MUSCL also utilizes signals with lower frequencies than traditional radars, Malila explains.

The result of Patria's long-term development work

Patria MUSCL system's station equipment, such as antennas and processing units, can be transported to the desired location, for example, by an off-road vehicle, or they can be mounted on a trailer pulled by a vehicle or on a ship. The antennas can be mounted on various masts as needed, such as a portable telescopic mast or a movable trailer mast. Since the system is designed to be used unmanned and remotely, some of the system's functions and components can be located far from the actual radar stations. 

Patria MUSCL produces standardized air surveillance data that can be transferred through interfaces for use in various command systems. In addition to the real-time situational picture, the data can be stored and analyzed later. 

The passive radar is a relatively old invention in terms of its operating principle, but Patria's product development has refined it into an efficient radar system. Kalle Martikainen says that Patria has been developing passive radar system technologies since 2010. 

The results of the development work are utilized in a product family focused on intelligence and surveillance.
– Like many other products, Patria MUSCL was also born through many stages and determined product development, Martikainen says. 

He explains that Patria MUSCL hardware is durable and designed for demanding military use. The modular system utilizes commercial technology, allowing the system to be flexibly updated as technology advances. 

– Thanks to its modularity, Patria MUSCL can be smoothly customized to meet the customer's needs and requirements, Martikainen says. 

The advantages of Patria MUSCL also include easy portability and quick deployment. The equipment can be installed at a fixed location, but it can also be transported by vehicle or carried to the desired location and quickly put into operation. 

– Various variants of Patria MUSCL can be developed. The system can also be integrated with Patria's ESM surveillance capability, which is based on signals emitted by the target itself, Martikainen notes.

Patria MUSCL effectively covers blind spots

Aaro Malila says that the main purpose of a system like Patria MUSCL is to complement air surveillance coverage. Due to their vulnerability, active radars must be kept in the background in a war situation, while their operating periods can be very short, but the passive radar system can be placed closer to the opponent. 

– A passive radar does not fully replace traditional radars, but it provides a valuable addition to air surveillance needs, Malila reminds..