HR-44

THe HR-44 is a short-range multi-purpose I-band radar developed in Menghe in the 1990s. It has a maximum instrumented range of 20 to 40 kilometers, though its practical range is limited by the radar horizon; therefore, the antenna is usually mounted high on a ship's mast. Early versions are only capable of surface search and low-altitude air search, though later variants can also be used for fire control and beacon tracking. All variants lack IFF interrogator antennas, meaning that ships carrying this system must be fitted with a separate IFF interrogator array.

Development

Work on the HR-44 began in the mid-1990s, after Dayashina refused to export the AN/SPQ-9 radar to Menghe. It was originally intended to be installed on light surface vessels, such as the Mugunghwa-class corvettes and Plan 215 corvettes, as part of their refits. Initial design work focused on search and tracking capability, while leaving the option of adding fire-control capability in later variants.

Description

The HR-44 consists of a rotating antenna inside of a cylindrical radome which measures approximately 3.2 meters in diameter by 3 meters in height. It is usually mounted high up on a ship's superstructure in order to increase the distance to the radar horizon, as the radar's high frequency limits atmospheric ducting and surface-wave propagation. The antenna inside the radome rotates at a speed of 30 revolutions per minute, scanning each bearing once every 2 seconds.

The antenna emits radar waves in the I-band when active, producing high-resolution returns from targets with a small radar cross-section. This frequency was originally chosen to allow the detection of submarine periscopes and antennas. It also increases the range at which anti-ship missiles can be detected and the accuracy with which they can be tracked.

In all variants, the HR-44 only scans for targets on or near the surface. Menghean sources claim that it can detect airborne targets up to an altitude of 200 meters at a range of 10 kilometers, increasing to 800 meters at a range of 40 kilometers. This means that in addition to surface contacts, it can also detect low-flying aircraft and sea skimming anti-ship missiles. In track-while-scan mode, it can use the Doppler effect to determine the target's speed and distinguish moving objects from background clutter. It cannot, however, detect high-flying aircraft, and it lacks built-in height finding capability.

On variants N onward, the HR-44 also has a "focused targeting" mode in which the antenna stops at a fixed azimuth and tracks a single target. This generates higher-resolution range, speed, and bearing data, without the 2-second delay between full rotations, useful for generating a firing solution on a small, fast, maneuvering target. This mode also allows the user to detect falling shells and splashes near the target and correct gunfire accordingly. In focused targeting mode, however, the radar does not scan outside the selected bearing, which can leave the ship exposed to other threats if another radar set is not active.

Variants

HR-44G

Initial version, introduced in 1998, with search-and-track capability but no gun fire control option. Maximum range of 20 kilometers.

HR-44N:

Software upgrade which adds gun fire-control capability. The antenna is identical to that on the HR-44G. The system can generate firing solutions in both search-and-track mode and focused targeting mode, though in the latter mode targeting is more accurate and continuous fire correction is possible.

HR-44D

The HR-44D is a comprehensive upgrade introduced in the late 2000s. It features an all-new antenna with increased range (40 kilometers) and resolution. The new antenna can also detect air targets at a bearing of up to 30 degrees above the horizontal, or 11,500 meters at a range of 20 kilometers. It is also 3D capable, generating altitude information for radar contacts. Rotation speed with this model is increased to 60 rpm, halving the interval between tracking updates. The radome covering the antenna appears to be nearly identical in its external dimensions, but with a rounded top.

HR-44R

The HR-44R consists of the HR-44D antenna mounted on a taller cylindrical pedestal. This pedestal incorporates an infrared camera on a track that runs around the base of the radome. In search mode, it scans the horizon in real time at the same rotational speed as the radar antenna, to generate more precise bearing information, classify targets by their appearance, and detect stealthy ships or missiles by their infrared signature. The camera can independently stop its rotation and track a single target while the radar continues rotating, or it can rotate at a reduced speed for greater resolution with reduced time between updates.

Ships using the radar

• Mugunghwa-class corvette (Chijahwa type refit, 1998-)
• Mirun-class corvette
• Yechŏn-class frigate

Specifications

• Height (radome): 2.3 meters
• Diameter (radome): 2.1 meters
• Weight: 700 kg
• Maximum detection range:
  • HR-44G,N: 20 km
  • HR-44D,R: 40 km
• Rotational speed: 30 rpm
• Frequency range, active: I band
• Number of targets processed:
  • HR-44G,N: Up to 50
  • HR-44D,R: Up to 200