LINKÖPING, Sweden—Saab unveiled a major upgrade of the JAS 39C/DGripen’s radar here April 27, intended to double its detection and tracking range and give it the ability to track low-radar-cross-section (RCS) targets.
Developed with company funds over the last two years, the Saab PS-05/A Mk. 4 bucks the trend toward electronically scanned arrays in radar design by retaining a mechanically scanned antenna. A prototype made its first flight in a Gripen in December, on a JAS 39D, and the radar is being offered to the Swedish air force and to export customers, with deliveries two years after an order.
Today’s Mk. 3 radar can be converted to a Mk. 4 by replacing two line-replaceable units with new hardware: an all-digital exciter/receiver and a radar processing unit. Part of the performance improvement comes from the exciter/receiver, which Saab claims has such a low noise level that the company found it hard to procure test equipment that would measure it. It also is inherently wideband and can simultaneously receive its own radar signals and emissions from other radars.
The new processor includes a high-capacity, solid-state data recorder and is based on commercial off-the-shelf components. It supports new processing algorithms derived from Saab’s family of Giraffe ground-based radars, including sub-meter-resolution synthetic aperture radar modes and non-cooperative target recognition features. The claimed performance improvement – up to 150 % range increase, or the ability to detect a target with an RCS of 0.1 square meters at the same range at which the Mk. 3 can see a 4-sq.-meter target – points to the use of multi-hypothesis or track-before-detect algorithms to pull targets out of clutter.
Saab decided not to use an active electronically scanned array (AESA) because its cooling requirements would require substantial changes to the Gripen. The company is in talks with the Swedish air force about retrofitting the service’s 100-strong JAS 39C/D force, which will not be fully replaced by the new JAS 39E before 2025. Saab’s perception is that the Swedish air force is viewing upgrades of the C/D more favorably in view of Russia’s regional aggression, and the longer-range radar is a good match for the MBDA Meteor air-to-air missile. A Swedish buy of the Mk. 4 will pave the way for upgrades and new export sales, Saab believes.
The new radar is part of Saab’s strategy to continue selling the C/D version into the mid-2020s, as the first E/F versions will not be available for export beyond Sweden and Brazil until 2022. The final C/D on order was delivered to the Swedish air force in February, but Saab’s flexible production line will be able to meet new orders either with all-new aircraft or (at a lower price) Gripen C/Ds produced by modifying Sweden’s inventory of low-time JAS 39A/Bs.
Slovakia, which has selected the Gripen and still is negotiating a contract, is looking at updated A/B versions. Croatia is expected to select a new fighter in early 2016 and Hungary and the Czech Republic are both looking at exercising options to expand their leased Gripen fleets.