The AN/SPN-35 is a computerized automatic landing system installed on the Tarawa-class amphibious assault ship and other LHA/LHD-class warships to give control for aircraft during the final approach and landing.[3][4]
The AN/SPN-35 is used to offer guidance to the aircraft pilot on final approach. It provides relative azimuth, range, and elevation information to the radar operator, who relays this as verbal guidance to the aircraft pilot on approach.[7]
The AN/SPN-35A variant has two antennas: the azimuth antenna (AS-1292/TPN-8) and the elevation antenna (AS-1669/SPN-35). The azimuth antenna is located above the azimuth drive assembly on the stabilized yoke. The elevation antenna is mounted on the elevation drive assembly adjacent to the azimuth antenna.[8]
History
The AN/SPN-35 was developed from the ground-based AN/TPN-8 landing approach control radar.[9](pp171–172)[10] It was first evaluated on the USS Kearsarge in 1962, as an AN/TPN-8 mounted to an AN/SPN-6 stable pedestal and secured to an AN/SPN-8 platform. A prototype was evaluated aboard the USS Bon Homme Richard (CV-31) about a year later as a replacement for the AN/SPN-8 on ASW carriers and small attack carriers.[9](pp171–172) As of 1965, the AN/SPN-35 was being used "primarily on the ASW type carriers."[11]
AN/SPN-35A: Improved stabilization system to compensate for pitch and roll of carrier. Replaces the original mechanical-hydraulic stabilization of the original with an electromechanical stabilization system.[7][9](pp171–172)
AN/SPN-35B:
AN/SPN-35C: Upgrade to AN/SPN-35B. Adds Moving Target Detection (MTD), Track While Scan (TWS), and Built-In Test (BIT) capability.[26]
^Simmons, Larry D.; Ace III, Floyd L. (1995) [October 1995]. Electronics Technician(PDF). Vol. 7. NAVAL EDUCATION AND TRAINING PROFESSIONAL DEVELOPMENT AND TECHNOLOGY CENTER. pp. 2-29–2-30. Retrieved January 12, 2023.
^Thompson, Phil (March 2020). "A4G Pilot Survives Ramp Strike"(PDF). Slipstream. Vol. 31, no. 1. Fleet Air Arm Association of Australia. p. 25. Retrieved January 2, 2023.
^Hobbs, David (2013). British Aircraft Carriers: Design, Development and Service Histories. Barnsley, UK: Seaforth Publishing. p. 295. ISBN978-1-84832-138-0.