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Unread post10 Aug 2017, 21:35

Post here for factoid about 22 USN JPALS installations in last paragraph - rest of article about CVFs will go in that thread.
Here is the HUFF from NOT THE HUFFington POST: viewtopic.php?f=58&t=15969&p=373438&hilit=huffs#p373438
'No decision' on Raytheon GPS landing system aboard Brit aircraft carriers
22 Jun 2017 Gareth Corfield

"...A rather old webpage [see quote below] from the Federation of American Scientists explains in not-so-complex language how the AN/SPN-41 set works. It’s basically a navalised Instrument Landing System that broadcasts a glideslope along with azimuth information for arriving aircraft. The cockpit display consists of two needles, and once the pilot centres them both, he’s on the right path.

AN/SPN-41 "The Transmitting Set AN/SPN-41A is an electronic landing aid that provides proper flight path data to an approaching aircraft as the aircraft flies into range of ownship radar landing system or into visual contact with ownship optical landing system. The AN/SPN-41A has two separate transmitters (azimuth and elevation) with individual antennas used for sector scanning. The azimuth transmitter is installed on the ship's stern at the centerline of, and slightly below the landing deck runway; while the elevation transmitter is located above the flight deck in the vicinity of the after end of the island to provide the glide slope signal. The AN/SPN-41A uses one-way transmission, ship to air, to a receiver in the aircraft where the angular information is displayed on a cross-pointer indicator. With the vertical needle for azimuth guidance and the horizontal needle for vertical guidance, the aircraft becomes perfectly aligned with the runway centerline, on a standard glide path to the ship's deck, when both needles are precisely centered. Though not technically a radar system, the AN/SPN-41A operates utilizing pulse mode in the Ku-band. AN/SPN-41 and AN-SPN-41A systems are installed aboard CV, CVN, LHA, and LHD class ships. The AN/ARA-63 aircraft approach control system uses the AN/SPN-41 and the AN/TRN-28 transmitting sets. It provides primary or backup instrument approach capability." https://fas.org/man/dod-101/sys/ship/we ... spn-41.htm

JPALS, by contrast, is a GPS-based system. Rather than the ship broadcasting a glideslope to world+dog, JPALS emits an encrypted burst of data that allows the approaching aircraft to precisely fix the ship's position and make a safe landing. The USN is buying 22 JPALS sets for use with its F-35Cs and the USMC’s F-35Bs."

Also from next post down at other URL: "...The USN is buying 22 sets of JPALS to install in both carriers and land bases for training purposes...." [QUE? CVNs & LHAs add up to 22?]

Source: https://www.theregister.co.uk/2017/06/2 ... 2386485241
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/

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