Paddles Monthly Dec 2012
http://www.hrana.org/documents/PaddlesM ... er2012.pdf (1.4Mb)
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Joint Precision Approach and Landing System (JPALS)
[author] - Ken “Waldo” Wallace is a former Tomcat pilot and currently the JSF and JPALS liaison for Navy PMA-213 at Coherent Technical Services
As of this writing, a JPALS engineering unit is being installed onboard the USS George H.W. Bush (CVN-77) for at-sea test and evaluation with an F/A-18, MH-60, and King Air test aircraft in early 2013. This takes the next step beyond the LSO OAG presentations, Fleet Project Team forums, and technology demonstrations, and gives Paddles the opportunity to view the next generation precision approach and landing system at work in the operational environment.
Designed to replace aging sea-based and land-based aircraft landing systems, JPALS is a GPS-based system to provide enhanced joint operational capability in a full spectrum of environments ranging from CAVU to Sea State 5 in all weathers in a hostile environment. By complying with the International Civil Aviation Organization (ICAO) for Ground Based Augmentation System (GBAS) and Space Based Augmentation Systems (SBAS), JPALS provides an interoperable civil divert capability. JPALS incorporates both encrypted data link and GPS anti-jam technology with high levels of accuracy, reliability and capabilities beyond what we have today.
NAVAIR is developing JPALS with an incremental strategy to meet all requirements from replacing the SPN-46, SPN-35, and PAR for manned aircraft to landing unmanned aircraft both ashore and at sea. The first step of which is to achieve 200 ft. decision height with ½ NM visibility at CVN and L-Class ships.
System Overview
Figure 1 (on page 2) depicts the Operational Concept of the nodes and information exchange for JPALS Increment 1. The JPALS data link provides shipboard information for the aircraft to determine a Relative Navigation (RelNav) location to the ship.
The development schedule calls for two separate data links for JPALS. For Increment 1, the JPALS UHF data link is for the air wing aircraft (F/A-18 E/F, EA-18G, E-2D, C-2A, MH-60R/S and other future platforms) with a line of sight limit of 200 NM (for RelNav). Within 60 NM, the aircraft logs into the network and initiates two-way data link for aircraft parameters to be sent to the ship for surveillance and air traffic control. Within 10 NM, the high rate data link provides the required precision navigation (20 cm vertical accuracy). The F-35B/C requires an interim capability, a separate one-way data link, called the UHF Data Broadcast (UDB), which provides RelNav for the pilot out to 30 NM and supports precision approach out to 10 NM, as well as on-deck RF alignment.
JPALS brings a number of benefits to the fleet, some of which are presented below for the fixed wing pilot/LSO perspective:
? Once the pilot tunes in and the aircraft is processing the data link, he gets instant feedback that JPALS is up and running versus having to wait until flying into the ICLS/ACLS region behind the ship.
? JPALS slaves to the IFLOLS setting for nominal hook touchdown points for each cross deck pendant
allowing the pilot to not only change glide slope, but even target a specific wire. For MOVLAS, JPALS uses the last commanded IFLOLS HTDP [Hook Touch Down Point] setting prior to switching to MOVLAS.
? The legacy “System Waveoff” has been eliminated, so the pilot can degrade (and uncouple as applicable) to another approach means and not view a flashing W/O with a JPALS malfunction. Protection levels are established, but the platforms and aviation community are still developing specific degrades and alert indications.
? Air Boss/LSO initiated waveoff will continue to be displayed as a waveoff to the pilot within 1 NM and on final approach (except for F-35 with UDB).
? Although the system retains the legacy requirements of Closed Deck and CATCC waveoff, with the exception of the UDB system they are now displayed as a “Discontinue Approach.” The JPALS Incremental acquisition approach includes a non-GPS based back-up system.
Landing Signal Officer Display System (LSODS) Integration
JPALS interfaces with a number of legacy systems on the ship to provide operators the required information to conduct launch and recovery operations with JPALS equipped aircraft. The F-35 UDB does not have a surveillance downlink, so it depends on other systems to provide controller and LSO display information. As briefed at the LSO OAG this year, the F-35 UDB approach to the CVN will be limited to 300 ft. and ¾ NM, achieving only 200 ft. and ½ NM with an ACLS Mode III lock-on to display ACLS final approach data to the operators. The F-35 is implementing a flight director with UDB, but does not plan to couple the flight control system on UDB approaches....
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Program Coordination
In addition to the at-sea testing onboard CVN-77, JPALS testing continues ashore at the Landing Systems Test Facility in Patuxent River, MD. Although production JPALS will begin with CVN installs in 2015, it will take time for the C-2A, E-2D, F/A-18 E/F, EA-18G, and MH-60R/S platforms to integrate JPALS. CVN-79 is expected to deploy without SPN-46, so until that time, both JPALS and SPN-46 will co-exist during the transition.
PMA213 looks forward to continue coordination with OPNAV, platform OEMs, the air traffic controller and the LSO community to field a system that meets the operator needs as the next generation precision landing system. LSO involvement is critical to success, and details of aircraft integration procedures will continue to be briefed to the fleet for feedback."
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
28 Nov 2011, 01:30
