‘Bedford Array’ May Have F-35C Uses After All

Future Carrier Recovery Methods

http://www.hrana.org/documents/PaddlesM ... ly2011.pdf (2.2Mb)

“NAVAIR engineer Buddy Denham presented some interesting developments on how methods of carrier recovery may progress in the future, especially regarding the introduction of the next generation of carrier-based aircraft. What will the composition of a carrier air wing look like in 2020? How will these aircraft make their approach and landing on the CV? As F/A-18s begin to be replaced with F-35 and UCAS (and already-existing aircraft are equipped with JPALS), will Naval Aviation shift toward using ‘auto land’ systems as the primary method of aircraft recovery or still rely on the traditional technique of ‘Meatball, Line-up, Angle-of-Attack’ and pilot skill?

Initially, it was thought that the advanced navigation and guidance capabilities of UCAS and F-35 would allow for greater reliance (maybe even total reliance) on purely ‘auto land’ systems with the hope that this would eliminate pilot error as a causal factor in landing mishaps as well as significantly reduce pre-deployment FCLP requirements. However, a total reliance on automated methods of carrier landing would leave Naval Aviation vulnerable to signal jamming as well as GPS-denied environments.

Could their possibly be a ‘third way’ that would be so simple for the pilot to fly, yet not susceptible to jamming or electronic failure? What was proposed by Buddy Denham is the integration of a system called the Bedford Array Landing Reference System that would augment our current IFLOLS system. The system would consist of a series of high intensity centerline lights as depicted below: [PHOTO]

These lights would be approximately twelve feet apart and would shift in order to display not only glide slope information but also glide slope trends during the pass, similar to a PAPI or VASI but stabilized with regards to deck motion.”

[SEARCH THIS FORUM FOR 'Bedford' - most info in the very long thread]
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F-35 Joint Strike Fighter Carrier Integration
“LCDR Eric “Magic” Buus from VX-23?s F-35 Carrier Integration team gave an excellent update on the status of the F-35C (The Navy?s CV version). As would be expected from any carrier based aircraft, the F-35C will feature more structural integrity than the F-35A in addition to slightly larger control surfaces. Reference the specs below to see how the F-35C will compare to the F/A-18C and F/A-18E: [PHOTO]

As you can see, the F-35 will have wingspan similar to the Rhino but with a smaller flight deck footprint and a very impressive internal fuel capacity of more than 19,000 pounds. Currently two airframes have been delivered for testing and the third is expected to arrive soon. Some things that will take some getting used to will be the lack of a FLAPS switch and coming into the break with the hook up (Due to hook airspeed limitations). Also worth mentioning is the fact that as of now only the Air Force?s F-35A will feature and internal gun.

The F-35C will also not include a HUD and, like the F-16, will feature a side-mounted control stick. Most notably is the fully-customizable 8” by 20” touch screen that will replace the separate displays that Hornet and Rhino pilots have become accustomed to (See cockpit photograph featured below). Test pilots indicate that the F-35 is a very stable platform and overall flies “slightly better than a Hornet,” and initial Sea Trials are scheduled for the First Quarter of 2013.”
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JPALS Update
"The Joint Precision Approach and Landing System (JPALS) is a GPS-based system that will eventually replace the current radar-based methods of carrier approach and landing. It will be comprised of both ship and aircraft based systems and supported by a JPALS-specific data link. This system will become the Joint Service standard, completely interoperable across each military branch, and 100 percent compatible with the civilian GPS-based systems scheduled to replace ILS, NDB, and VORTAC navigational aids.

How will the carrier-based systems work? Basically, the ship provides precise GPS/INS measurements and other data such as hook touchdown points and glide slope information via the encrypted data link to the aircraft. This data is combined with data from the aircraft itself to determine its exact relative position. The relative positions of the aircraft and ship will then be used to display relative position in relation to glide slope and centerline to the pilot via standard cockpit in-strumentation.

The JPALS hook touchdown points (HTDPs) will be fully selectable and slaved to the IFLOLS. As of now, the system is being developed to allow for four possible commanded HTDPs for 4-wire ships and three for 3-wire ships. Each of these selectable HTDPs will be 20.4 feet prior to the target CDP on the 4-wire ships and 15.4 feet prior to the CDP on the three wire ships. Unfortunately, selectable HTDPs will not be available for field-based JPALS approaches. While this would be an excellent capability for “fly-in arrestments” at the field, FAA regulations would require a NOTAM be issued anytime the parameters of a precision approach changes.”

spazinbad
Initially, it was thought that the advanced navigation and guidance capabilities of UCAS and F-35 would allow for greater reliance (maybe even total reliance) on purely ‘auto land’ systems

I for one would be very surprised if future Navy pilots would come to rely (never mind TOTALLY rely, outside if a U.C.A.V.) on a automated landing system. The F/A-18 Hornet, F-14D Tomcat and the later models of the <a href="http://www.swordsmen.org/intruder.htm">A-6E Intruder</a> , (if I'm not mistaken) had the ability to "auto land" with Automated Carrier Landing System (not the forthcoming Bedford system obviously). But Navy dogma was not to rely on the ACLS. How much of that was due to keeping up pilot proficiency and how much was due to distrust in the reliability of the ACLS I can't say.

FlightDreamz, I don't know why you have misquoted the above information in your "spazsinbad" quote and I quote that now:
"spazinbad
Initially, it was thought that the advanced navigation and guidance capabilities of UCAS and F-35 would allow for greater reliance (maybe even total reliance) on purely ‘auto land’ systems of a system called the Bedford Array Landing Reference System"

The first part of your quote - only - is a proper quote - the last half of the purported quote in BOLD is NOT. You have misunderstood what the Bedford Array is all about. As stated in the above article and I'll quote: "Could their possibly be a ‘third way’ that would be so simple for the pilot to fly, yet not susceptible to jamming or electronic failure? What was proposed by Buddy Denham is the integration of a system called the Bedford Array Landing Reference System that would augment our current IFLOLS system. The system would consist of a series of high intensity centerline lights as depicted below: [PHOTO]

These lights would be approximately twelve feet apart and would shift in order to display not only glide slope information but also glide slope trends during the pass, similar to a PAPI or VASI but stabilized with regards to deck motion.”

This Bedford Array is a Visual System. I'm reluctant to constantly refer that people ought to search this forum for information that exists here. However I may make available a bunch of PDF pages and attach them to this message for your convenience (and mine).
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Addition: Decided to just point to existing information so if an avid reader will start here with some Shipborne Rolling Vertical Landing info (the reason for the Bedford Array) then perhaps how it MAY be used as indicated above for USN (RN) F-35Cs may make more sense perhaps:

http://www.f-16.net/f-16_forum_viewtopi ... t-150.html (SCROLL DOWN)

Next Page has more etc.: http://www.f-16.net/f-16_forum_viewtopi ... t-165.html
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Addition: Precise information about the Bedford Array on this page which is repeated here also: http://www.f-16.net/f-16_forum_viewtopi ... t-210.html

The Bedford Array will enable Shipboard Rolling Vertical Landings SRVL. Explained at various places: http://content.yudu.com/A10pvz/WTJan200 ... ces/28.htm "Warship Technology Jan 2009"
specifically
http://content.yudu.com/A10pvz/WTJan200 ... ces/28.htm
&
http://content.yudu.com/A10pvz/WTJan200 ... ces/29.htm
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Janes Defence Weekly 04 March 2009: (graphic from URL below)

http://www.zinio.com/reader.jsp?issue=3 ... v=sub&p=28
&
http://www.zinio.com/reader.jsp?issue=3 ... v=sub&p=29

There may be other helpful additions to IFLOLS (mirror) as well as the Bedford Array but to me it seems a good idea easily enough implemented most likely. I refer the gentle reader to this page (a long article): http://www.f-16.net/f-16_forum_viewtopi ... t-240.html

Preparing for take-off: UK ramps up F-35 carrier integration effort

http://militarynuts.com/index.php?showtopic=1507&st=120

QUOTE: "RAY OF LIGHT: COMPLEMENTARY VLA SOLUTIONS FOR ALTERNATIVE RECOVERY MODES
The purpose of a landing aid system is to assist the pilot during approach and recovery to the ship by day or night. As baselined for STOVL operations (with emphasis on a vertical recovery manoeuvre), the CVF design includes a Glide-slope and Long-range Line-up Indicator System (GLIS), a HIHAT and light emitting diode flight deck lighting. AGI has been contracted by the ACA to supply these as part of a GBP7.5 million (USD11.5 million) contract for the supply of visual landing aids (VLAs) for both fixed- and rotary-wing aircraft.

The GLIS system, based on two night-vision goggle-compliant stabilised Glide Path Indicator (GPI) units, is the primary source of information available to the pilot for establishing and maintaining the correct glide slope during the approach. These GPI units are positioned at either end of the ship, in the port catwalk level with the flight deck. High intensity drop-line lights, mounted on the stern of the ship, provide line-up cues.

Each GPI is essentially a high intensity sectored light projector. The glide slope of the aircraft, relative to the GLIS, determines which coloured light sector is visible to the pilot. If the pilot is flying down the optimum glide slope (nominally three degrees) a steady green light is visible. If the approach is too high a flashing green light is visible. Alternatively, if the approach is too low a red light will be visible. A steady red light indicates a slightly low approach and a flashing red light indicates a very low approach.

HIHAT consists of 11 lights fitted in a vertical stack with two standard deck lights mounted horizontally, one either side of the stack, at the optimum aircraft hover height (which aligns to the fourth vertical light, thus resulting in three lights above this position and seven below).

Light output from each of the vertical lights is designed such that it can only be seen when level with or above the centre line of the light; it cannot be seen from below this level. Thus if the unit is viewed at the optimum hover height then a T shape, consisting of the vertical stack of lights horizontal deck lights, will be seen. Moving above this position will result in more vertical lights being observed and a decrease in height will have the opposite effect, though the horizontal reference will still be visible. The spacing of the lights will also give a clear indication as to the rate of ascent or descent as more lights are illuminated or extinguished, and the rate at which this occurs.

Whilst the HIHAT is primarily intended to be used once the aircraft is over the deck and in the hover phase of the flight, it is anticipated that pilots will acquire the HIHAT at anything up to 0.5 n miles from the ship. The system is intended to complement the information obtained from GLIS and between them will provide a complete visual approach aid for a vertical recovery.

With SRVL now likely to be used as a recovery technique on board CVF, there is an additional requirement to augment the baseline VLA suite with a landing aid appropriate to the SRVL approach manoeuvre. To this end QinetiQ has undertaken research into a new VLA concept, known as the Bedford Array, which takes inputs from inertial references to stabilise against deck motions (pitch and heave).

A trial of the concept was undertaken aboard the aircraft carrier HMS Illustrious in November 2008, with QinetiQ using its Harrier T.4 VAAC testbed to fly approaches to a demonstration Bedford Array mounted on the ship. For the purposes of the trial, the lighting array was installed in the port catwalk adjacent to Illustrious's flight deck. The VAAC Harrier did not actually perform SRVL recoveries to the ship owing to the limited dimensions of the flight deck, but flew representative SRVL approach profiles to the catwalk array (down to a safety height of about 40 ft above deck) to evaluate its ability to accurately indicate an SRVL glide scope aimpoint to the SRVV.

A second lighting array was rigged on the carrier flight deck itself. This was used for a parallel evaluation of the visual acuity of the lighting system on deck...."
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Addition: More on these diverse systems on this page:

Helicopter Visual Approach System (HELIVAS) perhaps useful for F-35Bs on LHA/Ds [don't be confused by reference to LHA/D - remember we are innovating here]

http://www.f-16.net/f-16_forum_viewtopi ... t-360.html

spazsinbad
FlightDreamz,
I don't know why you have misquoted the above information in your "spazsinbad" quote and I quote that now:
"spazinbad
Initially, it was thought that the advanced navigation and guidance capabilities of UCAS and F-35 would allow for greater reliance (maybe even total reliance) on purely ‘auto land’ systems of a system called the Bedford Array Landing Reference System"

The first part of your quote - only - is a proper quote - the last half of the purported quote in BOLD is NOT. You have misunderstood what the Bedford Array is all about.

Spaz My sincere apologies! I mistook your original post to be about a newer (GPS based?) automated landing system that the U.S. Navy is replacing the current automated landing system with (as I believe you have already noticed) and then compounded the error with a sloppy cut and paste job on the quote. Didn't mean to put words in your mouth.
I was completely on the wrong track (again my apologies)! Off to read the material you thoughtfully provided and wash the egg off my face.

FlightDreamz, no worries. I became a bit tetchy at being misquoted and it was not even me. Understand about misunderstanding. The F-35 of all persuasions brings a lot of new 'off the aircraft tech' into being at some stage. Things are going to be a lot different in a few years most likely. I forgot to add some info about the ACLS. Yes it is not used that much but when needed it is useful. For example here is one quote:

“Automatic Carrier Landing System (ACLS). My info is fairly old and may have changed but in a "Mode 1" approach the plane is completely coupled to the ships ACLS data link system. If you ever hear someone call the ball and add "coupled" to the end they are flying Mode 1 (the "auto" call is for when auto-throttles are being used). Mode 1 doesn't get used all that much for a few reasons. First of all, if the ship is even slightly moving around it is uncomfortable. Picture a laser beam being projected out from the 3 wire that represents the aircraft's proper glidepath. Now imagine what that beam does as the boat pitches and rolls in the water. ACLS will keep the jet on that beam, and it can make for a wild ride. Also, the pass won't count toward the pilots grade average. You will generally see guys using Mode 1 after long combat missions where they don't want to mess around and just want to get back aboard.”

http://www.fsdreamteam.com/forum/index. ... 1.msg0#new
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A long article about history of ACLS is here: www.tsretirees.org/memory/Femiano.doc

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There are an array of approaches as indicated in the graphic from this link:

https://www.cnatra.navy.mil/ebrief/docu ... NATOPS.pdf

This is for the MODES graphic: http://ftp.rta.nato.int/public//PubFull ... 162-07.pdf
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Night time is the right time for Case III: "“CASE III: This approach shall be utilized whenever existing weather at the ship is below Case II minimums and during all flight operations conducted between one-half hour after sunset and one-half hour before sunrise except as modified by the OTC or carrier commanding officer. Night/IMC Case III recoveries shall be made with single aircraft. Section approaches will be approved only when an emergency situation exists. Formation penetrations/ approaches by dissimilar aircraft shall not be attempted except in extreme circumstances where no safer options are available to effect a recovery.”
CV NATOPS 2009 NAVAIR 00-80T-106: https://www.cnatra.navy.mil/ebrief/docu ... NATOPS.pdf

The 'Femiano.doc' has some interesting history about 'automatic landings'.

AUTOMATIC CARRIER LANDING SYSTEM (ACLS) by Don Femiano

http://www.tsretirees.org/memory/Femiano.doc

“LOOK MA NO HANDS.” This was the slogan on a jacket patch created by Bell Aerosystems on the occasion of the US Navy’s Operational Certification of Bell’s Automatic Aircraft Landing System (ACLS). It contains the caricature of a pilot flying a plane with his arms folded as he approached an aircraft carrier. Unfortunately, the patches are not around any more, but the Bell ACLS is in operational use on all Navy aircraft carriers to this day.

This success didn’t happen over night. It was the result of several years of effort by many at Bell starting in 1953 when Bell, using a feasibility model landing system, won a fly off competition with Minneapolis Honeywell. Following this win, Bell won a contract to build a shipboard feasibility model system, designated AN/SPN-10 (XN-3), for testing aboard Navy aircraft carriers. Using the (XN-3) system, the first automatic landing with a Navy aircraft took place in 1954, at the Niagara Falls Airport, adjacent to the Bell facility in Wheatfield New York. In 1957, the first automatic-landing-to-touchdown, on a carrier, was accomplished with the (XN-3), by a Navy pilot in an F-3D aircraft on USS Antietam (CV-36)....

...In 1962, the first production systems were installed on USS Midway (CV-41) and USS Independence (CV-62) and, in 1963, after certification testing at sea on USS Midway, AN/SPN-10 was certified for operational use. Over the next several years, production systems were installed on the Navy’s aircraft carriers operating at that time.

Unfortunately, the reliability of the system was low because it consisted of more than thirty units of electronic equipment, containing hundreds of vacuum tube operational amplifiers, to perform ship motion stabilization and the aircraft control computations. As Bell and the Navy sought ways to improve the system, it was obvious that digital computers and solid-state electronic technology were the only solutions to the reliability problems....

...While the AN/SPN-42 was in development, an AN/SPN-10 field change that reduced electronic equipment to improve reliability was installed in the system. Unfortunately, this change eliminated the automatic touchdown capability, but the system would still control aircraft to carrier approach minimums, and the pilots would land the aircraft manually....

...In 1984, extensive testing of the AN/SPN-46(V)1 was conducted at the Naval Air Warfare Center Aircraft Division (NAWCAD), Patuxent River, MD, with several Navy aircraft.

In 1985, the first system was installed on USS John F Kennedy (CV-67) and OPEVAL sea trials were conducted in 1986 and 1987 with F-14 Tomcats. In 1987 The Navy awarded the AN/SPN-46(V)1 Operational Approval for full automatic control from aircraft acquisition at ten nautical miles to touchdown on the deck and production of the system was started...."

Article goes on to say how system has been upgraded and life cycle extensions all to be replaced by JPALS as soon as....

As indicated in a recent thread about X-47B auto land landings here is info about the first Hornet complete auto land with the new system in 2007:

Super Hornet Demonstrates Unpiloted Approaches [emphasis on the 'no pilot/robotic']

http://www.aviationweek.com/aw/jsp_incl ... Approaches

Some of the article quoted: "...There were no changes to the flight control laws of the F/A-18F for this phase of the program.

"This was mostly about autonomous command and control with an existing, carrier-qualified platform and demonstrating we could control it from the ship," Davis says. "For future activities, we may incorporate modifications to make the Super Hornet more representative of a tailless flying wing."

That may differ very little from a manned aircraft's approach, except that an unmanned aircraft can operate at a higher angle of attack because there's no need for a pilot to have forward vision.

"This design would actually approach the ship slower [less than 140 kt.] than the Super Hornet does today," says George Muellner, president of Advanced Systems within Boeing Integrated Defense Systems. "If you look at the Super Hornet and the [F-35 Joint Strike Fighter], the actual come-across-the-end-of-the-deck characteristics are different from the standpoint of what factors on the aircraft produce them. But the end results are very similar."

May's demonstration on the Truman was dictated by the flight characteristics of the Super Hornet.

"We were flying about an 8-deg. angle of attack, 3.5-4-deg. glideslope and an approach speed of about 135-142 kt.," Davis says. "We weren't pushing the boundaries with this first set of demonstrations."

One of the most crucial areas for a tailless airplane as it approaches the back of the carrier is flying through the burble. (The burble is a region of turbulence created by the carrier.)..."
&
"...Flying to an arrestment on the deck will have to wait until a precision, Differential GPS system is installed on the aircraft and the ship. However, the follow-on phases are planned. The technology is expected to benefit not just the UCAS program but virtually any aircraft that lands on an aircraft carrier. As a result, Boeing will help with risk reduction on the Navy's Precision Approach and Landing Systems (JPALS) development, as it would work with the Super Hornet and F-35 Joint Strike Fighter. It then could be further modified to work with whatever design is selected for the advanced unmanned strike program...."

Bedford Array Patent (QinetiQ) Explanation: http://www.freepatentsonline.com/20110121997.pdf (102Kb)

Have the Brits installed the Qinetiq Bedford Array on the new carriers?
I can find no documents that it was ever used for landings.
I don't think the US will ever apply this technology.

The brits have not decided a lot about the new deck configuration for the amended CVF. Probably the first one will not be configured for anything other than helo ops (but yet to be decided) with only the second CVF being changed to CATOBAR ops. However these very specific details are all undecided at moment, as is the usual brit thing to do these days. Yes - broad decisions made but details unknown.

The very long thread has plenty of documentation about Bedford Arrays being tested on 'through deck cruisers' but SRVL landings could not be done on the short decks with the VACC Harrier simulating the F-35B. Have a look at the first page of this thread/topo of this page for futher details.

You may think what you wish but professional USN LSOs have been thinking about this technology as described on the first page of this thread. That is the point of this thread. Today I'll attempt to extract the text from the PDF to post here (rather than have only an image of the text). In the explanation it is clear about the advantages as described when used with HUDless AoA Indexerless F-35 aircraft, with pilot not having to look anywhere other than straight down the angle deck - remembering he has to start looking to the left to follow the mirror/IFLOLS to touchdown so as to not 'deck spot'.

Google Searching for Bedford Array is a good choice. Here is onesuch:

http://www2.qinetiq.com/home/newsroom/n ... dford.html

QinetiQ proves its innovative Bedford Array visual landing aid on HMS Illustrious 16 December 2008

"Trials prove novel QinetiQ solution for F-35B ‘rolling landings’ on Royal Navy’s future aircraft carriers in high sea state conditions

QinetiQ has successfully completed a series of trials using its T4 Vectored-thrust Aircraft Advanced Control (VAAC) Harrier aircraft on HMS Illustrious. These proved QinetiQ’s innovative new Bedford Array visual landing aid system – which stabilises the aircraft’s approach path in the presence of deck motion – as the solution for Shipborne Rolling Vertical Landings (SRVL) on the Royal Navy’s future carriers, particularly in rough sea state conditions.

The UK Ministry of Defence has been funding ongoing research to refine and de-risk the use of SRVL approaches for its new jump jet – the F-35B Lightning II Short Takeoff and Vertical Landing (STOVL) Joint Strike Fighter (JSF), the UK MOD’s preferred choice to meet its Joint Combat Aircraft requirement. The MOD plans to operate up to 36 JSFs from each of its two new future aircraft carriers:- HMS Queen Elizabeth, currently expected to enter service in 2014 and HMS Prince of Wales in 2016.

An SRVL landing involves a STOVL aircraft executing a ‘rolling landing’ onto the carrier flight deck, using air speed to provide wingborne lift to complement engine thrust. No arrestor gear is deployed as the aircraft uses its own brakes to stop. Compared to a standard vertical landing, an SRVL recovery offers real advantages for the F-35B as heavier payloads can be brought back and safely landed onboard ship. It also has the potential to reduce propulsion system stress and therefore extend engine life.

Early studies showed that the F-35B has a critical vulnerability to deck motion for the SRVL manoeuvre and that this type of landing is not viable in all desired conditions. As a result, the MOD placed a contract with QinetiQ in 2007 to analyse the root cause of the problem and design a solution.

QinetiQ’s new Bedford Array visual landing aid system was conceived, developed and fully tested in around a year in direct response to MOD requirements. The system ensures that the pilot flying the ‘rolling landings’ makes an accurate approach to the deck, even in rough sea conditions. It takes inputs from external passive references and when combined with information in the pilot’s Helmet Mounted Display, allows for a low workload, stabilised pilot approach in even the worst conditions.

“The UK has an incredible heritage of innovation in naval aviation and pioneered many of the things now taken for granted in the conventional carrier world,” explained QinetiQ test pilot Justin Paines, who flew the X-35B Joint Strike Fighter Concept Demonstration Aircraft. “With the Bedford Array, we’ve done it again and developed an approach aid that has application beyond F-35B to other forms of embarked aircraft recoveries. We have already received interest from other countries involved in naval aviation.”

QinetiQ’s VAAC Harrier flew a total of 39 sorties in the southwest approaches between 12-19 November to prove the Bedford Array landing system – in all 67 vertical landings and around 230 SRVL approaches were flown.

“This series of trials was designed to refine the operational concept, mitigate failure cases and optimise QinetiQ’s innovative Bedford Array visual landing aids arrangement,” explained Lt Cdr Chris Götke, one of the test pilots who also marked his 400th vertical landing during the trials. “The MOD turned to QinetiQ to solve this significant problem of landing laden aircraft in rough seas. This ingenious solution was first tested in QinetiQ labs and has now been proved by these hugely successful trials and will be implemented on the new carriers.”

In mid-2007, a series of VAAC trials were conducted onboard the French aircraft carrier Charles de Gaulle to establish the fundamental safety, operability and operational benefit of the SRVL technique. The recent trials on HMS Illustrious could prove to be the last research tasking for QinetiQ’s VAAC testbed as the aircraft is now 39 years old, and is expected to be retired from service in early 2009.

For this series of trials the Bedford Array was installed in the port catwalk adjacent to HMS Illustrious’ flight deck, but due to the limited dimensions of the deck, SRVL recoveries were not preformed – instead a low go-around was flown. A second lighting array was also installed on the carrier flight deck and used for a parallel evaluation of the visibility of the lighting system in differing ambient conditions."

Here is the automatic OCR from the original Patent PDF as seen above. The text has not been proofread [text here compared to original PDF] (life too short) but it should give the gist about what is actually in the original Patent PDF. Some parts of the text may be in bold due to MY emphasis [or referring to numbers in numbered diagrams].

United States Patent Application Publication | Pub. No.: US 2011/0121997 A1 |
Pub. Date: May 26, 2011
Visual Landing Aids | Inventor: Justin David Billot Paines, Austy (GB) |
Assignee: QINETIQ LIMITED

ABSTRACT [none of the text has been proofread from automatic OCR]
A visual aid for the pilot of an aircraft approaching to land on an aircraft carrier comprises a series of lights (9) embedded along the landing deck and controlled in response to pitch and heave of the vessel so that the light(s) illuminated at any time indicate a visual aim point which is stabilised with respect to a specified glideslope (5) onto the vessel irrespective of such vertical excursions of the vessel. It is used in conjunction with a marker on a head up display or helmet mounted display for example so that registry of the marker with the illuminated light at any time indicates that the aircraft is on the correct glideslope.

VISUAL LANDING AIDS

http://www.freepatentsonline.com/20110121997.pdf

[0001] The present invention relates to visual landing aids (VLAs) and more particularly to a visual aid for the pilots of aircraft approaching to land on moving platforms, notably vessels at sea such as aircraft carriers or other ships which can accommodate aircraft landings of the type more particularly described herein.

[0002] The invention has been conceived particularly, though not exclusively, as an aid for use in executing ship­board rolling vertical landings. The so-called rolling vertical landing (RVL) is a type of landing executed by vectored­ thrust vertical/short takeoff and landing (V/STOL) and short takeoff and vertical landing (STOVL) aircraft as an alterna­tive to a normal vertical landing, in which the aircraft approaches at an angle to the ground and at relatively slow speed (in comparison to conventional fixed-wing landings) under a combination of jet-borne and wing-borne lift. Aircraft of this class include the well known V/STOL Harrier and Sea Harrier "jump jet" variants, and the STOVL F-35B variant of the Lightning II yet to enter service. The RVL was developed originally as a manoeuvre for landing on unprepared areas in land-based operations so that debris disturbed by the jet efflux would tend to be blown behind the aircraft and not into the engine intakes. It is also considered to be a useful technique for shipboard operations, however, due to the ability to land with a higher aircraft weight than would be possible in the same meteorological conditions if a vertical landing was to be used, or to land at the same weight but with a reduced power setting as compared to the vertical landing thereby potentially increasing engine life. Other benefits can include a reduction in the erosion of deck coverings by engine exhaust as com­pared to vertical landings. While conceived with shipboard RVLs by V/STOL and STOVL aircraft in mind, however, the present invention may also find application as an aid for conventional (wire-arrested) fixed wing carrier-borne land­ings which are typically conducted with shallower approach angles and at substantially higher speeds than RVLs, and also for helicopter landings if not performed vertically.
[0003] Note: all references in this specification to landing directions, approach angles, glideslopes etc. in the context of landings on vessels which may be underway are to those directions, angles, glideslopes etc. relative to the overall mov­ing platform and not to the actual movement of the aircraft through the air.

[0004] A VLA currently in service with some navies for conventional fixed wing carrier-borne landings is the so-called Improved Fresnel Lens Optical Landing System (IFLOLS). This comprises a set of lights located on the deck offset laterally from the runway and directed towards approaching aircraft. There is a horizontal row of datum lights to either side of a central vertical column of indicator lights which are selectively lit so that at any time the position of the illuminated indicator light (known as the "ball") relative to the datum lights indicates to the pilot whether he is above, below or upon a specified glideslope. This can be stabilised for pitch, roll and heave of the deck with the apparatus being tilted on gimbals as required to maintain its indication of the correct glideslope. It requires the pilot to scan laterally away from the runway centreline to use the aid, however, and sig­nificant training is required in order to prevent pilots from inadvertently reacting instead to deck motion, known as [b]"deck spotting". It is also expensive to maintain due to the number of moving parts, and occupies useful deck space.

[0005] The present invention, on the other hand, seeks to provide a VLA which imposes a lower mental workload on the pilot and consequently involves less of a training burden than the IFLOLS, does not require him to scan laterally away from the runway, and in a preferred embodiment involves no moving parts and does not occupy otherwise useful desk space.

[0006] The invention is predicated on the provision of a visual aim point on the platform which when in registry with a visual marker on or in the aircraft indicates that the aircraft is on a specified glideslope to touch down at a point related to the aim point. With any such arrangement it is however nec­essary to consider the effect of excursions of the platform in the vertical sense for which purpose reference will be made to the accompanying schematic FIGS. 1 and 2 (not to scale and wherein for ease of illustration the depicted glideslopes are much steeper than those which can be expected in practice).

[0007] FIG. 1 indicates in full line the deck 1 of an aircraft carrier in a nominal level (equilibrium) condition and the line 2 indicates the glideslope down which an aircraft 3 has to fly with the deck in this condition to arrive at a specified main­wheel touchdown point 4 at a specified approach angle. Sup­pose the vessel pitches with the bow down and the stern up so that the deck is now in the attitude indicated in chain line, 1A. The touchdown point 4 is accordingly now above its position in space with the level deck and the glideslope down which the aircraft would have to fly in this condition to arrive at the same point 4 at the specified approach angle is indicated by the line 2A. Conversely suppose the vessel pitches with the bow up and the stern down so that the deck is now in the attitude indicated in chain line, 1B. The touchdown point 4 is accordingly now below its position in space with the level deck and the glideslope down which the aircraft would have to fly in this condition to arrive at the same point 4 at the specified approach angle is indicated by the line 2B. In other words it will be appreciated that if the pilot is to attempt to touch down at the specified point 4 while the vessel is pitching he will have to constantly adjust the position of his glideslope throughout the approach. This could be achieved by follow­ing a fixed visible aim point on the deck (in practice located somewhat forward of the point 4 in the usual case where the pilot is accommodated forward of the main landing gear) but would place a significant burden on the pilot at a critical phase of his mission. Similar considerations apply to excursions of the deck 1 in the vertical sense due to other ship motions, notably heave, or to any combination of causes.

[0008] FIG. 2 illustrates an alternative approach where instead of requiring touchdown at a single fixed point on the deck 1 the glideslope 5 is itself stabilised in space. It follows that for the illustrated range of deck excursions there will be a range of possible touchdown points depending on where the deck intersects the glideslope at the actual moment of touch­down. For example with a level deck 1 touchdown will occur at point 6, with the deck raised as at 1A touchdown will occur further aft at point 7, and with the deck depressed as at 1B touchdown will occur further forward at point 8.

[0009] It is to an approach of the kind exemplified in FIG. 2 that the present invention is directed and it will be appreciated from the foregoing discussion that the use of a single fixed aim point on the deck will be insufficient to establish the aircraft on the desired fixed glideslope when subject to excur­sions in the vertical sense due to pitch, heave or the like.

[0010] Accordingly in one aspect the invention resides in a visual aid for the pilot of an aircraft approaching to land on a moving platform comprising means for defining a visual aim point on the platform and means for adjusting the apparent position of such visual aim point along the platform in response to excursions of the platform in the vertical sense so that registry of the visual aim point with an associated visual marker on or in the aircraft at any time indicates that the aircraft is on substantially the same specified glideslope fixed in space relative to the overall platform irrespective of such excursions thereof.

[0011] The visual aim point in such an arrangement could be represented by a distinctive object which is physically translated back and forth along the platform as required in use of the aid, or even an object which is moved vertically up and down from a fixed position on the platform (but would have to be fully retracted at the moment of touchdown or would represent a collision hazard). Preferably however the aid comprises an array of lights which are distributed along the platform and arranged to be lit selectively to indicate the position of the aim point at any time.

[0012] In one arrangement the aim point indicator lights are arranged in a row or parallel rows along the platform and controlled such that the light in the or each row which is nearest to the intended aim point at any time is lit. In another, those lights are arranged in a row or parallel rows along the platform and controlled such that a single light is lit in the or each row when the intended aim point is within a specified distance of that light and two successive lights are lit in the or each row when the intended aim point is within a specified distance of the mid point between those two lights. In any event, lights may also be lit to indicate the effective limits of the array at any time.

[0013] An array of aim point indicator lights may also extend along a length of the platform such that different longitudinal sections thereof are capable of functioning to provide an adjustable aim point for a plurality of specified glideslopes fixed in space in different positions along the platform.

[0014] Typically the associated visual marker on or in the aircraft will be presented in a head up display (HUD) or helmet mounted display (HMD) and comprise a marker rep­resenting a depression angle from the horizon equal to the specified glideslope angle. Other arrangements are possible, however, such as an equivalent marker in a cockpit display from a forward-looking camera or simply a physical marker on part of the aircraft structure which is positioned relative to the pilot eye-point at the required fixed depression from the horizon when the aircraft is in the correct approach attitude.

[0015] In another aspect the invention resides in a visual aid for the pilot of an aircraft approaching to land on the deck of an aircraft carrier or the like vessel comprising means for defining a visual indication on the deck and means for adjust­ing the apparent position of such visual indication along the deck in response to excursions of the vessel in pitch so that when viewed along a specified sightline from the aircraft said indication corresponds to the aftmost limit at which the air­craft will safely clear the stern of the vessel when following a specified glideslope parallel to said sightline irrespective of such excursions of the vessel.

[0016] In another aspect the invention resides in a method of approaching to land an aircraft on a moving platform by use of a visual aid as defined above.

[0017] The invention will now be more particularly described, by way of example, with reference to the following accompanying drawings, in which:

[0018] FIG. 3 illustrates the principle of the invention sche­matically and not to scale (and wherein for ease of illustration the depicted glideslope is much steeper than that which can be expected in practice), as implemented with an array of indi­cator lights;

[0019] FIG. 4 is a schematic block diagram of the control system for the indicator lights in a VLA according to the invention;

[0020] FIG. 5 is a plan view of one embodiment of an indicator light array for use in a VLA according to the inven­tion;

[0021] FIG. 6 indicates an example of the pilot's eye view when using a VLA according to the invention; and

[0022] FIG. 7 illustrates an optional lighting logic for use in a VLA according to the invention.

[0023] Referring to FIG. 3 the aircraft 3 is shown with a specified mainwheel glideslope 5 fixed in space relative to the deck 1 and a possible range of touchdown points such as 6, 7 and 8 corresponding to a range of vertical deck excursions similarly to FIG. 2. Let into the deck along a length forwardly offset from the touchdown point range is an array of aim point indicator lights 9. In the course of the approach the pilot observes the lights 9 in conjunction with a marker presented in, say, a HUD or HMD and representing a depression angle from the horizon equal to the angle of the glideslope 5, or in other words along a sightline 10 parallel to the glideslope. As the deck pitches, heaves or otherwise moves in the vertical sense the lights 9 are selectively illuminated so that at any time only that light which is on (or closest to) the intended sightline 10 is lit, as indicated in the Figure ("filled" light=lit). For example in the nominal level deck condition (1) the central light is lit, at the maximum upward deck excursion (1A) with which the system is intended to operate the rear­most light is lit, at the maximum downward deck excursion (1B) with which the system is intended to be used the fore­most light is lit, and so on. In other words while the aim point represented by the illuminated light moves relative to the deck as the deck moves up and down with ship pitch, heave etc it remains in a substantially fixed position with respect to an observer in the plane of the glideslope 5 (i.e. as viewed along the sightline 10), and by controlling the aircraft to keep whichever light is lit in registry with his specified HUD/HMD marker the pilot can be confident that the aircraft is correctly following the glideslope 5.

[0024] As schematically illustrated in FIG. 4, in order to control the illumination of the lights 9 for the above purpose information on the motion of the deck is derived from a suite of conventional inertial and/or ring laser gyro and/or satellite positioning sensors 11 and fed to a processor 12 which com­putes the correct position within the light array to illuminate from this data and knowledge of the desired glideslope. The processor drives a light controller 13 which in turn switches power to whichever of the lights 9 is to be illuminated at any time.

[0025] FIG. 5 illustrates one practical example of an aim point light array for use in a VLA according to the invention. In this case the indicator lights 9 are arranged in pairs to either side of the runway centre line, in a "tramline" arrangement, and conventional "tramline" lights (typically at greater lon­gitudinal spacings than the aim point lights 9) are also seen at 14. Extra lateral lights as shown at 15 can also be provided to indicate the limits of the aim point array.

[0026] FIG. 6 indicates an example of the pilot's eye view when approaching to land on an aircraft carrier and using an aim point light array similar to that of FIG. 5. "Tramlines" 16 are painted on the deck to either side of the runway centreline. Lights similar to those indicated at 14 in FIG. 5 will be spaced along these "tramlines" but are not shown separately in FIG. 6. Two lateral rows of limit lights 15 are however shown and between them a pair of illuminated aim point lights 9 which in this case are bar shaped, the other members of the aim point light array which are not illuminated at the instant depicted in FIG. 6 not being shown. HUD symbology visible to the pilot is also shown including a ship referenced velocity vector symbol (circle) 17 and a marker (pair of bars ) 18 representing a depression angle from the horizon corresponding to the desired glideslope angle; (other conventional HUD symbol­ogy which will usually be present in the pilot's display is omitted for ease of illustration). In principle the invention can be used with any practical glideslope angle which may be chosen in any case with regard to the operational require­ments, prevailing meteorological conditions, aircraft perfor­mance and characteristics etc. In the example of FIG. 6, however, a 6° angle is assumed, which is considered to be a practical option for shipboard RVLs. The HUD 6° marker 18 is shown to be in near registry with the illuminated aim point lights 9 showing that the aircraft is established on the correct glideslope to within an acceptable degree of error.

[0027] The VLA according to the invention and exempli­fied by FIG. 6 offers a compelling visual cue which can be easily and intuitively interpreted by pilots without significant specific training. In simulation trials pilots have found it relatively easy to follow the guidance provided by this aid without being distracted by deck motion. Unlike the IFLOLS it allows the pilot to concentrate his visual scan through the HUD or HMD without having to scan to a laterally offset position to use the aid. The array of aim point indicator lights need not involve any moving parts and should have much lower maintenance costs than the IFLOLS. The individual lights can be let into the deck and provide no obstruction to the aircraft on its landing rollout or to any other movements on the deck. The light array can easily be made night vision device compatible and support operations during both day and night.

[0028] Returning to FIG. 5, the required overall length of the aim point indicator light array 9 is determined by (i) the maximum range of deck excursions in the vertical sense that can be expected under the conditions in which the aid is to be used and (ii) the desired glideslope angle. For example from consideration of typical aircraft carrier deck motion data it is estimated that a total length of around 120 ft (36.6 m) would be required for operation in up to sea state 6 ("very rough"­significant wave height 4-6 m) with a 6° glideslope angle. In use the length of the array will be apparent to the pilot from the presence of the limit lights 15 and the position along the array of the indicator light pair which is illuminated at any time can provide situational awareness of deck motion, as well as an early indication (as the aim point comes close to the end of the array) that the deck motion is approaching a maxi­mum condition and likely to reverse its direction or else continue to an out-of-limits condition because sea conditions have exceeded those for which the aid is designed or for which it is safe to land. The limit lights 15 may also be caused to flash to give an unequivocal signal to the pilot if such an out-of-limits situation arises. Knowledge of the limits of the array indicated by the lights 15 can also allow the pilot to assess easily if any error in his sightline is on the safe side of the aim point or the reverse (an error on the safe side would be with the HUD/HMD marker lagging the aim point as it moves towards one of the limits of the array).

[0029] While FIG. 5 depicts a discrete light array which may be installed at a specified location on the deck, however, it may be desirable to provide an array which can cater for a range of different fixed glideslope positions relative to the deck so as to guide landing aircraft to touchdown further forward or aft depending on operational requirements or meteorological conditions. This can be provided by extend­ing the array of lights 9 along the deck to the extent required but only using a section of it as the "active" array at any time. The limits of the "active" array could be indicated by provid­ing additional lateral sets of limit lights 15 along the deck although this would increase the cost and complexity of the installation and constrain the range of possible "active" arrays unless a large number were installed. A simple alternative would be to use pairs of the aim point indicator lights 9 themselves permanently lit to indicate the limits of the "active" array at any time (or flashing in the event that an out-of-limits situation arises as discussed above for the limit lights 15). In any event the ultimate forward and rearward limits of any such array(s) as described herein will be deter­mined having regard to (i) the distance required for the air­craft to safely come to a stop after touchdown sighted by the foremost aim point (it being understood that aircraft conduct­ing SRVLs will not be wire-arrested) and (ii) ensuring that the aircraft safely clears the stern of the ship in its anticipated worst-case pitched up condition when sighting on the rear­most aim point.

[0030] It is also proposed that the aft limit of the array can itself be "active" in that it is calculated in real time from the sensed deck pitch motion and may accordingly move forward or back, with corresponding illumination of the applicable array lights 9 to indicate the aftmost possible position ofthe aim point for safe stern clearance on the specified glideslope under the actual conditions prevailing at any time. For example if the stern pitches up the aft limit will move forward, while the aim point will be moving aft in this situation. Should the two positions meet the corresponding array lights will flash as described above to signal that the glideslope is no longer stabilised and unless the pilot alters the flightpath of the aircraft to keep the HUD/HMD depressed aim marker within a specified degree of error of the flashing array lights, stern clearance is, at least temporarily, not guaranteed. The pilot may choose to abort the approach. An advantage of this "active" aft limit indication is that it ensures protection against a stern strike under all actually prevailing conditions and it follows that the nominal aim point can be positioned further aft, e.g. to maximise the available rollout distance, than when using a fixed array limit for which an additional safety margin must be built in to cater for possible, but unlikely, worst-case conditions. To avoid possibly distracting constant motion of an "active" aft limit, however, it could also be controlled to remain fixed in a location where it does not compromise the aim point location for the majority of deck motion but is able to move forward should deck motion dic­tate.

[0031] An "active" aft limit indication as discussed above may also have utility in situations where it is desired to provide stern clearance confidence to pilots approaching to land on an aircraft carrier or the like but not necessarily in combination with a stabilised aim point, and is consequently an independent aspect of the present invention.

[0032] It will be appreciated that the "resolution" of an aim point indicator light array 9, in terms of the accuracy with which a light actually intersects the sightline 10 at any time and any consequent "steppiness" in the changes between illuminated light positions as perceived by the pilot when established on the correct glideslope, depends on the longi­tudinal separation between each light pair. Simulator trials have shown that separations in the range of around 12-18 ft (3.7-5.5 m) are quite satisfactory when practised with a 6° glideslope angle. However it is possible to double the sepa­ration distance, thereby substantially reducing the number of lights required, and still achieve the same effective resolution, or to double the effective resolution for a given separation distance, if the following lighting logic is used. That is to say FIG. 7 shows four members 9A-9D of an array of this kind along one of the "tramlines" and instead of lighting only one of the lights at any time depending on which is nearest to the intended aim point neighbouring pairs are lit when the intended aim point is nearer to the point halfway between the pair than to an individual light (the companion light in the other "tramline" being treated equally in each case). Thus if the distance between successive lights is, say, 25 ft (7.6 m) as indicated in the Figure then a single light will be lit in each "tramline" if the intended aim point is within the distance of 12.5 ft (3.8 m) centered on that light or two lights will be lit in each "tramline" if the intended aim point is within that dis­tance centered on the mid point between those two lights. Simulator trials have also shown that this logic to indicate the position of the aim point can readily be assimilated.

1. A visual aid for the pilot of an aircraft approaching to land on a moving platform whereby in use a visual aim point is defined on the platform and the apparent position of such visual aim point along the platform is adjusted in response to excursions of the platform in the vertical sense so that registry of the visual aim point with an associated visual marker on or in the aircraft at any time indicates that the aircraft is on substantially the same specified glideslope fixed in space relative to the overall platform irrespective of such excursions thereof

2. An aid according to claim 1 comprising an array of lights distributed along the platform which are arranged to be lit selectively to indicate the position of such aim point at any time.

3. An aid according to claim 2 wherein said lights are arranged in a row or parallel rows along the platform and controlled such that the light in the or each row which is nearest to the intended aim point at any time is lit.

4. An aid according to claim 2 wherein said lights are arranged in a row or parallel rows along the platform and controlled such that a single light is lit in the or each row when the intended aim point is within a specified distance of that light and two successive lights are lit in the or each row when the intended aim point is within a specified distance of the mid point between those two lights.

5. An aid according to claim 2 wherein lights are also lit to indicate the effective limits of said array at any time.

6. An aid according to claim 2 wherein said array extends along a length of the platform such that different longitudinal sections thereof are capable of functioning to provide an adjustable aim point for a plurality of specified glideslopes fixed in space in different positions along the platform.

7. An aid according to claim 1 wherein said visual marker on or in the aircraft is presented in a head up display, helmet mounted display, or forward-looking camera display, or com­prises a physical marker on the aircraft structure, and repre­sents a depression angle from the horizon equal to the speci­fied glides lope angle.

8. An aid according to claim 1 for the pilot of an aircraft approaching to land on the deck of an aircraft carrier or the like vessel whereby in use a further visual indication is defined on the deck and the apparent position of such further visual indication is adjusted along the deck in response to excursions of the vessel in pitch so that when viewed along a specified sightline from the aircraft said further indication corresponds to the aftmost limit at which the aircraft will safely clear the stern of the vessel when following a specified glideslope parallel to said sightline irrespective of such excur­sions of the vessel.

9. A visual aid for the pilot of an aircraft approaching to land on the deck of an aircraft carrier or the like vessel whereby in use a visual indication is defined on the deck and apparent position of such visual indication is adjusted along the deck in response to excursions of the vessel in pitch so that when viewed along a specified sightline from the aircraft said indication corresponds to the aftmost limit at which the air­craft will safely clear the stern of the vessel when following a specified glideslope parallel to said sightline irrespective of such excursions of the vessel.

10. A method of approaching to land an aircraft on a mov­ing platform by use of a visual aid according to claim 1.

11. A method according to claim 10 wherein the aircraft is a V/STOL or STOVL aircraft executing a rolling vertical landing.

12. A method of approaching to land an aircraft on the deck of an aircraft carrier by use of a visual aid according to claim 9.

13. A method according to claim 12 wherein the aircraft is a V/STOL or STOVL aircraft executing a rolling vertical landing.
* * * * *

The Bedford Array is not in the Ford (CVN) design, but..........SRVL is intuitive to the Marines and the LHAs would be the likely platform to test, if not adopt the BA. I'm not opposed to the BA and I do see it as another "good?" Brit idea that is intuitive. The "Bee" will be flying onto the LHA and giving the pilots a tool with which to land on that "postage stamp" in addition to the "Land" button is fundamental. The "landing tools" information developed from the UCAV/ UCLASS programs will also be of great benefit ot the CATO and STOVL communities.

neptune, yes agree that the Bedford Array or similar is not in any USN carrier design at moment. Hence the USN LSOs thinking about such a thing to be retrospectively installed as appropriate. Perhaps reading all the bumpf above will help explain the USN LSO interest in light of the first post from the USN LSO newsletter. Marilyn Manson has a great song (expletives deleted) about "Are you MOFO ready for the newshit" . [ Chorus ONLY of 'This is the New SH_T' SONG] F-35 tech brings a lot of new stuff and leaves out a lot of old stuff - in the case of the F-35C the HUD is replaced by the HMDS along with the AoA Indexer I presume (will be in the HMDS). WHAT TO DO?!

Do new stuff.