Rockwell Collins Rdr

Rockwell Collins WXR-2100MultiScan™ Weather Radar

Automatic operation

Accurate, clutter-free weather display

True 320 n.m. strategic weather

Geographic weather correlation

Path attenuation compensation

Four years operational experience

Presented by

Rockwell Collins

Cedar Rapids, Iowa

September 2007

Rockwell Collins WXR-2100 MultiScan™ Weather Radar .................................................................................................................................. 1

Core Technologies Enable Superior Performance and Capabilities ............................................................................................................... 4

MultiScan Digital Technology .................................................................................................................................................................................... 5

WXR-2100 MultiScan Weather Radar Operational Capabilities ..................................................................................................................11

Comprehensive Weather Analysis ..........................................................................................................................................................................16

Conclusion ....................................................................................................................................................................................................................18

Table of Contents

Rockwell Collins WxR-2100 MultiScan™ Hazard Detection Weather Radar System

1Rockwell Collins WxR-2100 MultiScan™ Weather Radar – September 2007© Copyright 2007 Rockwell Collins Inc.

MultiScanGCS ON150 Watt28" Antenna

NEXRAD250,000 Watt30 ft Antenna

Introduction/Executive SummaryThe Rockwell Collins WXR-2100 MultiScan™ Hazard

Detection Weather Radar System is a revolutionary

approach to the way weather information is processed,

refined and displayed. MultiScan Hazard Detection

Weather Radar System is an automatic weather sensor

that displays not just the classic precipitation rates,

but also significant weather hazards without pilot

manipulation of tilt or gain settings – all on a display

essentially devoid of ground clutter.

Few natural phenomenon possess weather’s disruptive

potential, and from the beginning, weather has had

an inexorable effect on aviation. Airborne weather

radar is one way of mitigating that effect and has long

been recognized by pilots and airlines for its safety

and operational benefits. Because of this potential,

weather radar has evolved from its early days as novel

new technology to the foundation for an integrated

surveillance suite of avionics; a source of flight critical

information. Early analog weather radars and the

associated monochromatic displays were able to provide

Rockwell Collins WxR-2100 MultiScan Hazard Detection Weather Radar System– continued


the pilot with generalized information on the location of

rain and convective weather. They had little capability to

display information about the severity of a storm, almost

no capacity to distinguish between various rainfall rates

and no potential to detect critical weather hazards. With

the electronic revolution came digital radars with color

displays. Digital electronics enabled the radar to acquire

a more accurate picture of the prevailing weather and

the color screens allowed for more descriptive cockpit

displays. Pilots could easily distinguish heavy rain from

light, and by observing the display’s color gradient, make

an educated judgment on the severity of convective

weather. As pilots developed increased confidence in

the information provided by these digital radars, they

were able to make more informed decisions concerning

deviations around or through weather systems. This

enhanced both safety and operational efficiency.

Later, the ability to detect and display windshear and

turbulence information was made available to the flight

crews. This development allowed the pilots access to

real-time data on two of the most significant and critical

aviation weather-related phenomena. Even with these

advancements there was still one important aspect of

weather detection missing from the cockpit; the ability to

look at the nature of a weather cell and identify or predict

the hazard it presented to the aircraft. It is now possible

to analyze a weather cell and gauge its convective

nature, intensity and maturity, detect turbulence and the

potential to produce hazardous lightning and hail.

Through research and listening to the desires of pilots

from all facets of the aviation community, Rockwell

Collins has continued to evolve its weather radar

products. This effort to advance radar technology resulted

in the most significant advancement in airborne weather

radar in the last 20 years. In 2002, the next generation

weather radar system known as the WXR-2100 MultiScan

Automatic Weather Radar was created. Numerous

patents have been awarded or are pending because of

the development effort behind MultiScan. Aviation Week

and Space Technology awarded its Technology Product

Breakthrough award to the radar in 2004 and one of its

inventors received the prestigious AEEC Volare award in

2005 for his efforts. In 2007 Flight International Magazine

named MultiScan its best product in the Propulsion,

Systems and Avionics category. In addition, NASA selected

Rockwell Collins as part of a team including Delta Air

Lines and AIR Research to develop and validate advanced

turbulence detection algorithms.

MultiScan broke new ground as the first, commercially

available, automatic weather radar. This automation

concept, facilitated by the algorithms contained

in MultiScan Automatic Weather Radar System,

revolutionized the way pilots utilize weather radar. By

automating many of the tasks previously performed by

the pilots, tilt and gain management for example, the

system reduces flight deck workload and allows pilots

to concentrate on weather avoidance instead of radar

operation and display interpretation. MultiScan enhances

weather detection accuracy at all altitudes and extends

the usable range of the radar to 320 nautical miles. It

virtually eliminates ground returns which relieves pilots

from the task of trying to differentiate weather returns

from ground clutter. OverFlight™ Protection reduced

the possibility of a MultiScan weather radar equipped

aircraft from inadvertently penetrating a non-reflective

thunderstorm top and Geographical Weather Correlation

optimizes radar performance based on location and

environmental conditions. Other algorithms provide for

the display of areas of potential turbulence while Path

Attenuation Correlation warns pilots of possible signal

attenuation. Pilots praise the radar’s capability to provide

accurate weather detection regardless of the airplane’s

location. Also, for the first time, MultiScan weather

radar allows the two pilots simultaneous, independent

control of operating mode, range and gain. This flexibility

enables the flight crew to display both the tactical and

strategic weather situation concurrently. With MultiScan

operating in automatic mode, all pilots have access

to weather information that previously was available

only to the most seasoned pilots with years of radar

3

Rockwell Collins WxR-2100 MultiScan Hazard Detection Weather Radar System– continued

Rockwell Collins WxR-2100 MultiScan™ Weather Radar – September 2007© Copyright 2007 Rockwell Collins Inc.

operating experience. These capabilities allow airlines to

standardized operating procedures and simplify aircrew

radar training. Since late 2002 when the WXR-2100

MultiScan radar was certified and entered service, more

than 105 airlines have placed over 3000 units in service

or on order. It is certified on the majority of the Airbus

line, all models of Boeing aircraft and is the only weather

radar offered on the Boeing 787 Dreamliner and the

Boeing Business Jet.

When MultiScan was introduced it set a new benchmark

for modern weather radars. It pioneered new

technologies and concepts into airborne weather radars

that began to take into account the actual characteristics

of a thunderstorm cell to improve weather detection

capabilities. As with any new scientific concept continued

research refines the initial findings. The same was true

for MultiScan. The result of over five years worth of

pilot operational input combined with a continuous

and aggressive research and development program,

the engineers at Rockwell Collins have created the next

significant evolution to the MultiScan product line; the

MultiScan Hazard Detection Weather Radar System.

This radar is as dramatic an improvement to the field

of weather radar as the original MultiScan. It is now

possible to not only detect the location and precipitation

levels of but provide pilots crucial information on

the actual hazards posed by the weather. Through

technologies such as Directed Sequential Hazard

Assessment, cell tracking and vertical weather analysis,

MultiScan now has the capability to provide information

never before available from airborne weather radar.

Pilots can know the height of individual weather cells,

whether a cell is growing, stable or decaying and the

potential for a cell to contain lightning and hail all

reference to the flight path of the aircraft. It is also

possible for the radar to display the vertical profile of

the weather to pilots on aircraft equipped with the

appropriate displays. MultiScan Hazard Detection also

benefits from expanded and enhanced geographic

weather modeling and adaptive radar controls. It is a

well-known fact that the nature of weather varies around

the globe. For example, the reflectivity characteristics of

thunderstorms differ significantly depending on whether

they are located in central United States, the South

Pacific and over equatorial Africa or other regions of the

world. For an automatic radar to provide a consistently

accurate weather presentation it must account for

these worldwide weather variations. If it does not it is

entirely probable that weather significant to the flight

path of the aircraft’s will go undetected. To ensure that

the weather models incorporated in the MultiScan

algorithms account for these weather variations and

provide pilots with reliable weather information Rockwell

Collins engineers documented the performance of the

radar in various parts of the world accumulating over

140 hours of flight data. The information collected in

this endeavor validated the various worldwide weather

types and ensured that the radar will detect significant

weather regardless of location and reflectivity. It will

also be used to further weather research in both the

commercial and academic arenas.

With the MultiScan Hazard Detection System pilots can

now traverse the globe with confidence knowing that

they have the most comprehensive airborne weather

information available. By depicting not only the weather’s

position but its associated hazards, MultiScan allows

pilots to make better, more informed, diversion decisions

thus improving passenger and crew safety, comfort and

operating efficiency.

Core Technologies Enable Superior Performance and Capabilities


MultiScan’s industry leading weather detection and

analysis capabilities are the result of an extensive suite

of newly invented core technologies that form the

foundation for its automated functionally and superior

performance. While the list of new technologies is

extensive, the most significant include MultiScan Digital

Technologies, Geographic Weather Correlation, Ground

Clutter Suppression, True Zero™ Automatic Antenna

Misalignment Compensation, SmartScan™ Rapid Update

Technology and Comprehensive Weather Analysis.

Together, these patented technologies provide the best

weather and hazard detection capabilities in the industry,

while at the same time, significantly reducing pilot work

load, increasing operating efficiency and better protecting

both passengers and crew from unexpected turbulence.

A highly effective, fully automatic radar can only exist

if it contains these technologies developed by Rockwell

Collins. Three years of development and more than five

years of in-service maturation have proven their critical

nature.

MultiScan has been selected as the sole source radar for both the Boeing Business Jet and the 787 Dream Liner.

5

Ideal Radar Beam EmulationThe ideal radar beam is not achievable within the laws of

physics. If it was, it would be able to look directly below

the aircraft and then follow the curvature of the earth

out to the radar’s maximum range. These characteristics

would allow that ideal beam to detect any and all

significant weather and thunderstorms from the nose

of the aircraft out to the theoretical maximum range. In

addition, the ideal radar would also ignore ground clutter

and would maintain a consistent signal level throughout

its range. It wouldn’t lose energy over time and distance

nor would extremely heavy precipitation attenuate the

signal.

The MultiScan Process The truth of the matter is that while the ideal radar

beam does not exist except in theory, MultiScan’s use of

advanced digital technologies, comes very close to it. The

radar uses multiple radar scans at different tilt angles to

detect the prevailing weather and store the information

into computer memory. The patented Rockwell Collins

algorithms process this raw radar information, using

advanced digital technology, and the complete weather

picture, less ground clutter, is displayed to the pilots

based on their preferences as selected on their individual

control panels. The result is the ability for flight crews to

view all significant weather from directly in front of the

aircraft to 320 n.m., essentially free of ground clutter. This

entire process occurs automatically and is completely

transparent allowing the flight crew to concentrate

on weather avoidance rather than weather radar

manipulation and display interpretation.

Digital signal processing also allows the radar to vary

numerous operating parameters based on atmospheric

temperature profiles, seasonal variations and geographic

location. This enables the radar to maintain a consistent

level of performance regardless of location providing

the optimum display of the prevailing weather in the

worldwide operating environment typical of today’s

operations.

MultiScan Digital Technology


Ideal radar beam (note earth’s curvature causes a drop of approximately 65,000’ over a distance of 320 n.m.).

MultiScan emulation of ideal beam.

The MultiScan process.

MultiScan Ground Clutter Suppression (Patented)A key factor that distinguishes MultiScan Hazard

Detection Weather Radar System from other radars is

the radar’s capability to separate weather returns from

ground returns or ground clutter. By automatically

providing flight crews with an essentially ground-clutter

free display MultiScan eliminates the need for pilots to

distinguish between clutter and weather returns.

The first picture below shows a radar display typical of

today’s manual systems. Weather returns are mixed with

ground returns making the weather, except that very

close to the aircraft, almost indistinguishable. The second

picture shows the same weather presentation during

MultiScan Hazard Detection Weather Radar System

automatic operation. As is illustrated the MultiScan

ground clutter suppression techniques clearly enable

the display of weather that was previously hidden in the

ground returns

MultiScan Digital Technology – continued


MultiScan is able to look down into ground clutter to detect the reflective portion of thunderstorms. The picture above shows the radar picture with the ground clutter suppression turned off. Weather is masked by the ground clutter.

When Ground Clutter Suppression (GCS) is activated, all significant weather (in this case from right in front of the aircraft out to 160 n.m.) is visible on a single, essentially clutter free, display.

In geographic regions where thunderstorms exhibit high

reflectivity characteristics, the radar normally must look

below the 25,000-foot level in order to see and display

the cell. In geographic regions where thunderstorms are

characterized by low reflectivity levels, such as Pacific

Ocean storms, the radar must look even lower in the cell

in order to properly display threat weather. The following

figures demonstrate the challenges faced by manual

radar. Since highly reflective targets such as ground and

cities reflect a greater portion of the energy back to the

radar antenna, the edge of the beam must be above the

ground in order to avoid these highly reflectivity targets.

This causes the center of the beam, the part used for

weather detection, to be well above the reflective part

of the thunderstorms. Previously, pilots had to manually

manipulate gain, tilt and range to in an attempt to

separate ground returns from actual weather. The

patented MultiScan ground clutter suppression (GCS)

algorithms replace these manual pilot inputs allowing

the radar to display weather returns that were normally

hidden by ground clutter. By allowing the radar to

operate at lower tilt angles looking down into the most

reflective portion of the storm, without displaying ground

clutter, pilots now have better information on which

to base their deviation decisions. To better understand

the fundamentals behind Rockwell Collins’ GCS, a short

explanation of thunderstorm reflectivity, radar beam

characteristics and radar beam tilt control is in order.

7

Thunderstorm Reflectivity ProfileA thunderstorm’s reflectivity profile provides

the design criteria for MultiScan Ground

Clutter Suppression Technology. In general,

thunderstorm reflectivity can be divided into

three parts lower, middle and top. The bottom

part of the storm below the freezing level is

composed entirely of water and is the portion

that most efficiently reflects radar energy.

The middle of the storm is composed of a

combination of super cooled water and ice

crystals. Reflectivity in this part of the storm

begins to diminish due to the fact that ice

crystals are very poor radar reflectors when

compared to rain. The top portion of the storm

is composed entirely of ice crystals and is

almost invisible to radar. In addition, a growing

thunderstorm will have a turbulence bow

wave above the visible portion of the storm.



Thunderstorm reflectivity levels.

Best Weather Returns

Compromise Tilt Setting

Best Ground Clutter Rejection

8

Radar Beam CharacteristicsTo detect a relatively weak target such as weather air

transport aircraft, flat plate antennas produce a beam

that is approximately 3.5-degrees wide and is essentially

circular in cross section. However, the 3.5-degree beam

width describes only the center, most powerful portion

of the radar beam. Medium reflectivity targets such as

farmland and strong targets such as urban build-up can

be detected much farther out on the perimeter of the

beam. In fact, the radar beam that can detect urban

targets is 8-degrees wide. At 200 n.m., this equates to a

diameter beam of approximately 170,000 feet. Manual

radars or radar systems that use data base clutter editing

techniques must raise the center of the beam 85,000

feet above the terrain at 200 n.m. to assure a clutter free

display (see figure 8).

When you combine the characteristics of a radar beam

with the reflectivity profile of the typical thunderstorm,

it is easy to understand why trying to find an appropriate

tilt angle that adequately displays weather and minimizes

ground clutter is difficult. The relatively low reflective

nature of a thunderstorm requires that the most

powerful, center portion of the radar beam be aimed into

the lower, highly reflective, part of the cell. This exposes

a significant amount of the periphery of the radar beam

to highly reflective terrestrial targets. As a result, the

reflected energy returned to the aircraft is a combination

of weather and ground returns. Manual radars require

flight crews to continually adjust the tilt angle and range

settings in an attempt to distinguish between ground

clutter and weather returns. It requires a great deal of

skill on the part of the pilot to operate the radar, decipher

what he is seeing and develop an accurate understanding

of the weather situation. MultiScan Hazard Detection

Weather Radar System automatic operation enables

all pilots, regardless of their experience level, to see a

realistic representation of the actual weather situation.



3.5° Beam Weak Targets (Weather)

6° Beam Medium Targets (Farmland)

8° Beam Very Strong Targets(Urban Clutter)

37,000 ft.63,500 ft.

85,000 ft.

Radar Beam Cross Section

Radar antenna beam characteristics at 200 n.m.

9

Geographic Weather Correlation (Patented)Thunderstorm threats vary dramatically depending

on the different geographic regions in which they are

formed. Recent meteorological research has shown that

thunderstorm reflectivity characteristics vary significantly

depending upon location and even time of year. Mid-

latitude land mass thunderstorms exhibit reflectivity

profiles that are quite different from equatorial land

mass storms which are different from equatorial oceanic

storms. For example, oceanic weather is, on average,

one thousand times less reflective than storms of

corresponding height that form over continental land

masses. Pilots flying aircraft equipped with manual

weather radar are required to learn different operating

techniques depending on what area of the world their

aircraft is operating in if they are to obtain an accurate

depiction of the weather. Algorithms developed by

Rockwell Collins and incorporated into MultiScan Hazard

Detection Weather Radar System automatically adjust

weather detection parameters based on regional storm

models to provide optimum weather returns at all times

regardless of location. MultiScan creates a tailored

solution to a multi-variable problem providing operators

consistency of performance regardless of the particular

route segment.

True Zero Automatic Antenna Misalignment Compensation (Patented) As airborne weather radars have become more

sophisticated, installation accuracy has become more

critical. Tilt errors that in the past were irrelevant to

the manual radar can form due to pedestal installation,

alignment errors, inertial platform errors and even

the fuselage bending moments that an airframe

experiences in flight. Tilt errors as small as 0.7 degrees,

not uncommon in today’s installations, will be significant

for an automatic radar. If these errors are not corrected

in real time, the end result is serious degradation of the

automatic scanning capabilities of the radar. The radar

beams will either be aimed too high or too low, resulting

in either detecting too much ground clutter or too little

weather. MultiScan incorporates patented True Zero

technology that automatically corrects for hidden tilt

errors, ensuring optimized system performance for all

aircraft types.



Non-optimized weather display of low reflectivity oceanic weather.

MultiScan optimized weather display of low reflectivity oceanic weather.

10

SmartScan Technology (Patented)During turns, the MultiScan Hazard Detection Weather

Radar System uses SmartScan technology to ensure

weather in the direction of the turn is displayed promptly

and accurately. When an aircraft turns, the scan rate of

current generation radars results in the loss of weather

information in the direction of the turn. This results in

a situation in which flight crews could be momentarily

blind to the weather towards which the aircraft is turning.

MultiScan solves this problem by using SmartScan to

adjust the radar scan in the direction of the turn, thus

ensuring quick revisit times. As a result, even though

MultiScan uses multiple scans to build a complete

weather picture, weather information that is falling off

the trailing edge of the display is “pasted in” from digital

memory to provide a complete weather picture.



The aircraft in this picture is turning right. SmartScan ensures rapid update rates by causing the radar to scan just in the direction of the turn. Weather falling off the display is "pasted" in from digital memory to provide a complete weather picture.

11

Rockwell Collins’ MultiScan automatic weather radar

is a revolutionary idea in radar technology supported

by an evolutionary process to provide our customers

with cutting edge performance. The basis for this

statement lies in the advanced technologies incorporated

in MultiScan. Its capabilities provide pilots access to

a comprehensive and accurate tactical and strategic

weather picture enabling them to take steps to avoid

weather hazards. Rockwell Collins has advanced airborne

weather radar from being just a rain gauge to a hazard

assessment tool.

Optimum Weather DetectionMultiScan provides to the pilots essentially all the

operational capabilities they could ask for in one package.

Traditionally weather radar is one part of the cockpit

avionics suite that requires a significant amount of hands

on experience to obtain proficiency. While an airline’s

training program teaches pilots the basic operations of

the weather radar, it is through actual flight experience

gained on those dark stormy nights that teach pilots

the operating and display interpolation techniques that

allow them to conduct flights safely in areas of significant

and convective weather. This is because the current

generation weather radar does nothing more than display

the information that is reflected from whatever targets

the radar beam strikes. This limitation means that the

quality of the information obtained is directly influenced

by the skill of the pilot operating the radar. Appropriate

range selection, along with astute manipulation of

the tilt and gain controls, was critical to obtaining

accurate information. Even then, the data obtained was

a compromise because of ground clutter interference,

signal attenuation or the characteristics of the particular

weather system. After dealing with these inherent system

limitations it was the pilot’s responsibility to correctly

interpret the information displayed on the screen; all this

in addition to performing the “routine” task of flying the

airplane.

WxR-2100 MultiScan Hazard Detection Weather Radar System Operational Capabilities


12

Automatic OperationTo address this situation, Rockwell Collins decided to

move weather radar operation from an experience-based

skill to a technologically based capability. The design

concept behind MultiScan was to create the industry’s

first automatic weather radar. The goal was to offer flight

crews, with the exception of range selection, hands-

free operation. In the automatic mode, the embedded

algorithms manage all aspects of radar operation. Tilt

angle, gain and all other functions of radar operation

occur without intervention by the pilots. All the pilot

has to do is selected the AUTO mode and all weather

significant to the aircraft from the nose out to 320 n.m.

is available. Pilots no longer have to manually vary tilt,

gain or even the mode in an attempt to assemble a

mental picture of the prevailing weather. They will only

have to take the appropriate operational decisions using

the weather information automatically provided by

the radar. Ground clutter is automatically eliminated,

allowing for an accurate depiction of weather by allowing

MultiScan to concentrate the radar energy in the lower,

most reflective, part of the storm. Gain is incrementally

increased as temperature decreases to more accurately

depict the dry upper levels of thunderstorms. This

series of pictures shows an approach towards a line of

thunderstorms over New Orleans. The only pilot input

required was range selection. Short, medium and long

range weather is displayed. These pictures represent

MultiScan today and dramatically demonstrate the

current in-service capabilities of the radar that are, as yet,

unmatched by any other radar system.

WxR-2100 MultiScan Hazard Detection Weather Radar System Operational Capabilities – continued


320 n.m. Range Scale. Line of cells at 240 n.m..




13

OverFlight Protection (Patented)At cruise altitudes, with tilt and gain adjusted to display

en route weather, it is not uncommon for current

generation radars to scan over the top of the reflective

portion of a thunderstorm while the low reflective top

portion of the storm still in the aircraft flight path goes

undetected. It is estimated that as much as 65 percent of

what is called clear air turbulence is, in fact, turbulence

associated with unintended over flight of a lower lever

storm. Figure A. OverFlight Protection provided by

MultiScan uses a combination of lower and upper beam

information, combined with stored data, to display the

low reflectivity thunderstorm tops that would disappear

from the screen of a normal range as range decreases

inside approximately 40 n.m. depending on the operating

altitude. The tops will be displayed until they pass behind

the aircraft. By continuing to display these storm tops,

MultiScan ensures that the pilot is aware of all significant

weather and potential turbulence that could affect his

aircraft and ultimately the passengers and crew.



As the aircraft approaches the non‑reflective top of the thunderstorm the reflective portion of the storm falls beneath the radar beam and the threat weather disappears from the display.

A. OverFlight Protection – low reflectivity oceanic storm top that would normally disappear from the radar display 40 n.m. from the aircraft remains in view until it passes behind the aircraft.

14

Path Attenuation and Correction (PAC) AlertSignal attenuation is another characteristic of a radar

beam that pilots must be aware of. It is applicable to all

radars. A basic principle of weather radar theory is that

rain reflects the radar energy back to the antenna so

that the signal can be received, process and displayed. It

stands to reason that in an area where rain is extremely

heavy, all the transmitted radar energy is either reflected

back to the aircraft or is absorbed by the precipitation.

Known as signal attenuation, weather beyond that point

remains undetected and is not displayed to the pilots.

This can create a dangerous situation since pilots see

what appears to be an area clear of weather on their

radar display and believe it is safe to transit, but in

fact, no information about the weather in that area is

available. Rockwell Collins’ unique PAC alert identifies

the attenuated area, sometimes called a radar shadow,

caused by the intervening rainfall by placing a yellow “PAC

Alert” bar on the outer most range scale. The alert warns

the flight crew that the displayed information could be

incomplete so they can plan their diversion accordingly.

Enhanced Turbulence DetectionTurbulence causes more injuries on commercial aircraft,

to both passengers and crew, than any other weather

phenomena. It is frequently associated with convective

weather but can be present in any weather system and

in many cases occurs without warning. Current advanced

weather radar systems, including MultiScan, can display

weather related turbulence within 40 n.m. of the aircraft.

In a 2004 head-to-head competition, Rockwell Collins

won the NASA contract to bring Enhanced Turbulence

(E-Turb) to market. Enhanced Turbulence detects very

low reflectivity turbulence and provides flight crews

warning of both light and moderate turbulence events.

Rockwell Collins is now leading both the research and

development work within the industry defining the E-Turb

requirements and is currently flight testing two-level

E-Turb software on a Delta 737 NG aircraft. Turbulence

will still be displayed on the radar but now at two

different intensity levels. Speckled magenta areas will

indicate mild turbulence and solid magenta areas indicate

regions of moderate to severe turbulence.



MultiScan displays a yellow "PAC Alert" bar to warn flight crews of areas of attenuation (radar shadow) where weather may not be displayed.

15

Windshear Detection and WarningWindshear has been determined to be the cause or

a contributing factor in numerous aircraft accidents.

To address this fact ,MultiScan automatically detects

the existence of windshear and provides appropriate

warnings to the pilots during take off and landing.

MultiScan further enhances the safety aspects of its

windshear warnings by continuing to display weather

behind the windshear icon, unlike competing radar

systems that cycle between a weather display and the

windshear warning with no weather.



WindshearIcon (marksactual wind-shear location)

Continuous WxBehind the Wind-shear icon

Yellow arc points to windshear (even onrange scales that might not display the actual wind-shear icon)

WindshearWarning

MultiScan windshear display.

40 n.m. range scale. 80 n.m. range scale. Turbulence displayed out to 40 n.m..

Turbulence

16

Through Rockwell Collins’ continual research and periodic

customer interchanges outlining future weather radar

requirements, MultiScan has continued to evolve.

The latest innovation incorporated into MultiScan is

a function known as Comprehensive Weather. This

functionally will provide storm top information, Predictive

OverFlight protection, enhanced turbulence analysis and

detection and evaluation of weather along the aircraft

flight path as programmed in the FMC.

Directed Sequential Hazard Assessment Technology (Patented)The foundation for Comprehensive Weather and all the

information derived from it is a capability known as

Directed Sequential Hazard Assessment. This technology

allows MultiScan to detect weather hazards and then,

using a combination of horizontal and vertical scans,

performs a threat analysis tailored to the phase of

flight. Directed Sequential Hazard Assessment allows

MultiScan to change radar parameters such as frequency,

wave length and pulse width to thoroughly evaluate the

specific weather and determine its threat potential. This

weather assessment intelligence transforms MultiScan

into a threat detector instead of just being a simple “rain

gauge” like other radars. The result is the capability to

provide flight crews information on storm height, growth

rate and turbulence potential all referenced to the aircraft

flight plan. The following provides more detail on these

features.

Comprehensive Weather Analysis


MultiScan Directed Sequential Hazard Assessment technology allows the radar to determine the actual thunderstorm threat, not just the amount of moisture in the air, during all phases of flight.

17

Predictive OverFlight ProtectionDeveloping thunderstorms can exhibit tremendous

growth rates rising rapidly into the aircraft flight path.

With other radar systems it is the responsibility of the

flight crew to identify these cells and plan their flight

path accordingly. Depending on the skill of the pilot,

these developing cells may not be depicted on the radar

display and often have an area of associated intense clear

air turbulence above the cells. MultiScan’s Predictive

OverFlight feature can analyze a cell’s growth rates and

make predictions on whether the storm or the clear air

turbulence “bubble” above the cell will reach the aircraft

flight level. Using this information, the radar will then

display to the flight crew those cells that present a future

turbulence or weather hazard.

Flight Phase Hazard AnalysisWeather at low altitude, during climbs and descents and

during cruise presents different threats to the aircraft.

Based on the flight plan information contained in the

aircraft FMS, MultiScan Hazard Detection Weather

Radar System Flight Phase Hazard Analysis will enable

the evaluation of the actual weather threat along the

aircraft’s flight path tailored to the phase of flight. Each

phase of flight uses radar techniques best adapted for the

weather detection and evaluation in that region in order

to display the actual threat.

Storm Top InformationKnowing the vertical extent of a weather cell can

be critical to a pilot’s diversion decision. Until the

development of the MultiScan Hazard Detection Weather

Radar System algorithms, there was no universally

accepted method of estimating the top of a weather

system. With MultiScan Hazard Detection Weather Radar

System storm top information will be displayed on the

navigation display. This information, when combined

with typical plan form radar display, will allow flight

crews to determine the best possible weather avoidance

maneuver; either laterally, vertically or a combination of

the two. Flight crews have all the information required to

determine the best route of flight.

Comprehensive Weather Analysis – continued


MultiScan Predictive OverFlight feature warns the flight crew of turbulence associated with thunderstorms that are growing into the aircraft flight path.

18

In just a few short years, MultiScan has redefined weather

radar technology and operation. Prior to MultiScan, the

effectiveness of airborne weather radar to accurately

display weather was directly dependent upon the skill

and experience of the pilot. Even with a skilled operator

using proven techniques, the information being displayed

was a compromise between weather and ground

returns and required a great deal of interpretation on

the part of the operator to decipher the actual weather

situation. MultiScan, using advanced algorithms such as

ground clutter suppression and digital signal processing,

automatically provides the flight crew with an accurate

depiction of their weather situation without the need

for the pilots to continually manipulate tilt angle, gain

and range controls. In addition, geographic weather

correlation, True Zero antenna alignment and SmartScan

technologies further enhance the accuracy of the

depicted weather data while path attenuation alerts,

turbulence displays and windshear detection and alerting

increase operational safety. Directed Sequential Hazard

Assessment with the ability to analyze weather based on

phase of flight and planned route will provide a complete

picture of the actual threat potential of a weather system.

These technologies, combined with the fully automatic

operation, define a new standard for the industry.

MultiScan Hazard Detection Weather Radar System

provides pilots with the capability to improve passenger

comfort, increase operational efficiency, and reduce pilot

workload while enhancing safety.

Conclusion


147-0118-001-CS 1M 09/07 © Copyright 2007, Rockwell Collins, Inc.All rights reserved. Printed in the USA.

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