Aviation Systems

8/11/2019 Aviation Systems

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AVIATION WEATHER

SURVEILLLANCE SYSTEMSAdvanced radar and surface sensors

for flight safety and air traffic management

PRAVAS MAHAPATRA

with contributions from

Richard J. Doviak

Vladislav Mazur

Dusan S. Zrnic

of the US National Severe Storms Laboratory

The Institution of Electrical Engineers

The American Institute of Aeronautics and Astronautics


2/13

Copublished by:

The Institution of Electrical Engineers,

Michael Faraday House,

Six Hills Way, Stevenage,

Herts. SG1 2AY, United Kingdom

and

The American Institute of Aeronautics and Astronautics

1801 Alexander Bell Drive

Suite 5

Reston

VA 20191-4344

USA

1999: The Institution of Electrical Engineers

This publication is copyright under the Berne Convention and the

Universal Copyright Convention. All rights reserved. Apart from any fair

dealing for the purposes of research or private study, or criticism or

review, as permitted under the Copyright, Designs and Patents Act, 1988

r

this publication may be reproduced, stored or transmitted, in any forms

or by any means, only with the prior permission in writing of the Institution

of Electrical Engineers IEE) or in the case of reprographic reproduction in

accordance with the terms of licences issued by the Copyright Licensing

Agency. Inquiries concerning reproduction outside those terms should be

sent to the IEE at the address above.

While the author and the publishers believe that the information and

guidance given in this work are correct, all parties must rely upon their

own skill and judgment when making use of them. Neither the author nor

the publishers assume any liability to anyone for any loss or damage

caused by any error or omission in the work, whether such error or

omission is the result of negligence or any other cause. Any and all such

liability is disclaimed.

The moral right of the author to be identified as author of this work has

been asserted by him/her in accordance with the Copyright, Designs and

Patents Act 1988.

ritish Library Cataloguing in Publication Data

A CIP catalogue record for this book

is available from the British Library

ISBN 85296 937 6

Printed in England by Short Run Press Ltd., Exeter


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to my p rents


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Preface

While writing this book I had the feeling of chasing and trying to catch the pieces

of an exploding bombshell. So rapid and diversified has been the growth of the

subject of this book in the recent past, that there was a distinct fear of the book

becoming obsolete even before it was completed. I have therefore taken the

approach of focusing more on the fundamental aspects of the aviation weather

problem and generic solutions to them. Specific equipment and systems are

referred to essentially to illustrate the capabilities and potential of modern

aviation weather surveillance systems, as well as the problems encountered in

performing the surveillance function. The specific systems also serve to provide a

realistic flavour to the description. One casualty of such an essentially generic

approach has been the relative lack of reference to specific software and

algorithms th at perform many of the intelligent tasks described in this book . But

given the fluidity of the software scene which undergoes rapid and continual

upgrading, substantial coverage of specific software would be impractical for a

book of this natu re.

The boo k is written with scientists, engineer s, airline techno logy m anage rs, civil

aviation planners and other interested meteorological and aviation personnel in

mind. Most of the material presented here should be of value in the training

programmes of aviation operators including pilots and air traffic controllers.

The literature in the area of aviation weather surveillance is vast but scattered

am on g a wide variety of sources. This highly interd isciplinary area of activity draws

personnel and information from diverse scientific and technological fields which

are fundamentally different from one another, each with its own distinct

methodology, focus and even jar go n. T his book is the first attem pt to mak e a

synthesis of such scattered inform ation an d to presen t it to pe rso nn el with diverse

backgrounds in a coherent manner for independent and self-contained reading.

The information contained here is graduated in such a way that the serious

technically minded reader can apprise himself or herself of many details of

modern aviation weather surveillance, while the lay reader can still get a fair

appreciation of the intricacies of the interplay of various apparently unrelated

factors in the common task of aviation quality improvement.

Pravas R. Mahapatra


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Acknowledgments

I am indebted to many in bringing this book to the present form. First and

foremost, I wish to express my deepest gratitude to Drs Dusan Z rnic and Dick

Doviak of the US National Severe Storms Laboratory (NSSL), who have long

been my friends, philosophers and guides in this area of inquiry, and who,

along with their colleague and my friend Dr Vlad Mazur, have contributed the

last three guest chapters of the book, and also othe r graphical material tha t

has greatly enriched this work. I have also been fortunate in receiving

inspiration, both philosophical and practical, from my special friend and

former director of NSSL, Dr Ed Kessler. A large number of professional

colleagues and manufacturers representatives from around the world have

generously contributed and permitted their material to be included in

this book, for which I am indebted to them. Input from my colleague

Prof. S. P. Govindaraju on aeroplane flight parameters appearing in

Chapter 2 is gratefully acknowledged. Also greatly appreciated is the he lp on

multiple occasions rendered by my long-time friend and colleague Dr M.

Sachidananda in obtaining hard-to-get reference material. Special thanks are

due to the editorial team at the IEE, especially Jo hn St Aubyn, Jo na than

Simpson and Fiona MacDonald who have provided superlative support on all

aspects connected with the processing of the manuscript. I am grateful to the

reviewers of the manuscript who have read the book with meticulous care and

made corrections and useful suggestions which have improved the quality of

the work. Finally, but importantly, I must express words of sentimental

gratitude to my wife Purn ima and children Satya and Pooja who have no t only

cheerfully borne the deprivation of my attention during the thick of this

project, bu t even cheered me u p during my long nocturnal writing sessions.


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Abbreviations

ACARS ARINC co m m un icatio n an d retrieval system

ACAS air bo rn e collision avo idanc e system

A / D analogue-to-digital (conv erter)

ADAS AWOS da ta acqu isition system

ADF auto m atic direction finder

AGC autom atic gain con trol

AGFS aviation gr idd ed forecast system

AJV aviation im pa ct variable

ARINC Aero naut ical Radio, Inc.

ARSR air rou te surveil lance rad ar

ART CC air ro u te traffic co ntro l ce nt re

ARTS auto m ated rada r term inal system

ASD aircraft situa tion display

ASDE airpo rt surface detect ion eq uip m en t

ASOS au tom ate d surface observ ing system

ASR airp ort surveil lance rad ar

ATC air traffic co nt ro l

ATCRBS air traffic co ntr ol ra da r be ac on system

ATM air traffic m an ag em en t

ATMS advan ced traffic m an ag em en t system

AV a irp o rt visibility

AWOS au tom ate d w eather observa tion system

AWPG aviation we ather pro duc ts ge ner ator

CAA Civil Aviation A uth ority (UK)

DME distance measu r ing equ ipm ent

EFAS en ro u te flight advisory service

FAA Fe der al Aviation A dm inistra tion (USA)

FAR Fe der al Aviation R egu lation (USA)

FAST fore/af t scanning techn ique

FDP flight da ta proc essing (or proc esso r)

FFT fast-Fourier transfo rm

GOES geostat ionary ope rat ional env ironm ental satell ite

GPS global po sition ing system

HF high frequency

ICAO In tern atio na l Civil Aviation Org anisation

IFR ins tru m en t f light rules


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ILS in str um en t land ing system

INMARSAT inte rna tion al m ari t im e satel li te organ isat ion

ITWR inter im termin al do pp ler rada r

ITWS integ rated term inal w eathe r system

JAWS jo in t airp ort we ather s tudies

K-H Kelvin-Helmhol tz

LAPS local analysis an d pr ed ic tio n system

LDR linear depo larisat ion rat io

LLWAS low level w ind sh ea r ale rt system

LLWAS-NE low level w ind sh ea r ale rt system with ne tw ork e xp an sio n

LOR AN long -rang e navigation system

LST local sta nd ard time

MAP meso scale analysis an d pre dic tio n (system)

MKS metre-kilogram-second

MLS microwave lan din g system

MO PA m aster oscillator pow er amp lifier

MST m esosph eric-stratospheric-tropo spheric (radar)

MVD m ed ian volum e dia m eter (of a po pu lat io n of drop lets)

NACA Na tional Advisory Co m m ittee on Ae ronau tics (USA)

NASA Na tional Ae ronau tics an d Space Ad m inistrat ion (USA)

NAWPG nation al aviation w eathe r pro du cts ge ne rato r

NCAR Na tional C ent er for Atm osph eric Research

NDB nondi rec t iona l beacon

NEXRAD nex t-gene rat ion rad ar (fo reru nn er of WSR-88D)

NIM ROD N or the rn I ll inois Meteorological Research on Dow nburs ts

PAR precision ap pro ac h rad ar

Pirep pi lo t rep or t

PO SH proba bility of severe hail

PPI plan-posit ion indic ator

PRF pulse repe ti t ion frequency

PRI pulse rep etitio n interva l (same as PRT)

PRT pulse rep etitio n time (same as PRI)

PU P principa l user processo r

RAMS regiona l atm osp heric m ode ll ing system

RASS radio-acoustic so un di ng system

RAWPG region al aviat ion we ather pro du cts ge ne rato r

RDA ra da r da ta acqu isition (un it or subsystem)

RDASC rad ar da ta acquisition status co ntro l

RDP rad ar data processo r (or processing)

RHI range-height indicator

RPG radar p rod uc t gene ra tor

RVR runwav visual ran ge

RWP real- t ime we ather processo r

SAV state-of-th e-atm osph ere variab le

SSR seco nda ry surveil lance rad ar

ST s t ra tospher ic- t ropospher ic ( rada r /prof i le r )

STC sensitivity-time co nt ro l

STO L sho rt takeoff an d land ing

TACAN tactical air nav igation (system)


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TASS ter m in al are a surv eillance system

TCA S traffic ale rt collision avo ida nce system

TDWR terminal dop pler weather radar

TO A time of arrival

TRACO N terminal radar cont ro l

TRSB t ime reference scanning beam

TVAD tan ge ntia l velocity azim uth display

TVS tor na do vortex s ignature

U H F ul t ra-high frequency

USAF U nite d States Air Force

V /ST O L ver t ica l / sho r t takeoff and landing

VAD velocity az im uth display

VFR visual flight ru les

VH F very high frequency

VLF very low frequ ency

VOR very-high-frequency om nira ng e

VORTAC coloc ated VO R an d TACAN systems

WISP win ter icing an d storm s projec t

WS R-88D wea ther surveil lance rada r - 1988 D opp ler


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ym ols

a, b constan ts used tospecify Z-R r e l a t ionship

c s peedofl ight

d

d i a m e t e r (ofhai lsto nes ); distanc e from sensor; thicknes sof

sheared layer

d

m ax

maximum distanceofradarforobserving weatherat a

minimum height

h

min

e

base

of

natural logarithm

e

m a x

h ig hes t e levat ion ang leofther a d a r a n t e n n a d u r i n gthe

scan cycle

f

c

c a r r i e r f requency

f

d

D o p p l e r f r eq u ency

f

dm

m ea n D o p p l e r f r eq u ency

(of an

e n s e m b l eofsca t terers)

f

r

pu l se repe t i t ion f requency

^v Nyquis t f requ ency

/

4

( 0 , ) no rm al is ed two-way pow er pa t te rnofa n t e n n a

g

a cce le ra t ionduetogravity

h

he ig ht (c l earance)

of

r ada r beam above g ro un d

(for

st raight - l ine propagat ion)

h height (c learance)ofr ada r bea m above g ro un d

(considering atmospheric refract ion)

h

m i n

minimum heightofobservationofweather phenomena

V T

k /?'/R(~4/3)

k

m

s a m p le n u m b e r (inf requency dom ai n ) co r res pon d i ngto

the mean Doppler f requency

l

c

referen ce length ( leng thofw ing cho rdatdes igna ted cross-

sect ion)

m refractive in de xofwater

n refractive in de xofair

n

r

t ot al nu m be rofresolut ion volum esorpixelsin afull circ le

of scan

r ran ge (dis tance)

to a

g iven resolut ion volum e

r pos i t ion vector

r

a a

radiusofairport area

r

b

maximum radiusofblind zone

r

m

maximum range (e.g.ofradar)


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r

m a x { a a

maximum permitted distance of radar from centre of

airport area (while providing resolution p

aa

over the

entire airport area)

r

m a x t a maximum permitted distance of radar from centre of

terminal area (while providing resolution p

ta

over the

entire terminal area)

r

m a x

P

maximum permitted distance of radar from the common

centre of airport and terminal areas while meeting the

resolution requirement everywhere within terminal area

r

ta

radius of terminal area

r

u

(maximum) unambiguous range

s

h h

complex scattering coefficient of a hydrometeor

considering the horizontally polarised component of

scattered radiation caused by a horizontally polarised

incident radiation

s

h v


considering the horizontally polarised component of

scattered radiation caused by a vertially polarised

incident radiation

s

v v


considering the vertically polarised component of

scattered radiation caused by a vertically polarised

incident radiation

t

two-way propagation delay corresponding to-a given radar

target or resolution volume

t

m

electromagnetic propagation time delay (two-way)

corresponding to maximum range

r

m

t

s

sampling instant

u, v, w orthogonal wind components wbeing vertical)

v wind vector

v horizontal wind speed

\

h

horizontal wind velocity vector

V

1

longitudinal velocity component

v

t

transverse velocity component

v

r

radial component of scatterer velocity relative to radar

V

77n

mean radial velocity (of an ensemble of scatterers) (used as

fin Chap. 11)

v

u

( m a x i m u m ) u n a m b i g u o u s v elo ci ty

w w e i g h t

of

a i r c ra f t

W

1

terminal velocity (of raindrops)

X

1

samples of (complex) receiver voltage output

B

receiver bandwidth

C radar constant

C

D

drag coefficient

C

L

lift coefficient

^ L m a x

maximum lift coefficient

C

M p

pitching moment coefficient

C\ turbulent structure parameter of refractive index

D drag force; diameter of raindrop


11/13

F

F-factor (related

to

wind shear)

F

equivalent average F-factor

/'(K) Fourier transform

of

weighting function

I

n

G

antenna gain

H

m ax

m a x i m u m a l t it u d eofw e a t h e r s u r v e i ll a n c e

H

D R

ha i l de tec t io n s ignal

/

i n- ph a se c o m p o n e n t

of

r a da r s ignal

I

n

a

n o r m a l i s e d w e i g h t i n g f u n c t i o n

K a t t en ua t ion coef fi c ien t

in

d B / k m ; m a g n i tu d e

of K

K w a v e n u m b e r

K

g

gus t al leviat ion factor

K

5

a t t e n u a t i o n c o e ff i ci e nt due

to

s now

K

1 0

c o n s t a n t r e l a t e dtor e f rac t ive in de xofw a t e r

K

D

p

specific differe ntial ph as e shif t

L lif t force; lo ga ri th mofr a t ioofe c h o p o w e rands ingle- lag

au t oco r re l a t i on es t imate ; l en g th (d i s t ance) in te rva l

L

a

a m p li tu d e loss factor (one-way)

Lf

rece iver f i l ter ing loss

(or

f ini te ba nd w id th loss) factor

L

5

system loss fac tor

M

n u m b e r

of

r ad a r pu l ses used

for

s igna l p roce s s ing (D op p le r

m o m e n t e s t i m a t i o n )

M p p i tc h in g m o m e n t

N n u m b e rofr a i n d r o p sperun i t spa tia l vo lum eperu n i t

d iame te r in te rva l ; no i se power

N

d

n u m b e r

of

ha i l s tones

per

cub ic m e t re

of

spa tia l volu m e

per

mill imetre s ize interval

P ins tan tan eo us pow er leve lofmic rowave rad ia t ion th ro ug h

air

P

0

initial po w er level

of

mic rowave rad ia t ion th ro ug h

air

P

a

ave rage t r ansm i t ted pow er

P

1

po we r associated withtheiths ignal sa m ple

P

r

r ece ived pow er (byr a da r )

P

ro

r e c e i v er o u t p u t p o w e r

P

t

t r ansm i t ted pow er (peak)

P e s t ima ted rad a r ech o pow er

Q q u a d r a tu r e c o m p o n e n tofr ad ar s ignal

R

r a d iusof theea r th; ra infa l l ra te ; auto co rre l a t io nof the

s igna l sample sequence

R' f ictit ious rad iu s

of the

e a r t h

to

a c c o u n t

for

a t m o s p h e r i c

refract ion

of

r a da r be a m

R

g

R i c h a rd s o n n u m b e r

R

s

rate

of

snowfall

S

r e f e re nce a re a (w ing p la t fo rm a rea )

S

k

th s a m p l e

of

thep e r i o d o g r a m

S

m

receiver sensitivity (minimum detectable signal)

S

xx

etc.

wind shear components

T a i rc raft en gi ne thr us t

T

x

pu l se r epe t i t ion t ime(orpulse repe t i t io n inte rva l )

T

1

temperature

of the

layer

in

which

a

wave evolves


12/13

U

de

derived gust velocity

V

9

V

6

radar resolution volume (the subscropt 6 explicitly denotes

6-dB thresholding)

V

a

airspeed of aircraft

Y

n

airspeed vector of aircraft

V

00

speed of aircraft relative to undisturbed air

W magnitude of the range weighting function (of processing

filter)

W absolute (inertial) wind vector

W

w

w i n d s p e e d p e r t u r b a t i o n due towe a th e r f ac to r s

W

x

h o r i z o n t a l w i n d c o m p o n e n t ( us ua ll y a l o n g a e r o p l a n e

g r o u n d t r a c k )

W

y

h o r i z o n t a l w i n d c o m p o n e n t p e r p e n d i c u l a r

to W

x

W

z

v er ti ca l c o m p o n e n tofw i nd (pos it ive d ow nw ards )

Z reflectivity fact or

Z

D P

reflectivity difference (between two different polarisations)

Z

D R

dif fere ntia l reflectivity

Z

e

eq uiv ale nt ref lect ivi ty facto r

Z

h

reflectivity fac toratho r izon ta l po la r i s a t ion

Z

v

reflectivity fac toratver t ica l pola r isa t i on

a angle of attack; constant inK-Rrelationship

a

s t a U

s tal l an gl e

of

a t tack

/3

p rof i ler be am t il t ang le ; co ns tan tinK-R r e l a t i o n s h i p

Sy Kronecker delta function (S =O,tef, S^=I, i=j)

s

extinction coefficient (or specific attenuation); normalised

turbulent energy dissipation rate

ref lect ivi ty

6

b

beam width

6 antenna scan rate

6

potential temperature

A wavelength (of radar signal)

p vector separation between two points (in the atmosphere)

P

0 0

dens i tyofu n d i s t u r b e dair

p

a

dens i ty

of

a m b i e n t

air

p

a a

l inear resolut ion req uir em en t over a i rpo r t area

p

d

duty ratio

p

hv

(0)

co r r e la t i on coeff i c ien t ofpo la r ised s ignalatz e r olag

p

s n

s ignal- to-noise rat i o

p

ta

l inear resolut ion req uir em en t overthe t e rminal area

(outsidethea i rpo r t area)

a

b

bac ksc atterin g cross section

of

ra in d ro p

T J

spectrum width component due to fall speed differences

among hydrometeors

J

0

s pec t rum width com pon en tdue too scillation (s)of

hydrome teo r s

av spec t rum width com po nen t

due to

ro ta t ion (scanning)

of

radar beam

c r

s

spectrum width component due to wind shear

T

1

spectrum width component due to turbulence


13/13

a

v

spectrum width of radial (Doppler) velocity (for an

ensemble of scatterers)

I

2

Q

second central moment of two-way antenna power pattern

a

2

r

second central moment of two-way range weighting function

c r

2

p

variance of the velocity at a point

T

radar pulse width

c f

h h

two-way phase shift with horizontally polarised transmission

and reception

(f)^ two-way phase shift with vertically polarised transmission

and reception

< f i

D P

differential phase (between two different polarisations)

kh

change in aircraft altitude

An turbulence-induced incremental vertical acceleration of

aircraft; perturbation in refractive index of air due to

turbulence

Ar range resolution

AiV number

of

r a indrops

per

un it spatial volum e having

diam eter be tweenD

and

D

+ AZ)

Ay difference

in

wind spe ed

(e.g.

across g ust fronts

and

microbursts)

A Fo urier wavelength

(i.e.

scale

of the

velocity pe r turb at io n)

I spectral density (tensor)

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