+ All Categories
Home > Documents > 5. Session D "Meteorological Radars" Presentation 5.2.A: "Wind profiler radars"

5. Session D "Meteorological Radars" Presentation 5.2.A: "Wind profiler radars"

Date post: 01-Jan-2016
Category:
Upload: thomas-jordan
View: 31 times
Download: 6 times
Share this document with a friend
Description:
Workshop on Radiofrequencies for Meteorology. 5. Session D "Meteorological Radars" Presentation 5.2.A: "Wind profiler radars". by Hans Richner, chairman SG RFC IAC ETH , Zurich, Switzerland. What is as wind profiling radar?. 1.active remote sensing system, i.e., it emits radiofrequencies. - PowerPoint PPT Presentation
38
Hans Richner, IACETH, Zurich Workshop RF for Meteorology, October 7/8, 2002, Geneva 5. Session D "Meteorological Radars" Presentation 5.2.A: "Wind profiler radars" by Hans Richner, chairman SG RFC IACETH, Zurich, Switzerland Workshop on Radiofrequencies for Meteorology
Transcript

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

5. Session D "Meteorological Radars"Presentation 5.2.A:

"Wind profiler radars"

byHans Richner, chairman SG RFC

IACETH, Zurich, Switzerland

Workshop on Radiofrequencies for Meteorology

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

2. specialized Doppler radar system with elaborate data processing

What is as wind profiling radar?

1. active remote sensing system, i.e., it emits radiofrequencies

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

basic beam configuration of a wind profiler

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

horizontal motion can be decomposed into a radial and a perpendicular component

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

The CWINDE network in Europe

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

wind profilers come in many shapes an sizes!

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

10 m

100 m

1 km

10 km

100 km

50 km

20 km

5 km

2 km

500 m

200 m

20 m

50 m

50 MHz

400 MHz

1000 MHz

acousticsounders

balloons

tropopause

6 - 12 h

1 - 2 h

10 - 30 min.

10´ 10´ 10´ 10´ 6 havailable at

height

requiredevery

intervals

height ranges for the different frequencies

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

47 68 88108144172

223

401-406

470 MHz

960 MHz

TV (F-I)

FM (F-II)

TV (F-III)

AERO

METEO

TV (F-IV/V)

1215 MHz

AERO (RES.)

300 MHz

VHF

UHF

862 MHz

400 MHz

1000 MHz

rough representation of the different allocations in the frequency range 30 - 1300 MHz

50 MHzhere we have allocations for wind profilers!

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

1215 MHz

890 MHz

960 MHz

fixed andmobile services

aeronauticalradionavigation(DME)

radiolocation,radionavigation, andaeronauticalradionavigation

1350 MHz

(CB)

situation near 1000 MHz

915 MHz(region 2 only!)

1290 MHz

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

RESOLUTION COM5‑5 (WRC‑97)IMPLEMENTATION OF WIND PROFILER RADARS...

1 to urge administrations to implement wind profiler radars as radiolocation service systems in the following bands, having due regard to the potential for incompatibility with other services and assignments to stations in these services, thereby taking due account of the principle of geographical separation, in particular with regard to neighbouring countries, and keeping in mind the category of service of each of these services:

46 - 68 MHz in accordance with No. S5.162A440 - 450 MHz470 - 494 MHz in accordance with No. S5.291A904 - 928 MHz in Region 2 only1270 - 1 295 MHz1 300 - 1 375 MHz;

...

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

excerpt from Radio Regulations:

44

68

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

S5.162A Additional allocation: in Germany, Austria, Belgium, Bosnia and Herzegovina, China, Vatican, Denmark, Spain, Estonia, Finland, France, Ireland, Iceland Italy, Latvia, The Former Yugoslav Republic of Macedonia, Liechtenstein, Lithuania, Luxembourg, Moldova, Monaco, Norway, Netherlands, Poland, Portugal, Slovakia, the Czech Republic, the United Kingdom, Russia, Sweden, Switzerland and Turkey, the band 46 - 68 MHz is also allocated to the radiolocation service on a secondary basis. This use is limited to the operation of wind profiler radars in accordance with Resolution COM5-5 (WRC-97).

46 - 68 MHz is also allocated to the radio-location service on a secondary basis

use is limited to the operation of wind profiler radars

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

RESOLUTION COM5‑5 (WRC‑97)IMPLEMENTATION OF WIND PROFILER RADARS...

1 to urge administrations to implement wind profiler radars as radiolocation service systems in the following bands, having due regard to the potential for incompatibility with other services and assignments to stations in these services, thereby taking due account of the principle of geographical separation, in particular with regard to neighbouring countries, and keeping in mind the category of service of each of these services:

46 - 68 MHz in accordance with No. S5.162A440 - 450 MHz470 - 494 MHz in accordance with No. S5.291A904 - 928 MHz in Region 2 only1270 - 1 295 MHz1 300 - 1 375 MHz;

...

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

440-450

Radiolocation

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

S5.291A Additional allocation: in Germany, Austria, Denmark, Estonia, Finland, Liechtenstein, Norway, Netherlands, the Czech Republic and Switzerland, the band 470 - 494 MHz is also allocated to the radiolocation service on a secondary basis. This use is limited to the operation of wind profiler radars in accordance with Resolution COM5-5 (WRC-97).

470 - 494 MHz is also allocated to the radiolocation service on a secondary basis

use is limited to the operation of wind profiler radars

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

RESOLUTION COM5‑5 (WRC‑97)IMPLEMENTATION OF WIND PROFILER RADARS...

1 to urge administrations to implement wind profiler radars as radiolocation service systems in the following bands, having due regard to the potential for incompatibility with other services and assignments to stations in these services, thereby taking due account of the principle of geographical separation, in particular with regard to neighbouring countries, and keeping in mind the category of service of each of these services:

46 - 68 MHz in accordance with No. S5.162A440 - 450 MHz470 - 494 MHz in accordance with No. S5.291A904 - 928 MHz in Region 2 only1270 - 1 295 MHz1 300 - 1 375 MHz;

...

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

902-928

Radiolocation

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

707 In Region 2, the band 902 - 928 MHz (center frequency 915 MHz) is designated for industrial, scientific and medical (ISM) applications. Radiocommunication services operating within this band must accept harmful interference which may be caused by these applications. ISM equipment operating in this band is subject to provisions of No. 1815.

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

1270 - 1295RADIOLOCATION

CO-PRIMARY !!!

1300 - 1375

RADIOLOCATION

Radiolocation

CO-PRIMARY !!!RADIOLOCATION

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Summary of basic allocations for wind profilers:

50 MHz systems:46 - 68 MHz worldwide, case by case

400 MHz systems:470 - 494 MHz in Region 1 (Europe)440 - 450 MHz in Region 2 (Americas)

1000 MHz systems:1270 - 1295 MHz Region 1

915 MHz Region 2

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

EMC (electromagnetic compatibility) considerations

Basically two different problems:

(i) the profiler must be protected from receiving signals from other sources

(ii) the profiler must not emit signals that interfere with other communication (e.g. TV) or location (e.g. radar) systems.

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

passive measures

• siting • improving the antenna always

alleviates both problems

active measures

• increasing transmitter power• increasing receiver sensitivity

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

EMC problems are specific for profiler families

The most important potential interfering systems include: 50 MHz: band I television system (which, however, are

gradually phased out), communication systemsnearby power lines

400 MHz: band IV television systems1000 MHz: air route surveillance radars (ARSR)

space-borne SAR (?)Galileo (?)

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Wherever possible, a maximum frequency separation as well as a maximum distance separation should be sought.

rule of thumb

400 MHz profilers can operate within television channel, if distance separation is about 40 km from TV servicing area.Maximal side lobe suppression is an effective measure for preventing problems.

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

for alleviating any of the EMC problems, proper distance and/or frequency separation, an optimized orientation of the inclined beams, plus a very "clean" radiation pattern are the most effective means. The latter can be improved by either "artificial" (fence) or "natural" (depression) shielding.

summary

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Antenna radiation pattern of the vertical and an oblique beam of a 482 MHz wind profiler

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

the heartaches with pulsed systems….

time domainefrequency domaine

(spectrum)

continuous wave

modulated (here AM)

pulsed

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

0 dB

-20 dB

-10 dB

-30 dB

-40 dB

-50 db

-60 dB

necessarybandwidth

-3 dB

-3 dB bandwidth

occupied bandwidth

manufacturers and scientists have to get used to the fact that that they must not occupy excessive bandwidth!

first wind profilersratio 8 : 1

best wind profilers todayratio 1.5 : 1

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

RASS: Radio-Acoustic Sounding System

Bragg condition:ac = 2· em

cac = 20.05·sqrt(Tv)

cem

cac

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

The EndThe End

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Co-channel operation with ARSR has not been investigated; however, experiments were carried out where the spectrum of a 1260 MHz ARSR partially overlapped with that of a 1290 MHz profiler. A separation of 8 km proved to be sufficient to prevent the radar from interfering with the profiler. (Given the huge power of the ARSR, the problem of the profiler interfering with the radar is not an issue.)

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

The operators of Earth exploration satellites using synthetic aperture radar (SARs) repeatedly claimed to suffer from interference caused by wind profilers. However, there is no evidence -- neither experimental nor theoretic -- that a wind profiler ever interfered with a SAR system. It should be remembered that the power in the very narrow main beam of a profiler is about 20 dB less than the isotropically radiated power of an ARSR, and both are operated in the same frequency region.

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

Hans Richner, IACETH, Zurich

Workshop RF for Meteorology, October 7/8, 2002, Geneva

just a little theory:

f2f2

“classic” radar

t = time delay between signal sent and echo received; distance = F(t)

t = time delay between signal sent and echo received; distance = F(t)f = f1 - f2 = Doppler shift; radial velocity u = G(f)

uf1f1

Doppler radar


Recommended