Friday, April 26, 2013

Weather Surveillance Radar

Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation.

Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather.

During World War II, radar operators discovered that weather was causing echoes on their screen, masking potential enemy targets. Techniques were developed to filter them.

Raw images are routinely used and specialized software can take radar data to make short term forecasts of future positions and intensities of rain, snow, hail, and other weather phenomena. Radar output is even incorporated into numerical weather prediction models to improve analyses and forecasts.


http://en.wikipedia.org/wiki/Weather_surveillance_radar


 

Benefits of the WSR-88D over the WSR-57
  • Improved Sensitivity - This is basically a result of a greater amount of power transmitted and a greater ability to distinguish smaller returns. The WSR-88D's ability to detect lighter amounts of precipitation has allowed for the detection of very light precipitation and even subtle clear air boundaries.
  • Improved Resolution - This is primarily a function of angular beam width. The narrower the beam, the smaller the width at a given distance. This will allow the WSR-88D to differentiate between objects, thereby increasing the resolution.
  • Volume Scanning - Rather than scanning along varying azimuth angles (PPI) then stopping to scan vertically (RHI), the radar will automatically scan various elevation angels while spinning around 360° of azimuth. Computers will generate products based on this volume scan.
  • Enhanced Capabilities and Algorithms - Sophisticated computer programs will assist the radar operator to detect various phenomena such as mesocyclones and tornadoes (Tornado Vortex Signature - TVS) and the like. The radar will also have a greater range of reflectivities operating in severe and non-precipitation modes.

Wednesday, April 24, 2013

Principles of Modern Radar: Radar Applications

Principles of Modern Radar: Radar Applications
edited by and James A. Scheer and William L. Melvin
Steer
REVIEWERS NEEDED
The Principles of Modern Radar series is the first "community-reviewed" set of text/references that fully involves the worldwide tribe of radar and EW engineers in the publishing process, from manuscript to bound book (and beyond as we post errata and make corrections to anything we missed in new printings).
We need you to get involved, just like the over 100 members of the radar community who volunteered their time and expertise to make the first two volumes the highest quality text/references available. You can see the lists of reviewers for the first two books here, and here.
If you would like to get involved, please contact Brent Beckley with an idea of which chapter you wish to review.
ABOUT THE BOOK
This unique reference will provide in-depth discussions of the most important application areas in current practice, serving primarily radar practitioners and advanced graduate students. For those needing to become experts in an advanced technology or application area, Radar Applications should be the foundation of their research before they tackle in-depth, single topic advanced books and literature. These advanced books are suggested at the end of each chapter to guide readers toward the best published works.
Principles of Modern Radar: Radar Applications will provide concise descriptions of the purposes, principal issues, and radar methods found in a wide variety of current radar types with military, commercial, and civilian issues. These types of radar include:
  • Continuous wave (CW)
  • Weather and air traffic control
  • Pulse Doppler
  • Fire Control
  • Ground moving target indication
  • Police speed timing
  • Foliage penetrating
This book combines the best attributes of edited and single-author references, drawing on the expertise of authors from academia and industry, all active in both teaching and ongoing research. These experts provide greater depth and experience over the broad range of radar topics than could any single author. A strong team of volume editors and external peer reviewers from the radar community will ensure consistency of structure, level, style, and notation of a single-author text.
TABLE OF CONTENTS
1. Overview (William H. Melvin, James A. Scheer)

2. Continuous Wave (CW) Radar (Samuel O. Piper)
2.1 Continuous Wave Introduction
2.2 CW Radar Configurations
2.3 Unmodulated CW Radar
2.4 Frequency Modulated CW Radar
2.5 Phase Modulated CW Radar Waveform
2.6 Frequency Shift Key CW Radar Waveform
2.7 FMCW Radar Systems
2.8 References
3. Millimeter Microwave (MMW) Applications (Samuel O. Piper, James A. Saffold)
3.1 Introduction
3.2 The MMW Spectrum
3.3 Propagation at Higher Frequency
3.4 MMW Performance Limitations
3.5 Munitions and Seekers
3.6 Passive Detection (Radiometry)
3.7 MMW Radar Applications for the Military
3.8 MMW Radar Applications for the Commercial Market
3.9 Further Reading
3.10 References
4. Fire Control Radar (William G. Ballard, Stephane Kemkemian)
4.1 Introduction
4.2 Airborne Fire Control Radar
4.3 Surface Based Fire Control Radar
4.4 Electronic Counter Countermeasures (ECCM)
4.5 The "AN" Equipment Designation
4.6 References

5. Airborne Pulse Doppler Radar (Aram Partizian)
5.1 Introduction
5.2 Geometry
5.3 The Doppler Shift and Motivation for Doppler Processing
5.4 Range and Doppler Distribution of Clutter
5.5 Contours of Constant Doppler and Range
5.6 Example Scenario
5.7 Pulse-Doppler Conceptual Approach
5.8 Ambiguities, Folded Clutter, and Blind Zones
5.9 Overview of PRF Regimes
5.10 High PRF Mode
5.11 Medium PRF Mode
5.12 Low PRF Mode
5.13 References
>> Check out Pulse Doppler Radar, by Clive Alabaster, available from SciTech and the IET

6. Multiple-Function Phased Array Radar Systems (Melvin Belcher)
6.1 Introduction
6.2 Operational Concepts and Military Utilities
6.3 MPARS Sizing and Performance Evaluation
6.4 Search Sizing
6.5 ESA Overview
6.6 Radar Control and Resource Management
6.7 MPARS Technologies
6.8 MPARS Testing and Evaluation
6.9 Netcentric MPARS Applications
6.10 References
6.11 Further Reading
7. Ballistic Missile Defense Radars (Melvin Belcher)
7.1 Introduction
7.2 BMD Radar System Requirements
7.3 Radar Development for Ballistic Missile Defense
7.4 BMD Radar Design
7.5 BMD Radar Performance Estimation
7.6 References
7.7 Further Reading

8. Early Warning Radar (Alfonso Farina)
8.1 Introduction
8.2 Phased Array Antenna
8.3 Transceiver
8.4 Multi-Core Processors
8.5 Waveforms and Signal Processing
8.6 Plot Accuracy and Resolution for GBEWR
8.7 Tracking
8.8 Electronic Counter Countermeasures (ECCM) Capabilities
8.9 Special Functions
8.10 Conclusions and Further Readings
8.11 References

9. Surface Moving Target Indication (William L. Melvin)
9.1 Introduction
9.2 SMTI Radar Operation
9.3 Signal Models
9.4 SMTI Metrics
9.5 Antenna and Waveform Considerations
9.6 Clutter Mitigation Approaches
9.7 Detection Processing
9.8 Angle and Doppler Estimation
9.9 Other Considerations
9.10 Summary
9.11 Further Reading
9.12 References
10. Air Traffic Control Radar (John Porcello)
12.1 Introduction – The Task of Air Traffic Control (ATC)
12.2 System Requirements/Mission
12.3 Design Issues
12.4 The Future of ATC Radar
12.5 Summary
12.6 Further Reading
12.7 Acknowledgements
12.8 References

11. Space-Based Radar (Samuel Piper)
10.1 Introduction
10.2 Space-Based Radar Systems
10.3 SBR Orbital Relationships
10.4 SBR Target, Terrain and Noise Power
10.5 SBR Waveform
10.6 References

12. Passive and Bistatic Radar (Hugh Griffiths, Chris Baker)
11.1 Introduction
11.2 Bistatic Radar
11.3 Passive Bistatic Radar Waveforms
11.4 The Signal Environment
11.5 Passive Bistatic Radar Techniques
11.6 Examples of Systems
11.7 Conclusions
11.8 References
>> Check out Advances in Bistatic Radar, edited by Hugh Griffiths, available now from SciTech and the IET
13. Weather Radar (John Trostel)
13.1 Introduction
13.2 Typical Weather Radar Hardware
13.3 The Radar Range Equation for Weather Radar
13.4 Doppler Processing
13.5 Hydrological Measurements
13.6 Characteristics of Some Meteorological Phenomena
13.7 Sun Echoes and Roost Rings
13.8 Advanced Processing and Systems
13.9 Further Reading
13.10 References

14. Foliage Penetrating Radar (Mark Davis)
14.1 Introduction
14.2 History of Battlefield Surveillance
14.3 Foliage Penetration SAR Collection Systems
14.4 FOPEN Clutter Characteristics
14.5 Image Formation
14.6 Radio Frequency Interference
14.7 Target Detection and Characterization
14.8 Summary
14.9 Further Reading
14.10 References
>> Check out Mark's book, Foliage Penetration Radar, available now from SciTech and the IET.

15. Materials (Ground) Penetrating Radar (C. Richard Liu)
15.1 Introduction
15.2 Pulsed Ground Penetrating Radar System Design
15.3 GPR System Implementation and Test Results
15.4 Conclusions
15.5 Reference

16. Police Speed Timing Radar (Eugene F. Greneker)
16.1 Introduction
16.2 History of Technologies that Enabled Police Radar
16.3 First Police Radar
16.4 Cosine Error Caused by Improper Operation
16.5 Next Generation S-Band Radar
16.6 Moving to X-Band - 10GHz
16.7 Second Method Used to Achieve the Ferro-magnetic Circulator Function
16.8 Moving Radar with Improved Detection Range Capability
16.9 Moving Mode Police Radar Operation
16.10 Alternative Phase Locked Loop Signal Processing Approach
16.11 Move to K-Band Frequencies
16.12 Police Radar Moves to the Ka Band and Utilizes Digital Signal Processing
16.13 Other Police Operating Modes Made Possible by DSP
16.14 Summary
16.15 References
ABOUT THE EDITORS
James Scheer
Mr. James A. Scheer
Jim Scheer has 40 years of hands-on experience in the design, development, and analysis of radar systems. He currently consults and works part time for GTRI and teaches radar-related short courses. He began his career with the General Electric Company (now Lockheed Martin Corporation), working on the F-111 attack radar system. In 1975 he moved to GTRI, where he worked on radar system applied research until his retirement in 2004. Mr. Scheer is an IEEE Life Fellow and holds a BSEE degree from Clarkson University and the MSEE degree from Syracuse University.
Bill Melvin
Dr. William L. Melvin
Dr. Melvin is Director of the Sensors and Electromagnetic Applications Laboratory (SEAL) at the Georgia Tech Research Institute and an Adjunct Professor in Georgia Tech's Electrical and Computer Engineering Department. His specific expertise includes digital signal processing with application to RF sensors, including adaptive signal processing for aerospace radar detection of airborne and ground moving targets, radar applications of detection and estimation theory, electronic protection, SIGINT, and synthetic aperture radar. He has authored over 150 publications in his areas of expertise and holds three patents on adaptive radar technology. Dr. Melvin received the Ph.D. in Electrical Engineering from Lehigh University in 1994, as well as the MSEE and BSEE degrees (with high honors) from the same institution. He is also a distinguished graduate of the USAF ROTC program.