The Radar Essay, Research Paper
system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, the principle of radar is not confined to any particular frequency range. There are some radar units that operate on frequencies well below 100 megahertz (megacycles) and others that operate in the infrared range and above. The term radar, an acronym for radio detection and ranging, is also used to denote the apparatus for implementing the technique. 1
Principles of Radar
Radar involves the transmission of pulses of electromagnetic waves by means of a directional antenna; some of the pulses are reflected by objects that intercept them. The reflections are picked up by a receiver, processed electronically, and converted into visible form by means of a cathode-ray tube. The range of the object is determined by measuring the time it takes for the radar signal to reach the object and return. The object s location with respect to the radar unit is determined from the direction in which the pulse was received. In most radar units the beam of pulses is continuously rotated at a constant speed, or it is scanned (swung back and forth) over a sector, also at a constant rate. The velocity of the object is measured by applying the Doppler principle: if the object is approaching the radar unit, the frequency of the returned signal is greater than the frequency of the transmitted signal; if the object is receding from the radar unit, the returned frequency is less; and if the object is not moving relative to the radar unit, the return signal will have the same frequency as the transmitted signal. 2
Applications of Radar
The information secured by radar includes the position and velocity of the object with respect to the radar unit. In some advanced systems the shape of the object may also be determined. Commercial airliners are equipped with radar devices that warn of obstacles in or approaching their path and give accurate altitude readings. Planes can land in fog at airports equipped with radar-assisted ground-controlled approach (GCA) systems, in which the plane s flight is observed on radar screens while operators radio landing directions to the pilot. A ground-based radar system for guiding and landing aircraft by remote control was developed in 1960. 3
Radar is also used to measure distances and map geographical areas (shoran) and to navigate and fix positions at sea. Meteorologists use radar to monitor precipitation; it has become the primary tool for short-term weather forecasting and is also used to watch for severe weather such as thunderstorms and tornados. Radar can be used to study the planets and the solar ionosphere and to trace solar flares and other moving particles in outer space. 4
Various radar tracking and surveillance systems are used for scientific study and for defense. For the defense of North America the U.S. government developed (c.1959 63) a radar network known as the Ballistic Missile Early Warning System (BMEWS), with radar installations in Thule, Greenland; Clear, Alaska; and Yorkshire, England. A radar system known as Space Detention and Tracking System (SPADATS), operated collaboratively by the Canada and the U.S., is used to track earth-orbiting artificial satellites. 5
See also stealth technology. 6
Development of Radar
Radar was developed (c.1935 40) independently in several countries as a military instrument for detecting aircraft and ships. One of the earliest practical radar systems was devised (1934 35) by Sir Robert Watson-Watt, a Scots physicist. Although the technology evolved rapidly during World War II, radar improved immensely following the war, the principal advances being higher power outputs, greater receiver sensitivity, and improved timing and signal-processing circuits. In 1946 radar beams from the earth were reflected back from the moon. Radar contact was established with Venus in 1958 and with the sun in 1959, thereby opening a new field of astronomy radar astronomy.
Другие работы по теме:
Radar Applications Essay Research Paper Radar applications
Radar Applications Essay, Research Paper Radar applications by frequency: HF (3 to 30 MHz) The very first British radar system chain home used the HF band, but it was soon realised that these frequencies were becoming too crowded with other users and they suffered from too much external noise for serious use.
Angola Essay Research Paper I feel that
Angola Essay, Research Paper I feel that Angola prison system is a very effective correction system. The video demonstrated how the system has different setups to keep the prisoners working to keep them out of trouble. Although Angola is a rough maximum-security system, it seems to have great control over the inmates.
Press Censorship Essay Research Paper There are
Press Censorship Essay, Research Paper There are many kinds of censorship within our school system. Such as press Censorship, we aren’t aloud to express freely among our school?s newspaper nor
Muscular System Essay Research Paper Do you
Muscular System Essay, Research Paper Do you think muscles are important? Do you have an idea of what they are made of? Well, here is some food for thought: your muscles make up forty percent of your body weight. If you like that interesting fact maybe you’ll learn some more.
Alarms Essay Research Paper Alarm Systems You
Alarms Essay, Research Paper Alarm Systems: You Need One All homeowners should have an alarm system in their home. Alarm systems can help you in times of distress. They can even save your life and keep your belongings from getting stolen. I think that all homeowners should have and alarm system for their safety and the safety of their belongings.
Binary Systems Essay Research Paper Binary systems
Binary Systems Essay, Research Paper Binary systems are a major factor of everyday live. As years pass the use of a binary system has changed dramatically. Throughout this essay I will explain what binary systems are, how they were used in the past, and how they are being used today. A binary system is defined as a numbering system with a base (radix) of 2, unlike the number system which has bases of 10.
Capitalism And Communism Essay Research Paper Capitalism
Capitalism And Communism Essay, Research Paper Capitalism and Communism are two totally different economic systems. Capitalism is a much better economic system than Communism. Capitalism is an economic system characterized by freedom of the market and is the economic system where you do not have freedom because the government will make most of your decisions for you.
The Immune System Essay Research Paper The
The Immune System Essay, Research Paper The immune system is a group of cells and organs that defend the body against invaders causing disease. The immune system is made up of mostly
The Internet Vs The Library Essay Research
Paper The Internet vs. the Library Overall, when one compares the Internet vs. the Library, the Library is superior. This is because, though it takes a bit longer to use, the Library has a standard information research tool; the Dewey decimal system. This organized system makes finding books simple, and with the added assistance of a librarian, finding information can be easy.
Electric Belief System Essay Research Paper The
Electric Belief System Essay, Research Paper The use of eclectic belief systems is the ultimate realization of personal destiny. It is a set of beliefs and practices that have been tailored to the needs of the individual, not of the populus, or the governing geographical authority. It represents an active, positive role of the individual in the direction of his or her life.
Criminal Justice Essay Research Paper In this
Criminal Justice Essay, Research Paper In this paper I will attempt to explain how the United States Criminal Justice System and Ireland has some different characteristics. They both share some of the same practices in each system. I will give a brief history of both countries and the way their system works.
Facism Essay Research Paper Throughout time the
Facism Essay, Research Paper Throughout time the debate upon which is the best system of government has been ongoing. Somewhere between the realms of democracy, socialism, fascism, communism, and monarchism lies the answer to the perfect system. Traditionally speaking, North America has always tried to remain democratic.
Nervous System Adaptation Essay Research Paper Nervous
Nervous System Adaptation Essay, Research Paper Nervous System Adaptation plays a significant role in exercise development as seen by mental imagery, cross education, and coactivation. The body must establish and modify it?s own neural network before it can strengthen. A weight lifter can improve his workouts by understanding the fundamentals of NSA.
Functional Education System Essay Research Paper Sam
Functional Education System Essay, Research Paper Sam Bertolami British Literature 4th Period 8-10-00 When I accepted the position of Secretary of Education I was asked to design and create an education system that is works. Unfortunately it is my belief that no one person can create a fully functional system of education.
Technical Specification Essay Research Paper User manualTechnical
Technical Specification Essay, Research Paper User manual: Technical Specifications: I have designed, as I have already mentioned a system that uses a spreadsheet to record rentals, costs and profit and also calculate the revenue, maintenance costs, profit, profit in percentage and totals of the mentioned values.
Magnetic Spectrum Essay Research Paper Electromagnetic SpectrumAn
Magnetic Spectrum Essay, Research Paper Electromagnetic Spectrum An electromagnetic spectrum is the spectrum in which electromagnetic waves are sent out and in which they can be detected. The spectrum of electromagnetic waves includes the following waves: microwave, radar, satellite, UHF T.V., VHF T.V., FM radio, CB radio, amateur radio, and AM radio.
Health Care Essay Research Paper Health care
Health Care Essay, Research Paper Health care is an issue that everyone has to face no matter where they live. In great Britian thecosts for medical treatment is payed for by the government. In the United States there has beenmuch debate over a national health-care system. As it is today, health-care is paid for by thegovernment, but the money comes from the people s taxes.
Geographical Information System Essay Research Paper GIS
Geographical Information System Essay, Research Paper GIS Geographical Information System originated in the 1960s. During the early days of the technology the use was limited to a small group of practicioners. It is a information technology which analizes, stores, and displays both spatial and non-spatial data.
Metric System Essay Research Paper Metric SystemThe
Metric System Essay, Research Paper Metric System The Metric System, also known as the System Internationale (SI) was developed in France in 1799. The Metric System was created because the French and English were not in agreement politically, therefore the French did not want anything to do with the English including their system of measurements.
Mercury Essay Research Paper MercuryIn Roman mythology
Mercury Essay, Research Paper MercuryIn Roman mythology Mercury is messenger of the gods, and son of the god Jupiter. Mercury is the planet closest to the sun. Its distance from the sun is approximately 58 million km (about 36 million miles); its diameter is 4875 km (3030 miles); its volume and mass are about : that of the earth; and its density is approximately equal to that of the earth.
Mercury Essay Research Paper Laolee XiongPeriod 222697MERCURY
Mercury Essay, Research Paper Laolee Xiong Period 2 2/26/97 MERCURY Mercury is the closest planet to the sun. It s average distance from the sun is approximately fifty-eight million km and it s diameter is 4875 km, making it the second smallest planet in our solar system. It s volume and mass are about 1/18 that of the earth and it s average density is approximately equal to that of the earth.
Gps Essay Research Paper Describe how GPS
Gps Essay, Research Paper Describe how GPS works and how normal citizens have been able to use it to make their lives easier. GPS is a global positioning satellite that is used to show the exact position on earth that you are. This system is used in many ways. Many people in a new city use rental cars. These people will probably get lost.
Where Did UNIX Come From And Why
Are There Different Versions Of UNIX? Essay, Research Paper Where Did UNIX Come From and Why Are There Different Versions Of UNIX? The first efforts at developing a multi-user, multi-tasking operating system