Air Surveillance Radar

Abstract

This paper briefly explores the history and origins of air surveillance Radio Detection And Ranging (RADAR) radar systems and how they were developed in three major countries involved in World War II. These countries are the United States, Britain and Germany. Also discussed are the basic components of an air surveillance radar systems and what parts they play. The health concerns of Radio Frequency (RF) radiation such as cancer, reproductive malfunctions and cataracts will be discussed along with environmental and economic impacts. There are multiple political influences and implications associated with air surveillance radar. Wind energy sites and national security and military readiness are two that will be discussed. Also the degradation of the National Air Space (NAS) and military radar systems in the United States and how it has led to the search for new systems to better serve commercial and military aviation. This paper explores and discusses the many markets that use air surveillance radar and the companies that have invested in the development. Also discussed is the proof of concept Multi-Mission Radar that has been developed for use by the United States Army.

Air surveillance radars are designed to detect, locate, track and classify a wide range of targets (SRC, Inc., 2016). Radar uses electromagnetic energy that is transmitted toward objects and observes the echoes returned from those targets (Skolnik, M. I., 2015). The information received includes location, speed, size, and altitude. Air surveillance radar systems are capable of detecting and tracking aircraft at altitudes below 25,000 feet and within 40 to 60 nautical miles of their positions. What sets Radar apart from other sensing devices such as optical and infrared, is its ability to detect faraway objects under adverse weather conditions and to determine their range with precision (Skolnik, M. I., 2015) .
The origins of Radio Detection And Ranging also known by the acronym RADAR, dates back to the late 1880s with the experiments on electromagnetic radiation experiments conducted by the German physicist Heinrich Hertz. He set out to experimentally verify the earlier theoretical work of Scottish physicist James Maxwell (Skolnik, M.I., 2015), which he did using an apparatus operating at 455MHz similar to a pulsed radar. This apparatus was the Oscillator. In 1904 a patent was issued to German engineer, Christian Hülsmeyer in several countries for a device that would assist in obstacle detection and ship navigation based on the principles demonstrated by Hertz (Skolnik, M.I., 2015). This device was known as the “telemobiloscope” which was a transmitter-receiver system that detected distant metallic objects by means of electrical waves (Holloman, M., 2007). After building his invention, Hülsmeyer demonstrated it to the German Navy but there was no interest.

The Oscillator (famousscientists.org, 2015) Telemobilscope (radarwaorld.org, 2007) The 1930s is when the serious development of radar started. With the development of World War II, countries such as the United States, Japan, Great Britain, Germany, France, Italy, the Netherlands and the Soviet Union needed a system that would help with detecting approaching long-range aircraft to enable military defenses sufficient time to react and counter incoming threats (globalsecurity.org). These countries had numerous inventors, scientists and engineers that contributed to the development of radar. The development of air surveillance radar at the U.S. Naval Research Lab (NRL) in Washington, D.C. started in 1930 when Lawrence A. Hyland, an American electrical engineer, observed that an aircraft flying through the beam of a transmitting antenna caused a fluctuation in the received signal (Skolnik, M. I., 2015). However, due to no interest by the Navy’s higher authorities, the pursuit of development was halted. Until the ability of using one antenna to transmit and receive was the value of a radar system to detect and track aircraft was fully recognized (Skolnik, M. I., 2015). The first radar to detect aircraft by the United States Army was the SCR-270. It was the SRC-270 that detected the approach of Japanese war planes on Pearl Harbor.

SCR-270 (Wikipedia.org)

Britain started their radar research for detecting aircraft in 1935. The first British radar system was developed by Robert Watson-Watt and was operational by September 1939 at the outbreak of war (Hollmann, M. 2007). This system was known as the Chain Home or CH. The CH radar was the first to be organized into a complete defense system, and the first to be used in wartime operations. The Chain Home radars allowed Britain to deploy successfully its limited air defenses against the heavy German air attacks conducted during the early part of the war (Skolnik, M.I., 2015).

Chain Home or CH Radar (flyertalk.com)

Germany was the farthest developed country when it came to radar at the start of World War II. Germany’s radar development started with Christian Hülsmeyer in 1904. However his invention was an idea too early for its time (Hollmann, M., 2007). Between the years 1928 and 1940, modern radar was developed by a prolific inventor and a specialist on microwave technology, Dr. Hans E. Hollmann. In 1928, Hollmann and two other men started a company called GEMA. In autumn of 1934, they developed the first radar transmitter and in 1935, developed a pulse radar. Using “Braunschen” tubes, GEMA developed a radar system that could detect both planes and ships in 1935. The land based radar was called “Freya”. During the war, a radar unit call the Wuerzburg-Riese was developed by paring the Freya with a radar called the “Wuerzburg”. The Wuerzburg was developed 1936 by a microwave department set up at Telefunken in 1933 based on Hollmann’s work. The radar was originally called the “Darmstadt” (Hollman, M., 2007). The Freya would detect and track incoming aircraft and the Wuerzburg would determine the exact range and altitude as the aircraft came closer (Hollmann, M., 2007). These radars were very effective and contributed to 50,000 bombers being shot down during World War II.

(absa3945.com)

A basic air surveillance radar system is made up of a transmitter, duplexer, antenna, receiver, signal and data processor and display console.

The transmitter produces high power radio frequency pulses of electromagnetic energy that are sent out by the antenna. The transmitter of a radar system must be efficient, reliable and easily maintained (Skolnik, M. I., 2015). Also, a transmitter should generate a stable, noise free signal, provide the required bandwidth for the transmitted and received signal and generate enough energy to detect targets. There two main types of transmitters used on surveillance radars. The keyed-oscillator type where a magnetron produces the radio frequency pulse or what is used in many recently developed radar sets, Power-Amplifier-Transmitters (PAT). In the PAT systems the transmitting pulse is caused with a small performance in a waveform generator (radartutorial.eu).

The duplexer is used in radar systems when a single antenna is used for both transmission and reception (Varshney, 2002). What the duplexer does is switch the radar system from transmit mode to receiver mode. Since it is crucial to switch from transmit to receive as fast as possible, it is not practical to use mechanical switches. That is where the duplexer comes in because it can make this switch in microseconds. Most common used duplexers used in radar systems are waveguide and hybrid-ring duplexers (radartutorial.eu).

Duplexer
Duplexer

(Wikimedia.org)

The antenna is mounted on a tower where it continually rotates and transmits electromagnetic waves that reflect from the surface of objects (Faa.gov, 2014). The antenna also receives the reflected electromagnetic waves known as echoes and sends them to the receiver. The antennas are made of a primary scan and a secondary scan. The primary radar scan receives its own emitted signals and evaluates the returned echo from the target (radartutorial.eu). The secondary radar scan does not emit signals. It receives transmitted signals from targets that have been interrogated by the primary radar scan. In order for the target to respond, they have to be equipped with a transponder. The secondary radar scan provides information such as altitude, speed, and identification codes. Primary Radar Antenna
Primary Radar Antenna
Secondary Radar Antenna
Secondary Radar Antenna

(The Boston Globe, 2005) A radar system also has a receiver which filters the desired echo signals from clutter and receiver noise that interfere with detection (Skolnik, M. I., 2015). Also, the receiver must be able to amplify weak signals to where the receiver output is strong enough to actuate a display. The dynamic range of the receiver has to be large enough to be able to detect weak signals in large clutter echoes by recognizing the Doppler frequency shift of the desired moving targets. A part of the receiver that determines the presence or absence of targets while rejecting unwanted signals due to ground clutter, sea clutter, weather, radio-frequency, noise sources and intentional jammers is known as the signal processor (Farina, A., 2006). The small moving targets can be separated from the larger non-moving targets by noting the change of the Doppler frequency produced by the moving targets. Also part of the receiver is the data processor. This unit is used to extract a vast amount of information from the raw radar signals and present this information in a variety of graphic and alphanumeric ways on the displays (globalsecurity.org). Information that the display receives from the processor includes the target’s size, speed, range, altitude and identification code. The display for a radar system or as known to those that use them, the radar scope, is essentially a television or computer screen. The display is used by the operator to track targets. For many years the cathode-ray tube (CRT) has been the preferred technology for displaying information ever since the early days of radar (Skolnik, M. I., 2015). Over the last decade or so, flat-panel screens have made their way into the radar world due to their considerable improvements and their use of less space. Plan position indicator (PPI) is a commonly used radar display. PPI provides a map like presentation in polar coordinates of range and angle (Skolnik, M. I., 2015). A PPI display uses a radial sweep which pivots at about the center of the presentation and rotates just about as fast as the antenna. The result is a map-like picture of the area covered by the radar beam (radartutorial.eu). On some radar displays the operator is able to off-set the sweep origin in order to see more of a certain area. Display from a cathode-ray tube PPI scope Display from Flat Panel PPI scope
(radartutorial.eu, 1993) (metalcraft.com, 2009)
So in summary, air surveillance radar systems work by the transmitter generating a high-power signal that is emitted by the antenna into the air toward objects that are being tracked. The same antenna that transmitted the signal then receives the signals that are reflected back off the objects and sends them to the receiver. In order for the same antenna to be able to transmit and receive, a duplexer is used to switch between both modes in the matter of nanoseconds. The receiver then sends the raw radar signal to the signal and data processors to separate the moving targets from the stationary targets and also to process any information that the transponders send back. The processors then convert that raw signal into data that can be displayed onto the radar display giving the operator the information they need to know about the target.

(hammad666.blogspot.com, 2015)

One environmental issue that comes into play with air surveillance radar systems are wind farms. Depending on their location, wind turbines may interfere with some types of civilian and military radar, causing “clutter” on the radar display (Thales Group, 2015). Multiple studies have shown that wind turbines cause false targets and also cause the real targets to be lost. In some instances the troubles these wind farms cause may be great enough in the vicinity where radar systems are set-up to not radiate between certain degrees of the radius it covers. This causes the safety of air traffic to be diminished. Since these wind farms may contain up to a thousand individual towers with huge blades, the developers must consider the impact that the wind farm could have to the region’s civil and military air surveillance systems (Booz Allen Hamilton, 2016). These types of concerns and impacts to air surveillance radar systems are reasons why wind farm developers face objections from aviation stakeholders.

Alta Wind Energy Centre (Power Technology, 2013)
The effects of these two systems work both ways. Wind turbine project committees have to spend more time and money trying to find ways to mitigate the effects that the turbines would have on radar systems in the area. Since most air surveillance radar systems cover a 60 nautical mile radius, which could have an economic effect on cities relying on jobs that the construction of a wind farm could create.
With the United States Air Traffic Control (ATC) systems being outdated and not performing adequately, manufacturers of air surveillance radar systems have the opportunity to work on and pitch the abilities of their systems. Many manufactures such as, SRC, Inc., Thales Group, Lockheed Martin, and Raytheon are some of the leading sellers of surveillance radars and employers of radar technicians. They are continuously working on systems that would help track non-traditional aircraft such as, ultralights, unmanned aerial vehicles and even birds (SRC, Inc., 2016). As mentioned before, Wind farms are a huge interference concern. SRC, Inc. has developed a low cost radar that helps fill gaps that are created by wind farms called the LSTAR Air Surveillance Radar. [pg. 8]

LSTAR® Air Surveillance Radar (srcinc.com, 2016)
Raytheon was a big winner when the Federal Aviation Association (FAA) and Department of Defense (DoD) decided to purchase Raytheon’s Airport Surveillance Radar (ASR-11) which is a digital radar that replaced the analog ASR-9 in 2003. According to an article written by Janet Kopec for Raytheon dated October 28, 2003, the FAA and DoD planned to purchase and deploy over 300 ASR-11 units over several years. This contract had the life time value of $620 million (Kopec, 2003).

Abilene ASR-11 Radar Antenna (Faa.gov, 2014)
Air surveillance radars play a big role in the air transportation industry. With more that 848.1 million scheduled service passengers flying in, out and around the United States in 2014 (USDOT, 2015), it is imperative that the air surveillance radar systems can keep track of the 9,487,900 flights. According to an International Air Transportation Association (IATA) press release dated June 8, 2015, the industry made a net profit of $16.4 million in 2014 and had a 2015 outlook of $29.3 billion net profit. If air surveillance radar systems did not keep-up with the latest and greatest technology and find ways to help air traffic controllers keep aircraft and people safe, they would hurt the aviation business.

Display showing air traffic over the United States (Reuters/Larry Downing, 2015)
There have been many health concerns by people who live or routinely work around radars. Some of those health concerns include cancer, cataracts, reproductive malfunctions and behavioral or developmental changes in children (World Health Organization, 2016.). Radiofrequency (RF) and Microwave (MW) radiation are types of energy emitted from air surveillance radar systems. If these types of radiation are absorbed in large enough amounts by materials containing water, such as foods, fluids, and body tissues, it can produce heat which can lead to burns and tissue damage (American Cancer Society, 2016). Although RF radiation does not cause cancer by damaging DNA cells, there has been concern that it might have biological effects that could result in cancer. Most people are exposed to very low levels of man-made RF/MW radiation every day from things such as radio and television broadcasts, cell phones and use of Bluetooth and WiFi. (American Cancer Society, 2016). The people that work around air surveillance radars such as, maintenance technicians, air traffic controllers and others that work in close proximity to air surveillance radar systems are exposed to much higher levels of RF radiation. Personnel that work with radar systems are at risk of developing cataracts. In simple terms, a cataract is the clouding of the eye’s lens (Boyd, 2014.) Exposures to high levels of radio waves and microwaves usually above 100 mW/cm2 have been found to cause cataracts in radar workers. The cause of these cataracts is believed to be from intense heating caused by radiation and the prolonged exposure. Studies suggest that personnel need long periods between exposures to allow the body to repair itself.

Cataract (alfamilyeyes.com, June 17, 2015)

Reproductive malfunctions have been a health concern when it comes to exposure to air surveillance radar systems. Testicles are a primary concern due to their inability to dissipate heat. Testicular function is strongly influenced by temperature, and increased heat from RF radiation can reduce sperm cell survival. In a collaborative study between the US Army Biomedical Research and Development Laboratory (USABRDL) and the National Institute for Occupational Safety and Health (NIOSH), a group of radar operators were compared with an unexposed control group. Although there were no differences in the endocrine variable between the groups, the radar operators had a lower sperm concentration than the unexposed control group (Robson, 2001). According to a document by the Health Protection Agency dated April 2012, multiple studies done on lab animals did not show any significant effects on mothers and offspring when exposed to normal RF radiation levels.
War is a political issue that has influenced the development of air surveillance radar systems. As stated earlier in this paper, air surveillance radar systems were primarily developed during World War II to help defend against long range bomber aircraft and fighter aircraft conducting air raids. The influence of war on air surveillance has continued throughout the years and many wars. The other primary use of air surveillance radars that has been influenced by war is the detection of ballistic missiles. During the 1950s, the U.S. progress in developing long-range missiles, combined with evidence that the U.S.S.R. was also developing these weapons, led to more intense efforts to develop missile defenses (DoD MDA, 2016). These missile defense systems have air surveillance radar systems incorporated into them to provide the operator the altitude, range and speed of tracked missiles. The influence for this type of defense has led to the development of the Upgraded Early Warning Radars (UEWR), COBRA DANE radar, Army Navy / Transportable Radar Surveillance (AN/TPY-2), Sea-Based X-Band (SBX), and SPY-1 radar. Each one of these systems are deployed in different environments to protect the United States from potential enemies. Sea-Based X-Band Radar (Missile Defense Agency, 2015)
Sea-Based X-Band Radar (Missile Defense Agency, 2015)
COBRA DANE Radar (Missile Defense Agency, 2014)
COBRA DANE Radar (Missile Defense Agency, 2014)

With North Korea and Iran developing potentially threatening nuclear programs, the demand for radar surveillance has increased by countries such as South Korea, Saudi Arabia, Israel and United Arab Emirates (Mangiola, 2014). The Air and Missile Defense Radar (AMDR) market, which includes land-based systems, naval systems and airborne systems, will grow to reach $10.4 billion by 2020 from its current $7 billion. Even with the United States and Europe, two countries that have faced budget cuts, have put money from other military programs toward new radar-development programs. The U.S. Navy plans on replacing its Aegis-based radar systems with dual-band radar systems. The birth of dual-band, ship-based radar has spread interest and investment globally (Mangiola, 2014). The degradation of the air surveillance radar systems serving the National Air Space and the United States military are a huge influence on the technological advances of air surveillance radars. The U.S. Navy has been pushing for a new and improved air surveillance radar system for their aircraft carriers and amphibious warships to replace the SPS-48 and SPS-49 currently being used (Howard, 2013). With the high cost of maintaining the SPS-48 and SPS-49 and the budget constraints on military spending, The Navy is in need of a lower-cost radar system. Another influence on finding a new radar system for the Navy is to have a common radar system on aircraft carriers and amphibious warships. The radar system that the Navy has decided to go with is the Enterprise Air Surveillance Radar (EASR) which will be placed on future naval aviation ships. The EASR is a phased-array radar and is not as complex as the current Dual Band Radar used on current naval aviation ships. In a move to cut the cost of the EASR, the Navy has created a $6 million EASR study and development contract with Raytheon and Northrop Grumman (Osborn, 2015). SPS-48 (ITT Gilfillan, N.D.) SPS-49 (Wikipedia.org, 2008) The United States government’s green energy policies have been a political implication to air surveillance radar systems used by the military and national security agencies. According to an article written by Lisa Linowes, our air space has been made less safe by turbines and our national security compromised because of reckless policy of siting wind towers within 50 miles of radar installations. Wind turbines can create holes in military radar coverage, cloaking aircraft flying overhead (Linklater, 2008). But with President Obama’s fight to find a solution to “climate change” wind two giant wind projects have been scheduled for immediate development near vital U.S. defense facilities. (Delingpole, 2015). One site scheduled is the Desert Wind project in North Carolina which would have 150 turbines, each over 500 feet tall. This site would interfere with one of only two Relocatable Over The Horizon Radar (ROTHR) sites in the United States. The ROTHR, located at a Hampton Roads Naval military base, is a key part of U.S. homeland defense. The second wind turbine site known as Pantego Wind in North Carolina will be built near Seymour Johnson Air Force Base where one of the base’s primary mission is to train fighter pilots to fly low-level routes to avoid radar detection (Delingpole, 2015). According to the Commanding Officer of Seymour Johnson, Colonel Jeannie Leavitt, this site near Seymour Johnson Air Force Base would make low altitude air-to-air intercept, low-altitude navigation and maneuvering training less realistic and impossible to complete leaving combat fliers less proficient. Even though military radar experts understand and know how these wind farms have and are damaging national security, they have been quieted by politics and money so Washington can protect its pet policies and political friends (Linowes, 2011).

This map shows wind turbine locations in the United States. The red dots are those wind turbines that are visible to radar systems. (Sandia National Laboratories, 2015)
This map shows wind turbine locations in the United States. The red dots are those wind turbines that are visible to radar systems. (Sandia National Laboratories, 2015)
(Sandia National Laboratories, 2015)
(Sandia National Laboratories, 2015)

One alternative to the traditional air surveillance radar systems is the use of Phased Array technology. Currently, several types of air surveillance radars are used to detect and track aircraft in the United States airspace. Air Surveillance Radar (ASR) tracks aircraft within 60 nautical miles of an airport and the Air Route Surveillance Radar (ARSR) track aircraft long range as they fly between airports. However, these radar systems are based on older technologies that use many mechanical components that require frequent and costly repairs (Robinson, 2012). A multi-year study being conducted by a research team from Georgia Tech Research Institute (GTRI) along with the FAA are examining the feasibility of single system based on phased-array technology, a design that uses solid-state electronics, to replace the group of conventional radars. Multifunction phased-array radar (MPAR) is specifically being considered by the FAA due to its capability to surpass current technologies, reliability and ease of maintenance. Since phased-array radars are fully solid state and employ hundreds to thousands of fixed antenna elements transmitting and receiving a single beam, it offers redundancy and continues to operate if some of the elements were to fail (Robinson, 2012). While conventional radars use a rotating dish-like antenna and multiple moving mechanical parts, the radar systems could go completely down just from one parts failing.

Multifunction Phased-Array Radar (MPAR) (noaa.gov, 2007) In London, another alternative to air surveillance radar is being researched. This radar system is known as “passive radar”, which relies on existing signals, such as television and radio broadcasts, to illuminate aircraft (The Economist, 2013). It incorporates multiple antennas listening for broadcast tower signals and the reflections from those signals that have reflected of aircraft. The position, direction and speed of nearby air craft can be determined. Even though passive radar requires a lot of processing power, but does not need a transmitter, it is more cost effective than conventional air surveillance radar systems. With passive radar not emitting any signals of its own, it would benefit militaries, by enabling them to covertly detect objects. For commercial use, the use of television signals may work better in areas where conventional radars experience interference by wind turbines (The Economist, 2013).

Broadcast tower in London (The Engineer, 2010)
The future of air surveillance radar systems in the United States will be based on the needs of the Federal Aviation Administration to strengthen the National Air Space system. With air passenger growth on U.S. flag carriers steadily rising, domestic flights are increasing and causing longer delays at airports. One big reason for this is that air traffic controllers are experiencing problems with the current systems. The FAA is currently working on a solution for these problems which is the Next Generation (NextGen) Air Transportation System (Cox, 2007).
Automatic Dependent Surveillance-Broadcast (ADS-B) is a satellite-based successor to radar. ADS-B uses Global Navigation Satellite systems technology and simple broadcast communications link as its fundamental components. Current radar systems transmit a signal towards the aircraft and receive the reflected signal back to interpret the information. As the typical air surveillance radar system rotates at a rate of approximately 5 Rotations Per Minute (RPM), the time between signal returns is approximately 12 seconds (ADS Technologies, 2016) creating delays in information that air traffic controllers get and then have to voice broadcast that information to other aircraft in the area that need to know the location of other aircraft. With ADS-B using Global Navigation Satellite System (GNSS) technology, it is capable of deriving a precise location of the aircraft and combine the position with any other information such as, speed, heading, altitude, aircraft type and flight number. ADS-B then simultaneously broadcasts all the information to other ADS-B equipped aircraft and to ADS-B ground and satellite transceivers in real time (ADS-B Technologies, 2016). The FAA has mandated that in order to fly in most controlled airspace, aircraft must be equipped with ADS-B by January 1, 2020 (FAA, 2016).

ADS-B Diagram (Smyrna Air Center, 2012) The siting of wind farms in the close proximity of air surveillance radar systems has opened the market for companies to create systems that would help mitigate the impact that wind farms have on the detection of aircraft. Terma Radar Systems has manufactured an air surveillance radar that is tolerant of wind farm effects called the SCANTER 4002. This radar is an X-band, two dimensional radar that provides both Moving Target Indicator (MTI) and normal, non-moving radar video simultaneously. It is able to detect and separate air targets and land targets thus being able to detect aircraft flying over wind farms unlike current air search radar systems that lose them. The SCANTER 4002 can be used as a supplemental, gap-filling radar or as a replacement radar in air traffic control systems (Terma, 2012).

SCANTER 4002 Radar (Terma, 2015) Another company that has jumped into the market of creating a system to help fill the gaps created by wind farms is SRC, Inc. They have developed the LSTAR Air Surveillance Radar systems. These systems provide 360 degree, 3-D electronic scanning capabilities that provide reliable detection and tracking of aircraft (SRC, Inc., 2016). This portable, lightweight system makes it ideal to relocate to different areas depending on the configuration of the wind turbines. LSTAR Sir Surveillance Systems (ausa.org, 2011)
As long as wind energy is being pursued as an alternative energy source, the market for gap-filling and/or replacement radar systems that are tolerable to the effects of wind turbines will continue to grow. SRC Inc. has built a proof of concept tactical radar for the United States Army. This prototype multi-mission radar (MMR) performs air defense surveillance, air traffic control, counterfire target acquisition and fire control in a single, stand alone, transportable system (SRC, Inc., 2014). This radar system cover 360 degrees in azimuth, utilizing a full electronically-scanned array antenna that scans both azimuth and elevation. When utilized for air defense or air traffic control it can track up to 1,000 targets, 100 projectiles, such as rockets, artillery and mortars when utilized for counterfire target acquisition and 50 simultaneous targets for fire control (SRC, Inc., 2014). By incorporating the capability to perform multiple missions into one radar system, gets rid of having to transport, set-up and maintain multiple systems and cuts down on the size of crews having to be deployed.

Multi-Mission Radar (MMR) (SRC, Inc., 2014) Another trend in the use and development of air search radar is for the tracking of birds and bats. Even though radar has been used for many years in tracking the migration of birds, it has only been in the past couple of decades that the safety of aviation has pushed the recent development of avian radar systems. One of the most common wildlife hazards to aviation safety are bird strikes (Dolbeer et al. 2000). The number of bird strike reports from civil aircraft has risen steadily from 1,795 strikes in 1990 to 13,159 in 2014 (Dolbeer et al. 2015). Since different species move about at different times of the day, the use of avian radars are very helpful to air traffic controllers to detect birds at night and relay that information to pilots or re-route aircraft to avoid large flocks of birds. Avian radars also aid wildlife management in gathering data on patterns and trends of bird species. This helps in applying techniques to manage the bird populations around airports (Loomacres, 2015). Many companies have invested in the avian radar system market by developing systems. Detect, Inc. has developed the MERLIN Avian Radar System; SRC Inc. has the BSTAR Avian Surveillance and Warning System and Accipiter has produced the Accipiter Avian Radar. As long as there is a risk of birk strikes there will always be a market for development and growth of avian radar detection systems. MERLIN Avian Radar System (DeTect, Inc., 2002) BSTAR Avian Surveillance and Warning System (SRC, Inc., 2016)

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