History of radar

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The history of radar describes the development of radar systems from the first attempts in 1904 through the research competition during the Second World War to the latest technologies in space travel and the automotive industry.

Discovery and first practical radar location

Patent of Hülsmeyer's Telemobiloskop (April 30, 1904)

Heinrich Hertz found in 1886 during the experimental detection of electromagnetic waves that radio waves are reflected by metallic objects.

Eleven years later, the Indian Jagadish Chandra Bose repeated the Hertzian experiments in Calcutta , but this time with a shorter wavelength than Hertz. On the basis of these experiments, Bose developed, among other things, the waveguide - an important component of radar devices.

The first practical localizations and distance measurements using radio waves were carried out in 1904 by the German high-frequency technician Christian Hülsmeyer . He developed and presented the first functioning radar system that worked with 50 cm waves and already had the classic transmitter configuration consisting of a horn antenna with a parabolic mirror. Since there were no tubes yet, the transmitter ran with a spark inductor . The receiver was a coherer with a mechanical time block that ran synchronously to the transmission to suppress interfering external signals. He called the radar device presented to the Navy on the Rhine near Cologne-Deutz, a telemobiloskop, and it was able to report acoustically the radar echo signals that were thrown back from a ship at a distance of 3 km and thus locate larger metallic objects.

A patent application was filed for the underlying process on April 30, 1904 in Germany and England. Since the range did not exceed the visible and audible range at that time, the German military was not interested in the device and the development was almost forgotten.

The title of patent specification No. 165546 read:

“Procedure for reporting removed metallic objects to an observer using electrical waves.
The present invention relates to a device by which the approach or movement of distant metallic objects (ships, trains or the like) is reported to an observer by means of electrical waves through audible or visible signals [...] "

Probably unaffected by Hülsmeyer's patent, the basic principles of radar were sketched out in the USA by the science fiction author and inventor Hugo Gernsback in his science fiction novel Ralph 124C 41+ in 1911 . Gernsback's book goes back to a serial novel that was published in the tech magazine Modern Electrics between April 1911 and March 1912.

In 1916 the engineer and author Hans Dominik approached the Reichsmarineamt with a prototype he had developed. The Reichsmarineamt refused, however, because a mission for the First World War was no longer an option.

The search for new physical principles to solve the problem of recognizing and locating air and sea targets led to the development of radar technology in several countries almost simultaneously in the mid-1930s.

Development during the Second World War

History of radar development in Germany

Radar device "Würzburg C" (1942)

The breakthrough in widespread use of radar technology did not come until World War II . Rudolf Kühnhold , the scientific director of the intelligence test department of the Reichsmarine , pushed the development forward decisively. In 1934, the first tests were carried out in the port of Kiel with an apparatus he had developed, which was called DeTe device ( decimeter telegraphy ) for camouflage . During his experiments, he was not only able to locate ships as planned, but also aircraft flying over the harbor.

The distance up to which the radar worked was still unsuitable for widespread use, but as early as October 1934 distance measurements were up to around 40 km. One of the first manufacturers of radar devices was GEMA (Society for electroacoustic and mechanical apparatus mbH, Berlin) , founded in 1934 . Hans Karl Freiherr von Willisen and Paul-Günther Erbslöh developed and tested the Freya , Mammut (PESA), Wassermann and Seetakt systems, as well as sea art equipment , in Pelzerhaken . After the end of the war, GEMA was dissolved as an armaments company and the locations in the alternate quarters Pelzerhaken and Lensahn were dismantled.

In addition to GEMA, Telefunken had the largest share of German radar technology with the ground-based fire control radar Würzburg and Würzburg-Riese and the first on-board radar system available in Germany for night hunters ( "Lichtenstein device" ). Of Siemens and Halske were hunting lodge - and Flensburg devices developed. Other companies active in the field were Blaupunkt GmbH (formerly Ideal-Radio ) and C. Lorenz AG (both in Berlin).

The following systems have been developed:

  • active monostatic radar devices that work with a transmitter and receiver at one location, called radio measuring devices (FuMG);
  • passive defensive radar warning receivers, which were only used to warn of hostile active radar from aircraft and ships, called radio measurement observation devices (FuMB), such as
  • passive offensive radar receivers for approaching enemy aircraft with their own active radar, such as
  • parasitic bistatic radar devices that misused a hostile radar system ( chain home ) for target illumination , such as
    • Little Heidelberg

During the Second World War, radar technology gained great importance in naval warfare, but above all in air warfare, and was used there in connection with flak positions and for commanding fighter planes . The first successful radar-guided interception operation in history was on December 18, 1939, when 24 British bombers flew an attack on Wilhelmshaven . After their radar location, ten bombers were shot down by fighters and three were badly damaged. The more than 1000 km long Kammhuber Line from Denmark to Northern France was a defense system against night bomber squadrons on the German Reich. It consisted of radar sets of the types Würzburg Riese and Freya .

Until the 1950s, the term "Funkmeß" and, more rarely, "radio touch sense" was used for the radar method in German-speaking countries .

History of radar development in England

While radar development in Germany was initially concerned with the detection of ship targets, in England the detection of aircraft was the starting point for development.

Radio pulses had already been used in ionosphere research and the height of the ionosphere was determined from the time it takes for the reflected signal to arrive. This method has now been further developed for radio location. The head of the Radio Research Station in Slough, Robert Watson-Watt , and his colleague, the physicist Arnold Wilkins , laid on February 12, 1935 its report on the topic detection and tracking of aircraft by radio before (title Detection and location of aircraft by radio methods ) , in which they already described all the essential features of radar.

The first field test was carried out on February 26, 1935. The BBC station in Daventry sent a signal with a wavelength of 49 m. This was tailored to the wingspan of conventional bomber planes, which were about half this length and thus represented half-wave dipoles. Good reflective properties were expected from this. A mobile receiving station, equipped with a cathode ray oscilloscope that was very modern at the time , was about 10 km away. The test aircraft flying over this area, a Handley Page Heyford , actually produced an additional point of light on the oscilloscope screen through the radio waves reflected off its fuselage. The aircraft could already be tracked up to a distance of 13 km during this first test.

After these successful test results, the English radar development began with great effort. As early as January 1936, solutions had been found for all aspects of radar location (distance, elevation angle and location direction). Even the principle of a tracking radar could be demonstrated in practice on June 20, 1939 in front of Winston Churchill .

Range of the chain home system

In 1937 work began on installing a chain of 20 coastal radar stations, the so-called Chain Home , on the east coast of the British Isles . It worked at a wavelength of 10 to 13.5 m (22 to 30 MHz), transmitted 25 pulses per second with 200 kW power and had a range of 200 km. From Good Friday 1939 (April 7th) the Chain Home was in continuous 24-hour operation.

The Germans discovered the tall masts installed for this purpose and undertook two reconnaissance flights with the airship LZ 130 Graf Zeppelin II in May and August 1939 along the British east coast to the Shetland Islands in order to investigate the state of English radar technology. However, they did not find any radar signals, as they expected signals in the range of 1.5 to 0.5 m wavelength, but the Chain Home worked with a much larger wavelength, which German engineers found completely absurd.

Chain Home had a long range, but could not detect any low-flying aircraft. Therefore Chain Home Low was also installed, a low-level radar chain with a range of 80 km at 1.5 m wavelength (200 MHz).

The radar chain proved to be an important advantage in the Battle of Britain , as the German attacks could be detected in time.

Anode block of the multi-chamber magnetron with six resonance chambers by Randall and Boot, 1940.

Soon, radars were also developed for use in aircraft. The first devices were only of moderate use due to their wavelength of at least 50 cm. On February 21, 1940, the British researchers John Turton Randall and Harry Boot succeeded in setting up the first laboratory device, a magnetron, for generating 10 cm waves. From this, the H2S device was developed, an on- board radar for aircraft with which the contours of the landscape were displayed as on a map. The first use took place on January 30th and 31st, 1943 in a bombing raid on Hamburg.

So-called chaffs were developed against radar - a simple means of jamming radar. Germany and England had developed this remedy independently of one another and kept it secret so as not to reveal how their own radar could be disrupted. Operation Biting shows the importance the British attached to the German radar : in February 1942, in a commando operation with paratroopers, they captured parts of the German Würzburg radar . They found out its wavelength (53 cm) and discovered that it could not be varied. This finding, they used the first time in July 1943, ahead of flying reconnaissance aircraft of the RAF threw in the Operation Gomorrah , the major attack on Hamburg in July 1943 (it caused the first firestorm in a German city), chaff to disrupt German radar stations with the exact length 26, 5 cm. These are strips of metal foil cut to about half the wavelength of the radar equipment used and dropped in large quantities from aircraft. 92 million strips, equivalent to 40 tons, were dropped. On the German side, the development of a suitable antidote did not take long: the improved Würzburg radar device could separate moving objects such as aircraft from the stationary metal strips and determine the speed of the target using the Doppler effect.

History of radar development in the Soviet Union

The fact of an independent development in the Soviet Union is hardly mentioned by Western sources. The Soviet radar development took place under the conditions of the international isolation of the Soviet Union and later the outsourcing of construction and production capacities to the east.

Popov transmitted the first radio signals in Saint Petersburg in 1895 and discovered the property of the reflection of radio waves on objects. In the 1920s, Russian and Ukrainian scientists made theoretical preliminary work on the use of reflective location using electromagnetic waves. Michail Alexandrowitsch Bontsch-Brujewitsch , Arenberg and Vwedenski investigated the reflection behavior of electromagnetic waves. By Mandelstam made and Papaleksi phasometrische distance measurements for determining the height of the ionosphere with electromagnetic pulses.

The idea of ​​using radio waves to detect and determine the location of missiles arose at the same time in two administrations of the People's Commissariat for Defense - in the military technical administration in 1930 in the plan for a reconnaissance device for the anti-aircraft cartillery and in the air defense administration in 1932/33 to improve air reconnaissance. At the end of 1933, on the initiative of the military engineer MM Lobanow, investigations into the location of reflections with decimeter waves were started in the Central Radio Laboratory. Under the direction of JK Korowin, an aircraft was located for the first time with an experimental set-up that consisted of a 60 cm continuous wave transmitter, a super regenerative receiver and two parabolic antennas for transmission and reception.

In January 1934, under the leadership of academician Abram F. Joffe, a consultation of well-known specialists took place, which supported the ideas of the engineer PK Ostschepkow for a system of air space reconnaissance using electromagnetic waves. Ostschepkow published his thoughts on a reconnaissance system for air defense, the advantages of the impulse method for locating aerial targets and the idea of ​​a panoramic station that simultaneously determines the distance and angle of a missile in the "Zeitschrift der Luftverteidigung", issue 2/1934.

In 1934, extensive work began on realizing radio location using continuous wave radiation . In August 1934 the experimental setup “Rapid” was tried out, which consisted of a 200 W transmitter on a wavelength of 4.7 m and two receiving systems set up 50 and 70 km apart. The passage of an aircraft at an altitude of 5200 m could be reliably registered on the basis of the beats formed by the interference of direct and reflected waves (“radar spirit”). This later resulted in the "Rewen" system, which was adopted in 1939 as RUS-1 (radioulowitel samoljotow) in the equipment of the Red Army. At the beginning of the war in 1941, 41 RUS-1 equipment sets were used in the air defense of Moscow and Leningrad.

At the beginning of 1935, work began in the Physico-Technical Institute of the Academy of Sciences under the direction of J. B. Kobsarew, which led to the construction of the first Soviet impulse radio measuring station. In the same year, proof was provided that a pulse radar on a wavelength of 4 m can reach a detection distance of 100 km. Successful experiments with Uda Yagi antennas followed and the development of special pulse transmitter tubes (IG-7, IG-8). By 1939 the mobile pulse radio measuring station “Redoute” was built, which was taken over into the equipment as RUS-2 after successful troop trials in July 1940 . In its original version, the RUS-2 consisted of a rotatable cabin with the 50 kW transmitter and the transmitting antenna on a ZIS-6 motor vehicle , a cabin with a receiving antenna, receiving equipment and a cathode ray tube as a viewing device on a GAZ-3A motor vehicle as well as a power supply unit on the bunk of another GAZ-3A. The antennas, which were similar for transmission and reception and moved synchronously, consisted of an active radiator, a reflector and five directors for the wavelength of 4 m. With the implementation of sending and receiving with only one antenna by means of an antenna switch, the entire apparatus could be accommodated on one vehicle and the rotation could be restricted to the antenna. By the start of the war in 1941, 15 devices of the single antenna variant had been delivered.

The RUS-2 made it possible to discover aerial targets at great distances and at all heights flown at that time and to determine their distance and their azimuth , the approximate speed and the number of aircraft groups (based on the interference), as well as the representation of the air situation in radius to 100 km. She played a major role in the air defense of Moscow and Leningrad. In 1943 a friend-foe identification device and a height measuring attachment based on the goniometer method were installed . Between 1940 and 1945 , 607  RUS-2s were delivered in different variants, including a single antenna variant in RUS-2s ("pegmatite") transport boxes. The pulse radio measuring station RUS-2 was the starting point for the development of several generations of mobile and stationary meter wave radio measuring devices in the Soviet Union ( P-3 , P-10, P-12 , P-18 , P-14, Oborona -14, Njebo).

The first Soviet decimeter wave system was built in 1935 under the direction of BK Schembel in the Central Radio Laboratory. Two 2 m mirrors, one each for transmitting and receiving at wavelengths from 21 to 29 cm, were arranged next to each other on a platform. With an emitted power of 8 to 15 W and a receiver sensitivity of 100 µV, an aircraft was discovered 8 km away. During tests in the Crimea, the reflection from mountains 100 km away could be observed and frequency modulation was used for the first time to measure distances .

In 1937, the method of the same signal zone by means of a rotating dipole was introduced for more precise determination of the angular coordinates (known today as the minimum bearing ). In the following years work was carried out on the creation of an aiming device for anti-aircraft guns in Leningrad and Kharkov. This resulted in a whole series of different magnetrons for the decimeter and centimeter wave range. In 1940 Degtarjow invented the reflex klystron , which was needed in the receiver.

The construction of a radio measurement complex for the flak was practically completed in 1940. The complex consisted of a continuous wave device for determining the angular coordinates on the 15 cm wavelength with 20 W power and a pulse device for distance measurement on the 80 cm wavelength with 15 kW pulse power. Due to the evacuation of the company in autumn 1941, however, series production did not start; some experimental devices were used in the air defense of Moscow and Leningrad.

Work on creating a radar for fighter planes began in 1940. In the experimental device "Gneis-1", a klystron with a wavelength of 15-16 cm was used in the transmitter , but this could no longer be produced due to the effects of the war. Therefore, under the direction of WW Tichomirow, the radio measuring device Gneis-2 was developed for use in twin-engine aircraft of the Pe-2 type with a tube transmitter with a wavelength of 1.5 m and a distance of 4 km. The first test samples passed their practical test in December 1942 near Stalingrad. It was accepted into the armament in 1943.

After the war, the strong expansion of civil air traffic also meant an increasing importance of air surveillance and, associated with this, a constant further development of on- board radar . The military sector was characterized by the arms race between the superpowers USA and USSR; the development of combat aircraft was accelerated. Higher speeds, and since the 1980s also fast, low-flying guided missiles and cruise missiles, demanded ever more powerful, far-reaching and accurate on-board radar systems. Radar was also increasingly used for target control in missiles, for the first time with the Bomarc surface-to-air guided missile .

Research after World War II

In Germany, research in the field of radar came to a complete standstill after the war. The Allies banned this until 1950. The research made considerable progress in the period that followed, particularly in the USA, where numerous new theoretical approaches and innovative components such as semiconductors and microprocessors were developed. The Synthetic Aperture Radar from 1951 is an example .

From 1950 onwards, German companies exclusively built British radars for civil airspace surveillance on a license basis. From then on, radar research in Europe was mainly characterized by numerous international collaborations.

Research in the field of on-board radars was also continued in the post-war period; a representative of the analog on-board radars is the NASARR model , which was used in the F-104 Starfighter and was built between 1961 and 1966. This was followed by the digital multifunction radar, which is still being developed today. For example, the EuroRADAR CAPTOR has been built since the early 1990s and is constantly being adapted to the current state of research.

Another milestone in the performance of radar systems was the use of antennas with electronic beam steering ( phased array antenna ). From around 1970, over-the-horizon radars and high-frequency radar search heads for end-phase guided ammunition were also used in the military.

Civil use

On-board radars are also standard equipment on board civil aircraft and ships. One of the first and to this day most important civil applications is the monitoring of air traffic using Air Traffic Control (ATC). A predecessor is the Ground Radar System , which Telefunken developed between 1955 and 1957.

The first distance warning radar systems for the automotive sector were developed as early as the late 1970s. In 1995, the Japanese car manufacturer Mitsubishi used an adaptive cruise control (ACC) as standard for the first time . In the 2000s, other car manufacturers followed suit and ensured widespread use. Radar systems are also used in vehicles as a parking aid and blind spot warning system. Another application of radar technology in road traffic is the measurement of excessive speeding by the police.

Radar technology has been used in space travel since the mid-1990s, primarily to measure the earth and other planets. Weather radars are also used to collect weather data .

In industry, radar sensors are used for motion detection or level measurement .

In geology , soil science , archeology , geotechnics , etc., geo or ground radar is used as an indirect geophysical investigation method.

literature

  • Cajus Bekker : eyes through night and fog. The radar story . 2nd improved edition. Stalling Verlag, Oldenburg u. a. 1964.
  • Robert Buderi: The Invention that Changed the World. How a Small Group of Radar Pioneers Won the Second World War and Launched a Technological Revolution . Simon & Schuster Ltd., New York NY 1996, ISBN 0-684-81021-2 ( Sloan technology series ).
  • Brian Johnson: Top Secret. Science and technology in World War II. Secret archives evaluated for the first time . Special edition. Weltbild, Augsburg 1994, ISBN 3-89350-818-X .
  • Ulrich Kern: The development of the radar method. On the history of radar technology up to 1945. Dissertation, Stuttgart 1984.
  • Harry von Kroge: GEMA-Berlin. Birthplace of German active waterborne sound and radio location technology. Self-published, Hamburg 1998, ISBN 3-00-002865-X .
  • MM Lobanow: Nachalo Sovetskoy Radiolokatsii (German: 'The beginnings of Soviet radio measurement technology'). Sovetskoye Radio Publishing House, Moscow 1975.
  • Robert M. Page: The Early History of Radar . Proceedings of the IRE (1962) Vol. 50, Issue 5, 1232-1236
  • David E. Pritchard : Through space and time. Radar development and use 1904–1945. Stuttgart 1992.
  • Frank Reuter: Radio measurement. The development and use of the RADAR process in Germany up to the end of the Second World War. Westdeutscher Verlag, Opladen 1971, ( Scientific papers of the Working Group for Research of the State of North Rhine-Westphalia 42, ISSN  0570-5665 ).
  • Harald Rockstuhl : Soviet radar station near Eigenrieden in Hainich in Thuringia 1983–1995 . Rockstuhl, Bad Langensalza 2006, ISBN 3-937135-79-0 .
  • Albert Sammt : My life for the zeppelin . 2nd Edition. With a contribution by Ernst Breuning. Edited and supplemented by Wolfgang von Zeppelin and Peter Kleinhans. Pestalozzi Kinderdorf, Wahlwies 1989, ISBN 3-921583-02-0 .
  • Fritz Trenkle : The German radio measurement methods until 1945 . Hüthig, Heidelberg 1987, ISBN 3-7785-1400-8 .
  • W.-R. Stuppert and S. Fiedler, The radio technical troops of the air defense of the GDR - history and stories , Steffen Verlag Berlin u. Friedland, 1st edition 2012, ISBN 978-3-942477-39-0

Web links

Commons : Radar  album with pictures, videos and audio files

Individual evidence

  1. ↑ Patent DE165546 : Method to report metallic objects to an observer by means of electrical waves. Registered April 30, 1904 , published November 21, 1905 . ‌
  2. ↑ Patent DE169154 : Method for determining the distance from metallic objects (ships or the like), the presence of which is determined by the method according to patent 165546. Registered November 11, 1904 , published April 2, 1906 . ‌
  3. ↑ http://www.uboat.net/allies/aircraft/wellington.htm
  4. ↑ see this frequency analysis
  5. ↑ PRECURSORS TO RADAR - THE WATSON-WATT MEMORANDUM AND THE DAVENTRY EXPERIMENT ( Memento of the original from May 25, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.bawdseyradar.org.uk
  6. ↑ A Brief History of Radar in the Soviet Union and Russia (PDF)