227:
1641:
981:
884:. Non-Doppler radar systems cannot be pointed directly at the ground due to excessive false alarms, which overwhelm computers and operators. Sensitivity must be reduced near clutter to avoid overload. This vulnerability begins in the low-elevation region several beam widths above the horizon, and extends downward. This also exists throughout the volume of moving air associated with weather phenomenon.
31:
1538:
194:
847:
1215:
684:
Rejection speed is selectable on pulse-Doppler aircraft-detection systems so nothing below that speed will be detected. A one degree antenna beam illuminates millions of square feet of terrain at 10 miles (16 km) range, and this produces thousands of detections at or below the horizon if
Doppler
1373:
Mechanical RF components, such as wave-guide, can produce
Doppler modulation due to phase shift induced by vibration. This introduces a requirement to perform full spectrum operational tests using shake tables that can produce high power mechanical vibration across all anticipated audio frequencies.
876:
generally appears in a circular region within a radius of about 25 miles (40 km) near ground-based radar. This distance extends much further in airborne and space radar. Clutter results from radio energy being reflected from the earth surface, buildings, and vegetation. Clutter includes weather
688:
Pulse-Doppler radar uses the following signal processing criteria to exclude unwanted signals from slow-moving objects. This is also known as clutter rejection. Rejection velocity is usually set just above the prevailing wind speed (10 to 100 mph or 20 to 160 km/h). The velocity threshold
73:
starting in the 1960s. Earlier radars had used pulse-timing in order to determine range and the angle of the antenna (or similar means) to determine the bearing. However, this only worked when the radar antenna was not pointed down; in that case the reflection off the ground overwhelmed any returns
1381:
antenna. This is because the phase-shifter elements in the antenna are non-reciprocal and the phase shift must be adjusted before and after each transmit pulse. Spurious phase shift is produced by the sudden impulse of the phase shift, and settling during the receive period between transmit pulses
1257:
Tracking radar systems use angle error to improve accuracy by producing measurements perpendicular to the radar antenna beam. Angular measurements are averaged over a span of time and combined with radial movement to develop information suitable to predict target position for a short time into the
2135:
A helicopter appears like a rapidly pulsing noise emitter except in a clear environment free from clutter. An audible signal is produced for passive identification of the type of airborne object. Microwave
Doppler frequency shift produced by reflector motion falls into the audible sound range for
1025:
Search radar that include pulse-Doppler are usually dual mode because best overall performance is achieved when pulse-Doppler is used for areas with high false alarm rates (horizon or below and weather), while conventional radar will scan faster in free-space where false alarm rate is low (above
757:
1636:{\displaystyle {\text{dynamic range}}=\min {\begin{cases}{\tfrac {\text{carrier power}}{\text{noise power}}}&{\text{transmit noise, where bandwidth is }}{\tfrac {\text{PRF}}{\text{filter size}}}\\2^{{\text{sample bits}}+{\text{filter size}}}&{\text{receiver dynamic range}}\end{cases}}.}
1245:
Range and velocity cannot be measured directly using medium PRF, and ambiguity resolution is required to identify true range and speed. Doppler signals are generally above 1 kHz, which is audible, so audio signals from medium-PRF systems can be used for passive target classification.
1346:
is adjusted to smooth the leading edge and trailing edge so that RF power is increased and decreased without an abrupt change. This creates a transmit pulse with smooth ends instead of a square wave, which reduces ringing phenomenon that is otherwise associated with target reflection.
1730:
The pulse-Doppler radar equation can be used to understand trade-offs between different design constraints, like power consumption, detection range, and microwave safety hazards. This is a very simple form of modeling that allows performance to be evaluated in a sterile environment.
764:
1860:
1139:
292:
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1010:
Pulse-Doppler radar by itself can be too slow to cover the entire volume of space above the horizon unless fan beam is used. This approach is used with the AN/SPS 49(V)5 Very Long Range Air
Surveillance Radar, which sacrifices elevation measurement to gain speed.
105:, they are used for discriminating aircraft from clutter. Besides the above conventional surveillance applications, pulse-Doppler radar has been successfully applied in healthcare, such as fall risk assessment and fall detection, for nursing or clinical purposes.
1507:
from mountains, buildings or wave tops can be used to detect fast moving objects otherwise blocked by solid obstruction along the line of sight. This is a very lossy phenomenon that only becomes possible when radar has significant excess sub-clutter visibility.
1681:
2010:
system with 1024 elements provides 30.103 dB of improvement due to the type of signal processing that must be used with pulse-Doppler radar. The energy of all of the individual pulses from the object are added together by the filtering process.
926:(MTI) provide up to 25 dB sub-clutter visibility. An MTI antenna beam is aimed above the horizon to avoid an excessive false alarm rate, which renders systems vulnerable. Aircraft and some missiles exploit this weakness using a technique called
1721:
1154:
2165:
Once in track mode, pulse-Doppler radar must include a way to modify
Doppler filtering for the volume of space surrounding a track when radial velocity falls below the minimum detection velocity. Doppler filter adjustment must be linked with a
1386:
for sub-clutter visibility. Phase shifter settling time on the order of 50ns is required. Start of receiver sampling needs to be postponed at least 1 phase-shifter settling time-constant (or more) for each 20 dB of sub-clutter visibility.
696:
651:
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74:
from other objects. As the ground moves at the same speed but opposite direction of the aircraft, Doppler techniques allow the ground return to be filtered out, revealing aircraft and vehicles. This gives pulse-Doppler radars "
1047:
The signal processing enhancement of pulse-Doppler allows small high-speed objects to be detected in close proximity to large slow moving reflectors. To achieve this, the transmitter must be coherent and should produce low
1999:
Detection range is increased proportional to the fourth root of the number of filters for a given power consumption. Alternatively, power consumption is reduced by the number of filters for a given detection range.
1088:
582:
241:
1320:
Scalloping for pulse-Doppler radar involves blind velocities created by the clutter rejection filter. Every volume of space must be scanned using 3 or more different PRF. A two PRF detection scheme will have
316:
113:
The earliest radar systems failed to operate as expected. The reason was traced to
Doppler effects that degrade performance of systems not designed to account for moving objects. Fast-moving objects cause a
1390:
Most antenna phase shifters operating at PRF above 1 kHz introduce spurious phase shift unless special provisions are made, such as reducing phase shifter settling time to a few dozen nanoseconds.
1740:
1648:
1535:
Subclutter visibility involves the maximum ratio of clutter power to target power, which is proportional to dynamic range. This determines performance in heavy weather and near the earth surface.
2173:
Tracking will cease without this feature because the target signal will otherwise be rejected by the
Doppler filter when radial velocity approaches zero because there is no change in frequency.
1014:
Pulse-Doppler antenna motion must be slow enough so that all the return signals from at least 3 different PRFs can be processed out to the maximum anticipated detection range. This is known as
842:{\displaystyle \left\vert {\frac {{\text{Doppler frequency}}\times C}{2\times {\text{transmit frequency}}}}-{\text{ground speed}}\times \cos \Theta \right\vert >{\text{velocity threshold}},}
214:
Pulse-Doppler systems measure the range to objects by measuring the elapsed time between sending a pulse of radio energy and receiving a reflection of the object. Radio waves travel at the
1688:
916:
capability, and pulse-Doppler is the only strategy that can satisfy this requirement. This eliminates vulnerabilities associated with the low-elevation and below-horizon environment.
2151:
A special mode is required because the
Doppler velocity feedback information must be unlinked from radial movement so that the system can transition from scan to track with no lock.
2014:
Signal processing for a 1024-point filter improves performance by 30.103 dB, assuming compatible transmitter and antenna. This corresponds to 562% increase in maximal distance.
1143:
In addition to this sampling limit, the duration of the transmitted pulse could mean that returns from two targets will be received simultaneously from different parts of the pulse.
2116:
sound for the operator in track mode on some radar systems. The operator uses this sound for passive target classification, such as recognizing helicopters and electronic jamming.
1354:
that minimizes ringing that occurs any time pulses are applied to a filter. In a digital system, this adjusts the phase and/or amplitude of each sample before it is applied to the
2293:
Tactical missile aerodynamics, Volume 141. P17. Michael J. Hemsch, American
Institute of Aeronautics and Astronautics. American Institute of Aeronautics and Astronautics, 1992
2714:
593:
674:
1317:
Pulse-Doppler signal processing introduces a phenomenon called scalloping. The name is associated with a series of holes that are scooped-out of the detection performance.
1401:
1254:
Radar systems require angular measurement. Transponders are not normally associated with pulse-Doppler radar, so sidelobe suppression is required for practical operation.
1151:
The velocity resolution is the minimal radial velocity difference between two objects traveling at the same range before the radar can detect two discrete reflections:
525:
500:
78:" capability. A secondary advantage in military radar is to reduce the transmitted power while achieving acceptable performance for improved safety of stealthy radar.
867:
991:
Scan time is a critical factor for some systems because vehicles moving at or above the speed of sound can travel one mile (1.6 km) every few seconds, like the
478:
1295:
are not appropriate because noise introduced by these devices interfere with detection performance. The only amplification devices suitable for pulse-Doppler are
69:
engines, and which was armed with a W40 nuclear weapon to destroy entire formations of attacking enemy aircraft. Pulse-Doppler systems were first widely used on
1210:{\displaystyle {\text{velocity resolution}}={\frac {C\times {\text{PRF}}}{2\times {\text{transmit frequency}}\times {\text{filter size in transmit pulses}}}}.}
2148:
used for that purpose, like A-scope, B-scope, C-scope, and RHI indicator. The human ear may be able to tell the difference better than electronic equipment.
1085:
The range resolution is the minimal range separation between two objects traveling at the same speed before the radar can detect two discrete reflections:
2101:
selectively excludes low-velocity reflections so that no detections occurs below a threshold velocity. This eliminates terrain, weather, biologicals, and
752:{\displaystyle \left\vert {\frac {{\text{Doppler frequency}}\times C}{2\times {\text{transmit frequency}}}}\right\vert >{\text{velocity threshold}}.}
534:
1007:. The maximum time to scan the entire volume of the sky must be on the order of a dozen seconds or less for systems operating in that environment.
2238:
1503:
Choppy surfaces, like waves and trees, form a diffraction grating suitable for bending microwave signals. Pulse-Doppler can be so sensitive that
2626:
1029:
The antenna type is an important consideration for multi-mode radar because undesirable phase shift introduced by the radar antenna can degrade
586:
This allows the radar to separate the reflections from multiple objects located in the same volume of space by separating the objects using a
2552:
2342:
1685:
A small fast-moving target reflection can be detected in the presence of larger slow-moving clutter reflections when the following is true:
163:
2154:
Similar techniques are required to develop track information for jamming signals and interference that cannot satisfy the lock criterion.
181:
It became possible to use pulse-Doppler radar on aircraft after digital computers were incorporated in the design. Pulse-Doppler provided
2400:
2456:
1523:
uses variable density in the air column above the surface of the earth to bend RF signals. An inversion layer can produce a transient
152:, but more sophisticated techniques were developed that record the phase of each transmitted pulse for comparison to returned echoes.
148:, and solid state devices. Early pulse-dopplers were incompatible with other high power microwave amplification devices that are not
2664:
2548:
2506:
2273:
2262:
1239:
2375:
2689:
1855:{\displaystyle R=\left({\frac {P_{\text{t}}G_{\text{t}}A_{\text{r}}\sigma FD}{16\pi ^{2}k_{\text{B}}TBN}}\right)^{\frac {1}{4}},}
891:
Allows the radar antenna to be pointed directly at the ground without overwhelming the computer and without reducing sensitivity.
207:
159:
B developed during the 1950s specifically for the purpose of operating in hurricane conditions with no performance degradation.
2704:
2167:
2098:
2070:
2055:
indicates the difference between the two measurements is below a threshold, which can only occur with an object that satisfies
2007:
2003:
1989:
1134:{\displaystyle {\text{range resolution}}={\frac {C}{{\text{PRF}}\times ({\text{number of samples between transmit pulses}})}}.}
1042:
299:
is essential for pulse-Doppler radar operation. As the reflector moves between each transmit pulse, the returned signal has a
2694:
1074:
2431:
1362:
is the most effective because it produces a flat processing floor with no ringing that would otherwise cause false alarms.
287:{\displaystyle {\text{Doppler frequency}}={\frac {2\times {\text{transmit frequency}}\times {\text{radial velocity}}}{C}}.}
2699:
1959:
443:{\displaystyle I=I_{0}\sin \left({\frac {4\pi (x_{0}+v\Delta t)}{\lambda }}\right)=I_{0}\sin(\Theta _{0}+\Delta \Theta ),}
2719:
2709:
2189:
945:
895:
881:
167:
2520:
984:
Maximum range from reflectivity (red) and unambiguous
Doppler velocity range (blue) with a fixed pulse repetition rate.
761:
In airborne pulse-Doppler radar, the velocity threshold is offset by the speed of the aircraft relative to the ground.
218:, so the distance to the object is the elapsed time multiplied by the speed of light, divided by two โ there and back.
2102:
2077:
2036:
Scan mode involves frequency filtering, amplitude thresholding, and ambiguity resolution. Once a reflection has been
2044:, the pulse-Doppler radar automatically transitions to tracking mode for the volume of space surrounding the track.
988:
Ambiguity processing is required when target range is above the red line in the graphic, which increases scan time.
2124:
Special consideration is required for aircraft with large moving parts because pulse-Doppler radar operates like a
1645:
Subclutter visibility is the ratio of the smallest signal that can be detected in the presence of a larger signal.
1233:
1067:
953:
137:
2242:
2037:
956:(PRF) reflected microwave signals fall between 1,500 and 15,000 cycle per second, which is audible. This means a
129:
and moving target indicator radar, which can mask aircraft reflections. This phenomenon was adapted for use with
2177:
1676:{\displaystyle {\text{subclutter visibility}}={\frac {\text{dynamic range}}{\text{CFAR detection threshold}}}.}
1019:
902:
90:
50:
of the returned signal to determine the target object's velocity. It combines the features of pulse radars and
2006:
integrates all of the energy from all of the individual reflected pulses that enter the filter. This means a
1292:
1030:
923:
119:
1930:
1520:
1383:
1355:
1242:(PRF) from about 3 kHz to 30 kHz. The range between transmit pulses is 5 km to 50 km.
949:
1524:
2207:
307:, from pulse to pulse. This causes the reflector to produce Doppler modulation on the reflected signal.
51:
2327:
Proceedings of the 5th International ICST Conference on Pervasive Computing Technologies for Healthcare
1224:
Pulse-Doppler radar has special requirements that must be satisfied to achieve acceptable performance.
1716:{\displaystyle {\text{target power}}>{\frac {\text{clutter power}}{\text{subclutter visibility}}}.}
118:
on the transmit pulse that can produce signal cancellation. Doppler has maximum detrimental effect on
2633:
2321:
Liang, Liu; Popescu, Mihail; Skubic, Marjorie; Rantz, Marilyn; Yardibi, Tarik; Cuddihy, Paul (2011).
2041:
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75:
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capability to support air-to-air missile systems in most modern military aircraft by the mid 1970s.
2602:
2581:
2577:
2406:. National Oceanic and Atmospheric Administration, National Severe Storm Laboratory. Archived from
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2056:
1993:
1981:
1910:
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1343:
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1278:
149:
145:
102:
2170:
to automatically adjust Doppler rejection speed within the volume of space surrounding the track.
2059:. Other types of electronic signals cannot produce a lock. Lock exists in no other type of radar.
1370:
Pulse-Doppler radar is generally limited to mechanically aimed antennas and active phased arrays.
2348:
2247:
2225:
1943:
1891:
1495:
The antenna type and scan performance is a practical consideration for multi-mode radar systems.
1395:
1015:
1004:
965:
2128:. Blade tips moving near the speed of sound produce the only signal that can be detected when a
1285:
reduces sub-clutter visibility performance by producing apparent motion on stationary objects.
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2502:
2338:
2269:
2258:
2125:
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2407:
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1312:
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238:, where movement in range produces frequency shift on the signal reflected from the target.
136:
Pulse-Doppler radar was developed during World War II to overcome limitations by increasing
89:
from the velocity of any precipitation in the air. Pulse-Doppler radar is also the basis of
70:
2460:
2162:
Pulse-Doppler radar must be multi-mode to handle aircraft turning and crossing trajectory.
1984:
and accounting for in-band noise distribution across multiple detection filters. The value
456:
1351:
1262:
972:
produce a tone. The actual size of the target can be calculated using the audible signal.
909:
587:
296:
94:
2556:
2017:
These improvements are the reason pulse-Doppler is essential for military and astronomy.
46:
system that determines the range to a target using pulse-timing techniques, and uses the
2379:
2303:
1382:
places Doppler modulation onto stationary clutter. That receive modulation corrupts the
1336:
pose a problem with search, detection, and ambiguity resolution in pulse-Doppler radar.
646:{\displaystyle v={\text{target speed}}={\frac {\lambda \Delta \Theta }{4\pi \Delta t}},}
2684:
235:
215:
171:
98:
47:
2076:
Lock eliminates the need for human intervention with the exception of helicopters and
1066:
The received signals from multiple PRF are compared to determine true range using the
980:
122:
systems, which must use reverse phase shift for Doppler compensation in the detector.
2678:
2201:
2195:
2145:
1455:{\displaystyle T={\frac {1}{e^{\frac {\text{SCV}}{20}}\times S\times {\text{PRF}}}},}
1053:
869:
is the angle offset between the antenna position and the aircraft flight trajectory.
690:
300:
130:
115:
82:
62:
2352:
2144:), which is used for target classification in addition to the kinds of conventional
2401:"Path to Nexrad, Doppler Radar Development at the National Severe Storm Laboratory"
1969:
1920:
1378:
961:
2534:
2051:, where Doppler velocity is compared with the range movement on successive scans.
313:
The amplitude of the successively returning pulse from the same scanned volume is
944:
Audible Doppler and target size support passive vehicle type classification when
2435:
2213:
2113:
1504:
1282:
1049:
55:
2322:
2129:
1516:
1052:
during the detection interval, and the receiver must have large instantaneous
957:
86:
30:
17:
156:
937:
Pulse-Doppler provides an advantage when attempting to detect missiles and
2228:- velocity measurements in medical ultrasound. Based on the same principle
1515:
or lower to extend the horizon, which is very different from diffraction.
193:
2378:. IEEE New Hampshire Section, University of New Hampshire. Archived from
2307:
2219:
2088:
1296:
141:
170:
interceptor aircraft for the United States Air Force, and later for the
2176:
Multi-mode operation may also include continuous wave illumination for
1476:
1325:
with a pattern of discrete ranges, each of which has a blind velocity.
1394:
The following gives the maximum permissible settling time for antenna
1512:
992:
934:). This flying technique is ineffective against pulse-Doppler radar.
310:
Pulse-Doppler radars exploit this phenomenon to improve performance.
66:
2657:
X-Fighters: USAF Experimental and Prototype Fighters, XP-59 to YF-23
206:
125:
Doppler weather effects (precipitation) were also found to degrade
2323:"Automatic fall detection based on Doppler radar motion signature"
1988:
is added to the standard radar range equation to account for both
1977:
1018:. Antenna motion for pulse-Doppler must be as slow as radar using
1000:
979:
577:{\displaystyle \Delta \Theta ={\frac {4\pi v\Delta t}{\lambda }}.}
205:
192:
166:
was a prototype airborne radar/combination system for the planned
133:
in the 1950s after declassification of some World War II systems.
126:
43:
2268:
Advanced Radar Techniques and Systems edited by Gaspare Galati (
2095:, so the lock criterion is not normally used for weather radar.
1527:
that traps RF signals in a thin layer of air like a wave-guide.
877:
in radar intended to detect and report aircraft and spacecraft.
2108:
The target Doppler signal from the detection is converted from
2376:"Clutter Rejection (Pulse Doppler), Radar Systems Engineering"
2483:"Powerofpulse.com - North American Economic and Health Site"
2482:
1261:
The two angle error techniques used with tracking radar are
54:, which were formerly separate due to the complexity of the
2241:
presentation, which highlights the advantages of using the
2216:(non-pulsed, swept frequency, range and Doppler processing)
1626:
1350:
Second, the shape of the receive pulse is adjusted using a
901:
Increases detection range by 300% or more in comparison to
2025:
Pulse-Doppler radar for aircraft detection has two modes.
1377:
Doppler is incompatible with most electronically steered
65:, an American long range supersonic missile powered by
1581:
1562:
1485:= number of range samples between each transmit pulse,
1903:= effective aperture (area) of the receiving antenna,
1743:
1691:
1651:
1541:
1404:
1157:
1091:
855:
767:
699:
659:
596:
537:
510:
488:
459:
319:
244:
174:. The US's first pulse-Doppler radar, the system had
81:
Pulse-Doppler techniques also find widespread use in
61:
The first operational pulse-Doppler radar was in the
2252:
Introduction to Principles and Applications of Radar
898:
for small object detection near terrain and weather.
230:
Change of wavelength caused by motion of the source
2503:"AN/SPS-49 Very Long-Range Air Surveillance Radar"
1854:
1715:
1675:
1635:
1454:
1209:
1133:
894:Fills in the vulnerability region associated with
861:
841:
751:
668:
645:
576:
519:
494:
472:
442:
286:
2659:. St. Paul, Minnesota: Motorbooks International.
1734:The theoretical range performance is as follows.
1511:Refraction and ducting use transmit frequency at
1073:The received signals are also compared using the
178:capability and could track one target at a time.
1550:
872:Surface reflections appear in almost all radar.
155:Early examples of military systems includes the
2066:needs to be satisfied during normal operation.
1929:= Doppler filter size (transmit pulses in each
941:flying near terrain, sea surface, and weather.
2457:"Subclutter Visibility and Improvement Factor"
2434:. Weather Beacon Doppler Radar. Archived from
1059:Pulse-Doppler signal processing also includes
887:Pulse-Doppler radar corrects this as follows.
2222:- the reason for ambiguous velocity estimates
8:
1491:= maximal design pulse repetition frequency.
676:is the phase shift induced by range motion.
2071:Pulse-Doppler signal processing ยง Lock
1913:, or scattering coefficient, of the target,
2715:Science and technology during World War II
1976:This equation is derived by combining the
905:(MTI) by improving sub-clutter visibility.
880:Clutter creates a vulnerability region in
2198:(non-pulsed; used for navigation systems)
2132:is moving slow near terrain and weather.
1838:
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1119:number of samples between transmit pulses
1117:
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1092:
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2335:10.4108/icst.pervasivehealth.2011.245993
1577:transmit noise, where bandwidth is
225:
29:
2286:
2257:Modern Radar Systems by Hamish Meikle (
140:. This required the development of the
2603:"High Power L Band Fast Phase Shifter"
2105:with the exception of decoy aircraft.
2553:Massachusetts Institute of Technology
2210:(non-pulsed, pure Doppler processing)
1960:receiver bandwidth (band-pass filter)
1063:to identify true range and velocity.
7:
234:Pulse-Doppler radar is based on the
164:Hughes AN/ASG-18 Fire Control System
34:Airborne pulse-Doppler radar antenna
2632:. Norhrop Grummond. Archived from
2192:(fundamentals of the radar signal)
1921:antenna pattern propagation factor
912:of about 60 dB is needed for
856:
820:
663:
660:
631:
620:
617:
559:
541:
538:
511:
431:
428:
416:
374:
85:, allowing the radar to determine
25:
2507:Federation of American Scientists
2304:"AN/APQ-174/186 Multi-Mode Radar"
1240:medium pulse repetition frequency
896:pulse-amplitude time-domain radar
882:pulse-amplitude time-domain radar
2204:(pulsed with Doppler processing)
1339:Ringing is reduced in two ways.
590:to segregate different signals:
480:is the distance radar to target,
197:Principle of pulse-Doppler radar
2099:Pulse-Doppler signal processing
2008:pulse-Doppler signal processing
2004:Pulse-Doppler signal processing
1990:pulse-Doppler signal processing
1277:Pulse-Doppler radar requires a
1043:Pulse-Doppler signal processing
527:is the time between two pulses.
2521:"Dwell Time and Hits Per Scan"
2432:"How does Doppler Radar Work?"
1994:transmitter FM noise reduction
1469:= phase shifter settling time,
1198:filter size in transmit pulses
1122:
1114:
1075:frequency ambiguity resolution
669:{\displaystyle \Delta \Theta }
434:
412:
380:
355:
1:
1238:Pulse-Doppler typically uses
970:Aircraft with no moving parts
2254:course at University of Iowa
2190:Radar signal characteristics
1894:of the transmitting antenna,
1475:= sub-clutter visibility in
1033:for sub-clutter visibility.
960:sounds like a helicopter, a
946:identification friend or foe
910:Clutter rejection capability
168:North American XF-108 Rapier
1344:shape of the transmit pulse
1303:, and solid state devices.
1026:horizon with clear skies).
2736:
2627:"AWACS Surveillance Radar"
1310:
1234:Pulse repetition frequency
1231:
1228:Pulse repetition frequency
1068:range ambiguity resolution
1040:
954:pulse repetition frequency
939:low observability aircraft
138:pulse repetition frequency
2243:autocorrelation technique
1872:= distance to the target,
210:Principle of pulsed radar
2578:"Dolph-Chebyshev Window"
2329:. IEEE PervasiveHealth.
2178:semi-active radar homing
2083:Weather phenomenon obey
2047:Track mode works like a
1666:CFAR detection threshold
1281:with very little noise.
1031:performance measurements
948:is not available from a
903:moving target indication
520:{\displaystyle \Delta t}
502:is the radar wavelength,
495:{\displaystyle \lambda }
91:synthetic aperture radar
2690:Radar signal processing
2549:"Side Lobe Suppression"
2535:"Side Lobe Suppression"
2365:Pace 1991, p. 152.
1952:= absolute temperature,
1293:crossed-field amplifier
968:sound like propellers.
964:sounds like a jet, and
924:moving target indicator
862:{\displaystyle \Theta }
120:moving target indicator
2705:Navigational equipment
2021:Aircraft tracking uses
1931:Fast Fourier transform
1856:
1717:
1677:
1637:
1620:receiver dynamic range
1521:over-the-horizon radar
1456:
1384:measure of performance
1360:Dolph-Chebyshev window
1356:fast Fourier transform
1211:
1135:
985:
928:flying below the radar
863:
843:
753:
670:
647:
578:
521:
496:
474:
444:
288:
231:
211:
198:
52:continuous-wave radars
35:
2695:Measuring instruments
2208:Continuous-wave radar
1857:
1718:
1706:subclutter visibility
1678:
1654:subclutter visibility
1638:
1531:Subclutter visibility
1457:
1220:Special consideration
1212:
1136:
983:
864:
844:
754:
671:
648:
579:
522:
497:
475:
473:{\displaystyle x_{0}}
445:
289:
229:
209:
196:
83:meteorological radars
33:
2700:Microwave technology
2655:Pace, Steve (1991).
2168:radar track function
1881:= transmitter power,
1741:
1689:
1649:
1539:
1402:
1155:
1089:
1061:ambiguity resolution
930:to avoid detection (
914:look-down/shoot-down
853:
765:
697:
657:
594:
535:
508:
486:
457:
317:
242:
222:Velocity measurement
183:look-down/shoot-down
176:look-down/shoot-down
76:look-down/shoot-down
27:Type of radar system
2720:Targeting (warfare)
2710:Air traffic control
2582:Stanford University
2537:. Radartutorial.eu.
2248:Pulse-Doppler radar
2093:Newtonian mechanics
2057:Newtonian mechanics
1911:radar cross section
1396:phase shift modules
1301:traveling wave tube
1279:coherent oscillator
1250:Angular measurement
1160:velocity resolution
1147:Velocity resolution
1005:air-to-air missiles
743:velocity threshold
146:traveling wave tube
103:air traffic control
40:pulse-Doppler radar
2463:on January 1, 2011
2226:Doppler sonography
2103:mechanical jamming
2078:electronic jamming
1944:Boltzmann constant
1852:
1713:
1673:
1633:
1625:
1590:
1571:
1452:
1207:
1190:transmit frequency
1131:
986:
966:propeller aircraft
950:transponder signal
859:
839:
833:velocity threshold
797:transmit frequency
749:
728:transmit frequency
689:is much lower for
666:
643:
574:
517:
492:
470:
440:
284:
264:transmit frequency
232:
212:
199:
127:conventional radar
36:
2344:978-1-936968-15-2
2126:phase-locked loop
2085:adiabatic process
2049:phase-locked loop
1846:
1832:
1819:
1785:
1775:
1765:
1708:
1707:
1704:
1695:
1668:
1667:
1664:
1655:
1621:
1612:
1604:
1589:
1588:
1585:
1578:
1570:
1569:
1566:
1545:
1447:
1444:
1429:
1425:
1334:Ringing artifacts
1202:
1199:
1191:
1178:
1161:
1126:
1120:
1109:
1095:
1037:Signal processing
920:Pulse compression
834:
809:
801:
798:
779:
778:Doppler frequency
744:
732:
729:
710:
709:Doppler frequency
638:
606:
569:
387:
279:
273:
265:
248:
247:Doppler frequency
202:Range measurement
16:(Redirected from
2727:
2670:
2641:
2640:
2638:
2631:
2623:
2617:
2616:
2614:
2612:
2607:
2599:
2593:
2592:
2590:
2588:
2574:
2568:
2567:
2565:
2564:
2555:. Archived from
2545:
2539:
2538:
2531:
2525:
2524:
2523:. Radartutorial.
2517:
2511:
2510:
2499:
2493:
2492:
2490:
2489:
2479:
2473:
2472:
2470:
2468:
2459:. Archived from
2453:
2447:
2446:
2444:
2443:
2428:
2422:
2421:
2419:
2418:
2412:
2405:
2397:
2391:
2390:
2388:
2387:
2372:
2366:
2363:
2357:
2356:
2318:
2312:
2311:
2300:
2294:
2291:
2143:
2141:
2110:frequency domain
2087:associated with
1861:
1859:
1858:
1853:
1848:
1847:
1839:
1837:
1833:
1831:
1821:
1820:
1817:
1811:
1810:
1797:
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1714:
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1610:
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1591:
1586:
1583:
1582:
1579:
1576:
1572:
1567:
1564:
1563:
1546:
1543:
1525:troposphere duct
1490:
1484:
1474:
1468:
1461:
1459:
1458:
1453:
1448:
1446:
1445:
1442:
1431:
1430:
1423:
1422:
1412:
1313:Radar scalloping
1289:Cavity magnetron
1216:
1214:
1213:
1208:
1203:
1201:
1200:
1197:
1192:
1189:
1180:
1179:
1176:
1167:
1162:
1159:
1140:
1138:
1137:
1132:
1127:
1125:
1121:
1118:
1110:
1107:
1101:
1096:
1094:range resolution
1093:
1081:Range resolution
932:nap-of-the-earth
868:
866:
865:
860:
848:
846:
845:
840:
835:
832:
827:
823:
810:
807:
802:
800:
799:
796:
787:
780:
777:
774:
758:
756:
755:
750:
745:
742:
737:
733:
731:
730:
727:
718:
711:
708:
705:
675:
673:
672:
667:
652:
650:
649:
644:
639:
637:
623:
612:
607:
604:
583:
581:
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575:
570:
565:
548:
526:
524:
523:
518:
501:
499:
498:
493:
479:
477:
476:
471:
469:
468:
449:
447:
446:
441:
424:
423:
405:
404:
392:
388:
383:
367:
366:
347:
335:
334:
293:
291:
290:
285:
280:
275:
274:
271:
266:
263:
254:
249:
246:
101:and mapping. In
71:fighter aircraft
21:
2735:
2734:
2730:
2729:
2728:
2726:
2725:
2724:
2675:
2674:
2673:
2667:
2654:
2650:
2645:
2644:
2636:
2629:
2625:
2624:
2620:
2610:
2608:
2605:
2601:
2600:
2596:
2586:
2584:
2576:
2575:
2571:
2562:
2560:
2547:
2546:
2542:
2533:
2532:
2528:
2519:
2518:
2514:
2501:
2500:
2496:
2487:
2485:
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2455:
2454:
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2441:
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2374:
2373:
2369:
2364:
2360:
2345:
2320:
2319:
2315:
2302:
2301:
2297:
2292:
2288:
2283:
2235:
2186:
2160:
2139:
2137:
2122:
2023:
1941:
1902:
1889:
1880:
1812:
1802:
1798:
1778:
1768:
1758:
1757:
1751:
1750:
1739:
1738:
1728:
1687:
1686:
1647:
1646:
1624:
1623:
1616:
1596:
1593:
1592:
1573:
1554:
1537:
1536:
1533:
1501:
1488:
1482:
1472:
1466:
1417:
1416:
1400:
1399:
1368:
1352:window function
1331:
1315:
1309:
1275:
1252:
1236:
1230:
1222:
1181:
1168:
1153:
1152:
1149:
1105:
1087:
1086:
1083:
1045:
1039:
978:
851:
850:
788:
775:
772:
768:
763:
762:
719:
706:
700:
695:
694:
682:
655:
654:
624:
613:
592:
591:
588:spread spectrum
549:
533:
532:
506:
505:
484:
483:
460:
455:
454:
415:
396:
358:
348:
342:
326:
315:
314:
303:difference, or
297:Radial velocity
272:radial velocity
255:
240:
239:
224:
204:
191:
111:
95:radar astronomy
28:
23:
22:
15:
12:
11:
5:
2733:
2731:
2723:
2722:
2717:
2712:
2707:
2702:
2697:
2692:
2687:
2677:
2676:
2672:
2671:
2665:
2651:
2649:
2646:
2643:
2642:
2639:on 2009-02-27.
2618:
2594:
2569:
2540:
2526:
2512:
2494:
2474:
2448:
2423:
2392:
2367:
2358:
2343:
2313:
2295:
2285:
2284:
2282:
2279:
2278:
2277:
2266:
2255:
2250:handouts from
2245:
2234:
2233:External links
2231:
2230:
2229:
2223:
2217:
2211:
2205:
2199:
2193:
2185:
2182:
2159:
2156:
2136:human beings (
2121:
2118:
2074:
2073:
2064:lock criterion
2034:
2033:
2030:
2022:
2019:
1982:noise equation
1978:radar equation
1974:
1973:
1963:
1953:
1947:
1939:
1934:
1924:
1914:
1904:
1900:
1895:
1887:
1882:
1878:
1873:
1863:
1862:
1851:
1845:
1842:
1836:
1830:
1827:
1824:
1815:
1809:
1805:
1801:
1796:
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1790:
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1771:
1761:
1754:
1749:
1746:
1727:
1724:
1712:
1699:
1672:
1659:
1632:
1627:
1617:
1608:
1599:
1595:
1594:
1574:
1560:
1559:
1557:
1552:
1549:
1532:
1529:
1500:
1497:
1493:
1492:
1486:
1480:
1470:
1451:
1440:
1437:
1434:
1428:
1420:
1415:
1410:
1407:
1367:
1364:
1330:
1327:
1323:detection gaps
1311:Main article:
1308:
1305:
1274:
1271:
1251:
1248:
1232:Main article:
1229:
1226:
1221:
1218:
1206:
1195:
1187:
1184:
1174:
1171:
1165:
1148:
1145:
1130:
1124:
1116:
1113:
1104:
1099:
1082:
1079:
1041:Main article:
1038:
1035:
977:
974:
907:
906:
899:
892:
874:Ground clutter
858:
838:
830:
826:
822:
819:
816:
813:
805:
794:
791:
786:
783:
771:
748:
740:
736:
725:
722:
717:
714:
703:
681:
678:
665:
662:
642:
636:
633:
630:
627:
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619:
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573:
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555:
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540:
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528:
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491:
481:
467:
463:
439:
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427:
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418:
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403:
399:
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379:
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365:
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351:
345:
341:
338:
333:
329:
325:
322:
283:
278:
269:
261:
258:
252:
236:Doppler effect
223:
220:
216:speed of light
203:
200:
190:
187:
172:Lockheed YF-12
110:
107:
99:remote sensing
48:Doppler effect
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
2732:
2721:
2718:
2716:
2713:
2711:
2708:
2706:
2703:
2701:
2698:
2696:
2693:
2691:
2688:
2686:
2683:
2682:
2680:
2668:
2666:0-87938-540-5
2662:
2658:
2653:
2652:
2647:
2635:
2628:
2622:
2619:
2604:
2598:
2595:
2583:
2579:
2573:
2570:
2559:on 2012-03-31
2558:
2554:
2550:
2544:
2541:
2536:
2530:
2527:
2522:
2516:
2513:
2508:
2504:
2498:
2495:
2484:
2478:
2475:
2462:
2458:
2452:
2449:
2438:on 2012-03-31
2437:
2433:
2427:
2424:
2413:on 2012-03-21
2409:
2402:
2396:
2393:
2382:on 2012-03-31
2381:
2377:
2371:
2368:
2362:
2359:
2354:
2350:
2346:
2340:
2336:
2332:
2328:
2324:
2317:
2314:
2309:
2305:
2299:
2296:
2290:
2287:
2280:
2275:
2274:0-86341-172-X
2271:
2267:
2264:
2263:1-58053-294-2
2260:
2256:
2253:
2249:
2246:
2244:
2240:
2239:Doppler radar
2237:
2236:
2232:
2227:
2224:
2221:
2218:
2215:
2212:
2209:
2206:
2203:
2202:Weather radar
2200:
2197:
2196:Doppler radar
2194:
2191:
2188:
2187:
2183:
2181:
2179:
2174:
2171:
2169:
2163:
2157:
2155:
2152:
2149:
2147:
2146:radar display
2133:
2131:
2127:
2119:
2117:
2115:
2111:
2106:
2104:
2100:
2096:
2094:
2090:
2086:
2081:
2079:
2072:
2069:
2068:
2067:
2065:
2060:
2058:
2054:
2050:
2045:
2043:
2039:
2031:
2028:
2027:
2026:
2020:
2018:
2015:
2012:
2009:
2005:
2001:
1997:
1995:
1991:
1987:
1983:
1979:
1971:
1967:
1964:
1961:
1957:
1954:
1951:
1948:
1945:
1938:
1935:
1932:
1928:
1925:
1922:
1918:
1915:
1912:
1908:
1905:
1899:
1896:
1893:
1886:
1883:
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1868:
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1866:
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1843:
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1813:
1807:
1803:
1799:
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1779:
1769:
1759:
1752:
1747:
1744:
1737:
1736:
1735:
1732:
1725:
1723:
1710:
1703:clutter power
1697:
1683:
1670:
1663:dynamic range
1657:
1643:
1630:
1606:
1597:
1565:carrier power
1555:
1547:
1544:dynamic range
1530:
1528:
1526:
1522:
1518:
1514:
1509:
1506:
1498:
1496:
1487:
1481:
1478:
1471:
1465:
1464:
1463:
1449:
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1435:
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1302:
1298:
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1255:
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1235:
1227:
1225:
1219:
1217:
1204:
1193:
1185:
1182:
1172:
1169:
1163:
1146:
1144:
1141:
1128:
1111:
1102:
1097:
1080:
1078:
1076:
1071:
1069:
1064:
1062:
1057:
1055:
1054:dynamic range
1051:
1044:
1036:
1034:
1032:
1027:
1023:
1021:
1017:
1012:
1008:
1006:
1002:
998:
994:
989:
982:
975:
973:
971:
967:
963:
959:
955:
951:
947:
942:
940:
935:
933:
929:
925:
921:
917:
915:
911:
904:
900:
897:
893:
890:
889:
888:
885:
883:
878:
875:
870:
836:
828:
824:
817:
814:
811:
803:
792:
789:
784:
781:
769:
759:
746:
738:
734:
723:
720:
715:
712:
701:
692:
691:weather radar
686:
685:is not used.
679:
677:
640:
634:
628:
625:
614:
608:
600:
597:
589:
584:
571:
566:
562:
556:
553:
550:
544:
514:
504:
489:
482:
465:
461:
453:
452:
451:
437:
425:
420:
409:
406:
401:
397:
393:
389:
384:
377:
371:
368:
363:
359:
352:
349:
343:
339:
336:
331:
327:
323:
320:
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308:
306:
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298:
294:
281:
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267:
259:
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250:
237:
228:
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208:
201:
195:
188:
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184:
179:
177:
173:
169:
165:
160:
158:
153:
151:
147:
143:
139:
134:
132:
131:weather radar
128:
123:
121:
117:
108:
106:
104:
100:
96:
92:
88:
84:
79:
77:
72:
68:
64:
63:CIM-10 Bomarc
59:
57:
53:
49:
45:
41:
32:
19:
18:Pulse-Doppler
2656:
2648:Bibliography
2634:the original
2621:
2609:. Retrieved
2597:
2585:. Retrieved
2572:
2561:. Retrieved
2557:the original
2543:
2529:
2515:
2497:
2486:. Retrieved
2477:
2465:. Retrieved
2461:the original
2451:
2440:. Retrieved
2436:the original
2426:
2415:. Retrieved
2408:the original
2395:
2384:. Retrieved
2380:the original
2370:
2361:
2326:
2316:
2298:
2289:
2251:
2175:
2172:
2164:
2161:
2153:
2150:
2134:
2123:
2107:
2097:
2082:
2075:
2063:
2061:
2052:
2046:
2035:
2024:
2016:
2013:
2002:
1998:
1985:
1975:
1970:noise figure
1965:
1955:
1949:
1936:
1926:
1916:
1906:
1897:
1884:
1875:
1869:
1864:
1733:
1729:
1694:target power
1684:
1644:
1534:
1510:
1502:
1494:
1393:
1389:
1379:phased-array
1376:
1372:
1369:
1349:
1341:
1338:
1332:
1322:
1319:
1316:
1287:
1276:
1267:conical scan
1260:
1256:
1253:
1244:
1237:
1223:
1150:
1142:
1084:
1072:
1065:
1058:
1046:
1028:
1024:
1013:
1009:
990:
987:
943:
936:
927:
918:
908:
886:
879:
873:
871:
808:ground speed
760:
687:
683:
605:target speed
585:
530:
312:
309:
304:
295:
233:
213:
180:
161:
154:
135:
124:
112:
80:
60:
39:
37:
2587:January 29,
2467:January 29,
2214:Fm-cw radar
2120:Helicopters
2114:time domain
1726:Performance
1611:filter size
1603:sample bits
1587:filter size
1568:noise power
1505:diffraction
1499:Diffraction
1342:First, the
1283:Phase noise
1050:phase noise
305:phase shift
116:phase-shift
56:electronics
2679:Categories
2563:2011-09-06
2488:2024-03-15
2442:2011-09-04
2417:2011-09-04
2386:2011-09-04
2281:References
2158:Multi-mode
2130:helicopter
2112:back into
1517:Refraction
1307:Scalloping
1016:dwell time
976:Detriments
958:helicopter
87:wind speed
2611:August 2,
1980:with the
1804:π
1789:σ
1439:×
1433:×
1329:Windowing
1273:Coherency
1263:monopulse
1194:×
1186:×
1173:×
1112:×
1077:process.
1070:process.
952:. Medium
857:Θ
821:Θ
818:
812:×
804:−
793:×
782:×
724:×
713:×
664:Θ
661:Δ
632:Δ
629:π
621:Θ
618:Δ
615:λ
567:λ
560:Δ
554:π
542:Θ
539:Δ
512:Δ
490:λ
432:Θ
429:Δ
417:Θ
410:
385:λ
375:Δ
353:π
340:
268:×
260:×
189:Principle
157:AN/SPG-51
2353:14786782
2308:Raytheon
2220:Aliasing
2184:See also
2142: Hz
2091:and not
2089:air mass
2042:resolved
2038:detected
1297:klystron
1258:future.
680:Benefits
150:coherent
142:klystron
93:used in
1366:Antenna
1001:Kitchen
997:Harpoon
109:History
2663:
2351:
2341:
2272:
2261:
1865:where
1513:L-band
1462:where
1358:. The
1003:, and
993:Exocet
849:where
653:where
450:where
144:, the
67:ramjet
2685:Radar
2637:(PDF)
2630:(PDF)
2606:(PDF)
2411:(PDF)
2404:(PDF)
2349:S2CID
2138:20โ20
2032:Track
301:phase
44:radar
42:is a
2661:ISBN
2613:2011
2589:2011
2469:2011
2339:ISBN
2270:ISBN
2259:ISBN
2062:The
2053:Lock
2040:and
2029:Scan
1992:and
1892:gain
1698:>
1519:for
1291:and
1265:and
922:and
829:>
739:>
162:The
2331:doi
2140:000
1584:PRF
1551:min
1489:PRF
1473:SCV
1443:PRF
1424:SCV
1177:PRF
1108:PRF
1020:MTI
962:jet
815:cos
531:So
407:sin
337:sin
2681::
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2306:.
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1890:=
1800:16
1477:dB
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1966:N
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1956:B
1950:T
1946:,
1940:B
1937:k
1927:D
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1907:ฯ
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