216:
970:
1630:
20:
183:
873:. 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.
1527:
836:
1204:
673:
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
1362:
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.
865:
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
677:
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
62:
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
1370:
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
1246:
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
2124:
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
1014:
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
746:
1625:{\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}}.}
1234:
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.
1335:
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.
1719:
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.
753:
1849:
1128:
281:
437:
999:
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.
94:, 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.
1496:
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.
1670:
1999:
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.
915:(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
1710:
1143:
2154:
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
1375:
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.
685:
640:
1449:
63:
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 "
1036:
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
1988:
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.
1077:
571:
230:
1309:
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
305:
102:
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
1379:
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.
1729:
1637:
1524:
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.
2162:
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.
1003:
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
831:{\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}},}
203:
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
1677:
905:
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.
2140:
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.
2003:
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.
1132:
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.
2105:
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.
1343:
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
2282:
Tactical missile aerodynamics, Volume 141. P17. Michael J. Hemsch, American
Institute of Aeronautics and Astronautics. American Institute of Aeronautics and Astronautics, 1992
582:
196:
663:
1306:
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.
1390:
1243:
Radar systems require angular measurement. Transponders are not normally associated with pulse-Doppler radar, so sidelobe suppression is required for practical operation.
1140:
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:
514:
489:
67:" capability. A secondary advantage in military radar is to reduce the transmitted power while achieving acceptable performance for improved safety of stealthy radar.
856:
980:
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
467:
1284:
are not appropriate because noise introduced by these devices interfere with detection performance. The only amplification devices suitable for pulse-Doppler are
58:
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
1199:{\displaystyle {\text{velocity resolution}}={\frac {C\times {\text{PRF}}}{2\times {\text{transmit frequency}}\times {\text{filter size in transmit pulses}}}}.}
2137:
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.
1074:
The range resolution is the minimal range separation between two objects traveling at the same speed before the radar can detect two discrete reflections:
2090:
selectively excludes low-velocity reflections so that no detections occurs below a threshold velocity. This eliminates terrain, weather, biologicals, and
2703:
741:{\displaystyle \left\vert {\frac {{\text{Doppler frequency}}\times C}{2\times {\text{transmit frequency}}}}\right\vert >{\text{velocity threshold}}.}
523:
996:. 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.
2227:
1492:
Choppy surfaces, like waves and trees, form a diffraction grating suitable for bending microwave signals. Pulse-Doppler can be so sensitive that
2615:
1018:
The antenna type is an important consideration for multi-mode radar because undesirable phase shift introduced by the radar antenna can degrade
884:
870:
575:
This allows the radar to separate the reflections from multiple objects located in the same volume of space by separating the objects using a
1674:
A small fast-moving target reflection can be detected in the presence of larger slow-moving clutter reflections when the following is true:
2143:
Similar techniques are required to develop track information for jamming signals and interference that cannot satisfy the lock criterion.
170:
It became possible to use pulse-Doppler radar on aircraft after digital computers were incorporated in the design. Pulse-Doppler provided
2389:
2445:
1512:
uses variable density in the air column above the surface of the earth to bend RF signals. An inversion layer can produce a transient
141:, but more sophisticated techniques were developed that record the phase of each transmitted pulse for comparison to returned echoes.
137:, and solid state devices. Early pulse-dopplers were incompatible with other high power microwave amplification devices that are not
2537:
2364:
1844:{\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}},}
880:
Allows the radar antenna to be pointed directly at the ground without overwhelming the computer and without reducing sensitivity.
148:
B developed during the 1950s specifically for the purpose of operating in hurricane conditions with no performance degradation.
2044:
indicates the difference between the two measurements is below a threshold, which can only occur with an object that satisfies
1123:{\displaystyle {\text{range resolution}}={\frac {C}{{\text{PRF}}\times ({\text{number of samples between transmit pulses}})}}.}
288:
is essential for pulse-Doppler radar operation. As the reflector moves between each transmit pulse, the returned signal has a
2541:
2331:
2091:
2066:
2420:
1351:
is the most effective because it produces a flat processing floor with no ringing that would otherwise cause false alarms.
276:{\displaystyle {\text{Doppler frequency}}={\frac {2\times {\text{transmit frequency}}\times {\text{radial velocity}}}{C}}.}
152:
432:{\displaystyle I=I_{0}\sin \left({\frac {4\pi (x_{0}+v\Delta t)}{\lambda }}\right)=I_{0}\sin(\Theta _{0}+\Delta \Theta ),}
2509:
2156:
973:
Maximum range from reflectivity (red) and unambiguous
Doppler velocity range (blue) with a fixed pulse repetition rate.
750:
In airborne pulse-Doppler radar, the velocity threshold is offset by the speed of the aircraft relative to the ground.
207:, so the distance to the object is the elapsed time multiplied by the speed of light, divided by two – there and back.
2059:
2653:
2495:
2262:
2251:
2025:
Scan mode involves frequency filtering, amplitude thresholding, and ambiguity resolution. Once a reflection has been
1228:
2033:, the pulse-Doppler radar automatically transitions to tracking mode for the volume of space surrounding the track.
977:
Ambiguity processing is required when target range is above the red line in the graphic, which increases scan time.
2678:
2113:
Special consideration is required for aircraft with large moving parts because pulse-Doppler radar operates like a
1634:
Subclutter visibility is the ratio of the smallest signal that can be detected in the presence of a larger signal.
2693:
2087:
1996:
1992:
1978:
1031:
945:(PRF) reflected microwave signals fall between 1,500 and 15,000 cycle per second, which is audible. This means a
118:
and moving target indicator radar, which can mask aircraft reflections. This phenomenon was adapted for use with
1348:
2683:
2214:
1665:{\displaystyle {\text{subclutter visibility}}={\frac {\text{dynamic range}}{\text{CFAR detection threshold}}}.}
1063:
39:
of the returned signal to determine the target object's velocity. It combines the features of pulse radars and
2688:
1995:
integrates all of the energy from all of the individual reflected pulses that enter the filter. This means a
1948:
1267:
2708:
2698:
2178:
934:
156:
1231:(PRF) from about 3 kHz to 30 kHz. The range between transmit pulses is 5 km to 50 km.
1513:
296:, from pulse to pulse. This causes the reflector to produce Doppler modulation on the reflected signal.
2316:
Proceedings of the 5th International ICST Conference on Pervasive Computing Technologies for Healthcare
1222:
1213:
Pulse-Doppler radar has special requirements that must be satisfied to achieve acceptable performance.
1056:
942:
126:
1705:{\displaystyle {\text{target power}}>{\frac {\text{clutter power}}{\text{subclutter visibility}}}.}
1332:
107:
on the transmit pulse that can produce signal cancellation. Doppler has maximum detrimental effect on
2622:
2310:
Liang, Liu; Popescu, Mihail; Skubic, Marjorie; Rantz, Marilyn; Yardibi, Tarik; Cuddihy, Paul (2011).
2231:
2026:
1547:
645:
174:
capability to support air-to-air missile systems in most modern military aircraft by the mid 1970s.
2591:
2566:
2395:. National Oceanic and Atmospheric Administration, National Severe Storm Laboratory. Archived from
2166:
1008:
891:
79:
2159:
to automatically adjust Doppler rejection speed within the volume of space surrounding the track.
2048:. Other types of electronic signals cannot produce a lock. Lock exists in no other type of radar.
1359:
Pulse-Doppler radar is generally limited to mechanically aimed antennas and active phased arrays.
2236:
1484:
The antenna type and scan performance is a practical consideration for multi-mode radar systems.
1281:
1019:
912:
108:
2117:. Blade tips moving near the speed of sound produce the only signal that can be detected when a
1919:
1509:
1372:
1344:
1274:
reduces sub-clutter visibility performance by producing apparent motion on stationary objects.
938:
2491:
496:
474:
2323:
2196:
841:
40:
2396:
227:, where movement in range produces frequency shift on the signal reflected from the target.
125:
Pulse-Doppler radar was developed during World War II to overcome limitations by increasing
78:
from the velocity of any precipitation in the air. Pulse-Doppler radar is also the basis of
2449:
2151:
Pulse-Doppler radar must be multi-mode to handle aircraft turning and crossing trajectory.
2030:
1973:
and accounting for in-band noise distribution across multiple detection filters. The value
1049:
902:
445:
171:
164:
64:
961:
produce a tone. The actual size of the target can be calculated using the audible signal.
8:
2570:
2545:
2081:
2045:
2006:
These improvements are the reason pulse-Doppler is essential for military and astronomy.
1982:
1970:
1899:
1289:
138:
134:
104:
91:
35:
system that determines the range to a target using pulse-timing techniques, and uses the
2368:
2292:
1371:
places Doppler modulation onto stationary clutter. That receive modulation corrupts the
1325:
pose a problem with search, detection, and ambiguity resolution in pulse-Doppler radar.
635:{\displaystyle v={\text{target speed}}={\frac {\lambda \Delta \Theta }{4\pi \Delta t}},}
2337:
1932:
1880:
1384:
1004:
993:
954:
2065:
Lock eliminates the need for human intervention with the exception of helicopters and
1055:
The received signals from multiple PRF are compared to determine true range using the
111:
systems, which must use reverse phase shift for Doppler compensation in the detector.
2649:
2327:
2258:
2247:
2114:
2073:
2037:
1444:{\displaystyle T={\frac {1}{e^{\frac {\text{SCV}}{20}}\times S\times {\text{PRF}}}},}
1322:
985:
958:
908:
858:
is the angle offset between the antenna position and the aircraft flight trajectory.
2341:
2133:), which is used for target classification in addition to the kinds of conventional
2390:"Path to Nexrad, Doppler Radar Development at the National Severe Storm Laboratory"
2319:
2098:
1301:
1277:
1255:
927:
920:
59:
2523:
2040:, where Doppler velocity is compared with the range movement on successive scans.
1966:
302:
The amplitude of the successively returning pulse from the same scanned volume is
1340:
1251:
933:
Audible Doppler and target size support passive vehicle type classification when
898:
576:
285:
83:
2424:
2673:
2311:
224:
204:
160:
87:
36:
1041:
during the detection interval, and the receiver must have large instantaneous
215:
2667:
2190:
2184:
2134:
1042:
679:
289:
119:
71:
51:
1958:
1909:
1367:
950:
926:
Pulse-Doppler provides an advantage when attempting to detect missiles and
2217:- velocity measurements in medical ultrasound. Based on the same principle
1504:
or lower to extend the horizon, which is very different from diffraction.
2367:. IEEE New Hampshire Section, University of New Hampshire. Archived from
2202:
2102:
1493:
1271:
1038:
44:
969:
159:
interceptor aircraft for the United States Air Force, and later for the
2165:
Multi-mode operation may also include continuous wave illumination for
2118:
1505:
1314:
with a pattern of discrete ranges, each of which has a blind velocity.
946:
75:
1383:
The following gives the maximum permissible settling time for antenna
923:). This flying technique is ineffective against pulse-Doppler radar.
299:
Pulse-Doppler radars exploit this phenomenon to improve performance.
145:
2646:
X-Fighters: USAF Experimental and Prototype Fighters, XP-59 to YF-23
2296:
2208:
2077:
1285:
130:
114:
Doppler weather effects (precipitation) were also found to degrade
2312:"Automatic fall detection based on Doppler radar motion signature"
1977:
is added to the standard radar range equation to account for both
1007:. Antenna motion for pulse-Doppler must be as slow as radar using
566:{\displaystyle \Delta \Theta ={\frac {4\pi v\Delta t}{\lambda }}.}
155:
was a prototype airborne radar/combination system for the planned
122:
in the 1950s after declassification of some World War II systems.
19:
1465:
2257:
Advanced Radar Techniques and Systems edited by Gaspare Galati (
2084:, so the lock criterion is not normally used for weather radar.
1516:
that traps RF signals in a thin layer of air like a wave-guide.
866:
in radar intended to detect and report aircraft and spacecraft.
2097:
The target Doppler signal from the detection is converted from
1501:
981:
182:
55:
2365:"Clutter Rejection (Pulse Doppler), Radar Systems Engineering"
989:
115:
32:
2472:"Powerofpulse.com - North American Economic and Health Site"
2471:
1250:
The two angle error techniques used with tracking radar are
43:, which were formerly separate due to the complexity of the
2230:
presentation, which highlights the advantages of using the
2205:(non-pulsed, swept frequency, range and Doppler processing)
1615:
1339:
Second, the shape of the receive pulse is adjusted using a
890:
Increases detection range by 300% or more in comparison to
195:
2014:
Pulse-Doppler radar for aircraft detection has two modes.
1366:
Doppler is incompatible with most electronically steered
2309:
54:, an American long range supersonic missile powered by
1570:
1551:
1474:= number of range samples between each transmit pulse,
1892:= effective aperture (area) of the receiving antenna,
1732:
1680:
1640:
1530:
1393:
1146:
1080:
844:
756:
688:
648:
585:
526:
499:
477:
448:
308:
233:
163:. The US's first pulse-Doppler radar, the system had
70:
Pulse-Doppler techniques also find widespread use in
50:
The first operational pulse-Doppler radar was in the
2241:
Introduction to Principles and Applications of Radar
887:
for small object detection near terrain and weather.
219:
Change of wavelength caused by motion of the source
2492:"AN/SPS-49 Very Long-Range Air Surveillance Radar"
1843:
1704:
1664:
1624:
1443:
1198:
1122:
883:Fills in the vulnerability region associated with
850:
830:
740:
657:
634:
565:
508:
483:
461:
431:
275:
2648:. St. Paul, Minnesota: Motorbooks International.
1723:The theoretical range performance is as follows.
1500:Refraction and ducting use transmit frequency at
1062:The received signals are also compared using the
167:capability and could track one target at a time.
2665:
1539:
861:Surface reflections appear in almost all radar.
144:Early examples of military systems includes the
2055:needs to be satisfied during normal operation.
1918:= Doppler filter size (transmit pulses in each
930:flying near terrain, sea surface, and weather.
2584:
2446:"Subclutter Visibility and Improvement Factor"
2423:. Weather Beacon Doppler Radar. Archived from
1048:Pulse-Doppler signal processing also includes
876:Pulse-Doppler radar corrects this as follows.
2211:- the reason for ambiguous velocity estimates
1216:
1480:= maximal design pulse repetition frequency.
665:is the phase shift induced by range motion.
2643:
2060:Pulse-Doppler signal processing § Lock
1902:, or scattering coefficient, of the target,
2704:Science and technology during World War II
1965:This equation is derived by combining the
894:(MTI) by improving sub-clutter visibility.
869:Clutter creates a vulnerability region in
2187:(non-pulsed; used for navigation systems)
2121:is moving slow near terrain and weather.
2009:
1108:number of samples between transmit pulses
2324:10.4108/icst.pervasivehealth.2011.245993
1566:transmit noise, where bandwidth is
1519:
1208:
968:
214:
194:
181:
18:
2246:Modern Radar Systems by Hamish Meikle (
210:
129:. This required the development of the
2666:
2592:"High Power L Band Fast Phase Shifter"
2094:with the exception of decoy aircraft.
1238:
1135:
2559:
2542:Massachusetts Institute of Technology
2199:(non-pulsed, pure Doppler processing)
1949:receiver bandwidth (band-pass filter)
1052:to identify true range and velocity.
1025:
223:Pulse-Doppler radar is based on the
190:
153:Hughes AN/ASG-18 Fire Control System
23:Airborne pulse-Doppler radar antenna
1069:
13:
2621:. Norhrop Grummond. Archived from
2438:
2181:(fundamentals of the radar signal)
1910:antenna pattern propagation factor
901:of about 60 dB is needed for
845:
809:
652:
649:
620:
609:
606:
548:
530:
527:
500:
420:
417:
405:
363:
74:, allowing the radar to determine
14:
2720:
2496:Federation of American Scientists
2293:"AN/APQ-174/186 Multi-Mode Radar"
2221:
1229:medium pulse repetition frequency
885:pulse-amplitude time-domain radar
871:pulse-amplitude time-domain radar
2193:(pulsed with Doppler processing)
1328:Ringing is reduced in two ways.
579:to segregate different signals:
469:is the distance radar to target,
186:Principle of pulse-Doppler radar
2636:
2608:
2530:
2516:
2502:
2484:
2088:Pulse-Doppler signal processing
1997:pulse-Doppler signal processing
1993:Pulse-Doppler signal processing
1979:pulse-Doppler signal processing
1266:Pulse-Doppler radar requires a
1032:Pulse-Doppler signal processing
516:is the time between two pulses.
2510:"Dwell Time and Hits Per Scan"
2464:
2421:"How does Doppler Radar Work?"
2413:
2382:
2357:
2348:
2303:
2285:
2276:
2108:
1983:transmitter FM noise reduction
1714:
1487:
1458:= phase shifter settling time,
1187:filter size in transmit pulses
1111:
1103:
1064:frequency ambiguity resolution
658:{\displaystyle \Delta \Theta }
423:
401:
369:
344:
1:
2269:
2146:
1295:
1227:Pulse-Doppler typically uses
964:
959:Aircraft with no moving parts
2243:course at University of Iowa
2179:Radar signal characteristics
1883:of the transmitting antenna,
1464:= sub-clutter visibility in
1317:
1261:
1022:for sub-clutter visibility.
949:sounds like a helicopter, a
935:identification friend or foe
899:Clutter rejection capability
177:
157:North American XF-108 Rapier
7:
2172:
1333:shape of the transmit pulse
1292:, and solid state devices.
1015:horizon with clear skies).
668:
10:
2725:
2616:"AWACS Surveillance Radar"
1354:
1299:
1223:Pulse repetition frequency
1220:
1217:Pulse repetition frequency
1057:range ambiguity resolution
1029:
943:pulse repetition frequency
928:low observability aircraft
127:pulse repetition frequency
97:
2232:autocorrelation technique
1861:= distance to the target,
199:Principle of pulsed radar
2567:"Dolph-Chebyshev Window"
2318:. IEEE PervasiveHealth.
2167:semi-active radar homing
2072:Weather phenomenon obey
2036:Track mode works like a
1655:CFAR detection threshold
1270:with very little noise.
1020:performance measurements
937:is not available from a
892:moving target indication
509:{\displaystyle \Delta t}
491:is the radar wavelength,
484:{\displaystyle \lambda }
80:synthetic aperture radar
2679:Radar signal processing
2538:"Side Lobe Suppression"
2524:"Side Lobe Suppression"
2354:Pace 1991, p. 152.
1941:= absolute temperature,
1282:crossed-field amplifier
957:sound like propellers.
953:sounds like a jet, and
913:moving target indicator
851:{\displaystyle \Theta }
109:moving target indicator
2694:Navigational equipment
2010:Aircraft tracking uses
1920:Fast Fourier transform
1845:
1706:
1666:
1626:
1609:receiver dynamic range
1510:over-the-horizon radar
1445:
1373:measure of performance
1349:Dolph-Chebyshev window
1345:fast Fourier transform
1200:
1124:
974:
917:flying below the radar
852:
832:
742:
659:
636:
567:
510:
485:
463:
433:
277:
220:
200:
187:
41:continuous-wave radars
24:
2684:Measuring instruments
2197:Continuous-wave radar
1846:
1707:
1695:subclutter visibility
1667:
1643:subclutter visibility
1627:
1520:Subclutter visibility
1446:
1209:Special consideration
1201:
1125:
972:
853:
833:
743:
660:
637:
568:
511:
486:
464:
462:{\displaystyle x_{0}}
434:
278:
218:
198:
185:
72:meteorological radars
22:
2689:Microwave technology
2644:Pace, Steve (1991).
2157:radar track function
1870:= transmitter power,
1730:
1678:
1638:
1528:
1391:
1144:
1078:
1050:ambiguity resolution
919:to avoid detection (
903:look-down/shoot-down
842:
754:
686:
646:
583:
524:
497:
475:
446:
306:
231:
211:Velocity measurement
172:look-down/shoot-down
165:look-down/shoot-down
65:look-down/shoot-down
16:Type of radar system
2709:Targeting (warfare)
2699:Air traffic control
2571:Stanford University
2526:. Radartutorial.eu.
2237:Pulse-Doppler radar
2082:Newtonian mechanics
2046:Newtonian mechanics
1900:radar cross section
1385:phase shift modules
1290:traveling wave tube
1268:coherent oscillator
1239:Angular measurement
1149:velocity resolution
1136:Velocity resolution
994:air-to-air missiles
732:velocity threshold
135:traveling wave tube
92:air traffic control
29:pulse-Doppler radar
2452:on January 1, 2011
2215:Doppler sonography
2092:mechanical jamming
2067:electronic jamming
1933:Boltzmann constant
1841:
1702:
1662:
1622:
1614:
1579:
1560:
1441:
1196:
1179:transmit frequency
1120:
975:
955:propeller aircraft
939:transponder signal
848:
828:
822:velocity threshold
786:transmit frequency
738:
717:transmit frequency
678:is much lower for
655:
632:
563:
506:
481:
459:
429:
273:
253:transmit frequency
221:
201:
188:
116:conventional radar
25:
2333:978-1-936968-15-2
2115:phase-locked loop
2074:adiabatic process
2038:phase-locked loop
1835:
1821:
1808:
1774:
1764:
1754:
1697:
1696:
1693:
1684:
1657:
1656:
1653:
1644:
1610:
1601:
1593:
1578:
1577:
1574:
1567:
1559:
1558:
1555:
1534:
1436:
1433:
1418:
1414:
1323:Ringing artifacts
1191:
1188:
1180:
1167:
1150:
1115:
1109:
1098:
1084:
1026:Signal processing
909:Pulse compression
823:
798:
790:
787:
768:
767:Doppler frequency
733:
721:
718:
699:
698:Doppler frequency
627:
595:
558:
376:
268:
262:
254:
237:
236:Doppler frequency
191:Range measurement
2716:
2659:
2630:
2629:
2627:
2620:
2612:
2606:
2605:
2603:
2601:
2596:
2588:
2582:
2581:
2579:
2577:
2563:
2557:
2556:
2554:
2553:
2544:. Archived from
2534:
2528:
2527:
2520:
2514:
2513:
2512:. Radartutorial.
2506:
2500:
2499:
2488:
2482:
2481:
2479:
2478:
2468:
2462:
2461:
2459:
2457:
2448:. Archived from
2442:
2436:
2435:
2433:
2432:
2417:
2411:
2410:
2408:
2407:
2401:
2394:
2386:
2380:
2379:
2377:
2376:
2361:
2355:
2352:
2346:
2345:
2307:
2301:
2300:
2289:
2283:
2280:
2132:
2130:
2099:frequency domain
2076:associated with
1850:
1848:
1847:
1842:
1837:
1836:
1828:
1826:
1822:
1820:
1810:
1809:
1806:
1800:
1799:
1786:
1776:
1775:
1772:
1766:
1765:
1762:
1756:
1755:
1752:
1745:
1711:
1709:
1708:
1703:
1698:
1694:
1691:
1690:
1685:
1682:
1671:
1669:
1668:
1663:
1658:
1654:
1651:
1650:
1645:
1642:
1631:
1629:
1628:
1623:
1618:
1617:
1611:
1608:
1604:
1603:
1602:
1599:
1594:
1591:
1580:
1575:
1572:
1571:
1568:
1565:
1561:
1556:
1553:
1552:
1535:
1532:
1514:troposphere duct
1479:
1473:
1463:
1457:
1450:
1448:
1447:
1442:
1437:
1435:
1434:
1431:
1420:
1419:
1412:
1411:
1401:
1302:Radar scalloping
1278:Cavity magnetron
1205:
1203:
1202:
1197:
1192:
1190:
1189:
1186:
1181:
1178:
1169:
1168:
1165:
1156:
1151:
1148:
1129:
1127:
1126:
1121:
1116:
1114:
1110:
1107:
1099:
1096:
1090:
1085:
1083:range resolution
1082:
1070:Range resolution
921:nap-of-the-earth
857:
855:
854:
849:
837:
835:
834:
829:
824:
821:
816:
812:
799:
796:
791:
789:
788:
785:
776:
769:
766:
763:
747:
745:
744:
739:
734:
731:
726:
722:
720:
719:
716:
707:
700:
697:
694:
664:
662:
661:
656:
641:
639:
638:
633:
628:
626:
612:
601:
596:
593:
572:
570:
569:
564:
559:
554:
537:
515:
513:
512:
507:
490:
488:
487:
482:
468:
466:
465:
460:
458:
457:
438:
436:
435:
430:
413:
412:
394:
393:
381:
377:
372:
356:
355:
336:
324:
323:
282:
280:
279:
274:
269:
264:
263:
260:
255:
252:
243:
238:
235:
90:and mapping. In
60:fighter aircraft
2724:
2723:
2719:
2718:
2717:
2715:
2714:
2713:
2664:
2663:
2662:
2656:
2639:
2634:
2633:
2625:
2618:
2614:
2613:
2609:
2599:
2597:
2594:
2590:
2589:
2585:
2575:
2573:
2565:
2564:
2560:
2551:
2549:
2536:
2535:
2531:
2522:
2521:
2517:
2508:
2507:
2503:
2490:
2489:
2485:
2476:
2474:
2470:
2469:
2465:
2455:
2453:
2444:
2443:
2439:
2430:
2428:
2419:
2418:
2414:
2405:
2403:
2399:
2392:
2388:
2387:
2383:
2374:
2372:
2363:
2362:
2358:
2353:
2349:
2334:
2308:
2304:
2291:
2290:
2286:
2281:
2277:
2272:
2224:
2175:
2149:
2128:
2126:
2111:
2012:
1930:
1891:
1878:
1869:
1827:
1805:
1801:
1795:
1791:
1787:
1771:
1767:
1761:
1757:
1751:
1747:
1746:
1744:
1740:
1739:
1731:
1728:
1727:
1717:
1689:
1681:
1679:
1676:
1675:
1649:
1641:
1639:
1636:
1635:
1613:
1612:
1607:
1605:
1598:
1590:
1589:
1585:
1582:
1581:
1569:
1564:
1562:
1550:
1543:
1542:
1531:
1529:
1526:
1525:
1522:
1490:
1477:
1471:
1461:
1455:
1430:
1410:
1406:
1405:
1400:
1392:
1389:
1388:
1357:
1341:window function
1320:
1304:
1298:
1264:
1241:
1225:
1219:
1211:
1185:
1177:
1170:
1164:
1157:
1155:
1147:
1145:
1142:
1141:
1138:
1106:
1095:
1094:
1089:
1081:
1079:
1076:
1075:
1072:
1034:
1028:
967:
843:
840:
839:
820:
795:
784:
777:
765:
764:
762:
761:
757:
755:
752:
751:
730:
715:
708:
696:
695:
693:
689:
687:
684:
683:
671:
647:
644:
643:
613:
602:
600:
592:
584:
581:
580:
577:spread spectrum
538:
536:
525:
522:
521:
498:
495:
494:
476:
473:
472:
453:
449:
447:
444:
443:
408:
404:
389:
385:
351:
347:
337:
335:
331:
319:
315:
307:
304:
303:
292:difference, or
286:Radial velocity
261:radial velocity
259:
251:
244:
242:
234:
232:
229:
228:
213:
193:
180:
100:
84:radar astronomy
17:
12:
11:
5:
2722:
2712:
2711:
2706:
2701:
2696:
2691:
2686:
2681:
2676:
2661:
2660:
2654:
2640:
2638:
2635:
2632:
2631:
2628:on 2009-02-27.
2607:
2583:
2558:
2529:
2515:
2501:
2483:
2463:
2437:
2412:
2381:
2356:
2347:
2332:
2302:
2284:
2274:
2273:
2271:
2268:
2267:
2266:
2255:
2244:
2239:handouts from
2234:
2223:
2222:External links
2220:
2219:
2218:
2212:
2206:
2200:
2194:
2188:
2182:
2174:
2171:
2148:
2145:
2125:human beings (
2110:
2107:
2063:
2062:
2053:lock criterion
2023:
2022:
2019:
2011:
2008:
1971:noise equation
1967:radar equation
1963:
1962:
1952:
1942:
1936:
1928:
1923:
1913:
1903:
1893:
1889:
1884:
1876:
1871:
1867:
1862:
1852:
1851:
1840:
1834:
1831:
1825:
1819:
1816:
1813:
1804:
1798:
1794:
1790:
1785:
1782:
1779:
1770:
1760:
1750:
1743:
1738:
1735:
1716:
1713:
1701:
1688:
1661:
1648:
1621:
1616:
1606:
1597:
1588:
1584:
1583:
1563:
1549:
1548:
1546:
1541:
1538:
1521:
1518:
1489:
1486:
1482:
1481:
1475:
1469:
1459:
1440:
1429:
1426:
1423:
1417:
1409:
1404:
1399:
1396:
1356:
1353:
1319:
1316:
1312:detection gaps
1300:Main article:
1297:
1294:
1263:
1260:
1240:
1237:
1221:Main article:
1218:
1215:
1210:
1207:
1195:
1184:
1176:
1173:
1163:
1160:
1154:
1137:
1134:
1119:
1113:
1105:
1102:
1093:
1088:
1071:
1068:
1030:Main article:
1027:
1024:
966:
963:
896:
895:
888:
881:
863:Ground clutter
847:
827:
819:
815:
811:
808:
805:
802:
794:
783:
780:
775:
772:
760:
737:
729:
725:
714:
711:
706:
703:
692:
670:
667:
654:
651:
631:
625:
622:
619:
616:
611:
608:
605:
599:
591:
588:
562:
557:
553:
550:
547:
544:
541:
535:
532:
529:
518:
517:
505:
502:
492:
480:
470:
456:
452:
428:
425:
422:
419:
416:
411:
407:
403:
400:
397:
392:
388:
384:
380:
375:
371:
368:
365:
362:
359:
354:
350:
346:
343:
340:
334:
330:
327:
322:
318:
314:
311:
272:
267:
258:
250:
247:
241:
225:Doppler effect
212:
209:
205:speed of light
192:
189:
179:
176:
161:Lockheed YF-12
99:
96:
88:remote sensing
37:Doppler effect
15:
9:
6:
4:
3:
2:
2721:
2710:
2707:
2705:
2702:
2700:
2697:
2695:
2692:
2690:
2687:
2685:
2682:
2680:
2677:
2675:
2672:
2671:
2669:
2657:
2655:0-87938-540-5
2651:
2647:
2642:
2641:
2624:
2617:
2611:
2593:
2587:
2572:
2568:
2562:
2548:on 2012-03-31
2547:
2543:
2539:
2533:
2525:
2519:
2511:
2505:
2497:
2493:
2487:
2473:
2467:
2451:
2447:
2441:
2427:on 2012-03-31
2426:
2422:
2416:
2402:on 2012-03-21
2398:
2391:
2385:
2371:on 2012-03-31
2370:
2366:
2360:
2351:
2343:
2339:
2335:
2329:
2325:
2321:
2317:
2313:
2306:
2298:
2294:
2288:
2279:
2275:
2264:
2263:0-86341-172-X
2260:
2256:
2253:
2252:1-58053-294-2
2249:
2245:
2242:
2238:
2235:
2233:
2229:
2228:Doppler radar
2226:
2225:
2216:
2213:
2210:
2207:
2204:
2201:
2198:
2195:
2192:
2191:Weather radar
2189:
2186:
2185:Doppler radar
2183:
2180:
2177:
2176:
2170:
2168:
2163:
2160:
2158:
2152:
2144:
2141:
2138:
2136:
2135:radar display
2122:
2120:
2116:
2106:
2104:
2100:
2095:
2093:
2089:
2085:
2083:
2079:
2075:
2070:
2068:
2061:
2058:
2057:
2056:
2054:
2049:
2047:
2043:
2039:
2034:
2032:
2028:
2020:
2017:
2016:
2015:
2007:
2004:
2001:
1998:
1994:
1990:
1986:
1984:
1980:
1976:
1972:
1968:
1960:
1956:
1953:
1950:
1946:
1943:
1940:
1937:
1934:
1927:
1924:
1921:
1917:
1914:
1911:
1907:
1904:
1901:
1897:
1894:
1888:
1885:
1882:
1875:
1872:
1866:
1863:
1860:
1857:
1856:
1855:
1838:
1832:
1829:
1823:
1817:
1814:
1811:
1802:
1796:
1792:
1788:
1783:
1780:
1777:
1768:
1758:
1748:
1741:
1736:
1733:
1726:
1725:
1724:
1721:
1712:
1699:
1692:clutter power
1686:
1672:
1659:
1652:dynamic range
1646:
1632:
1619:
1595:
1586:
1554:carrier power
1544:
1536:
1533:dynamic range
1517:
1515:
1511:
1507:
1503:
1498:
1495:
1485:
1476:
1470:
1467:
1460:
1454:
1453:
1452:
1438:
1427:
1424:
1421:
1415:
1407:
1402:
1397:
1394:
1386:
1381:
1377:
1374:
1369:
1364:
1360:
1352:
1350:
1346:
1342:
1337:
1334:
1329:
1326:
1324:
1315:
1313:
1307:
1303:
1293:
1291:
1287:
1283:
1279:
1275:
1273:
1269:
1259:
1257:
1253:
1248:
1244:
1236:
1232:
1230:
1224:
1214:
1206:
1193:
1182:
1174:
1171:
1161:
1158:
1152:
1133:
1130:
1117:
1100:
1091:
1086:
1067:
1065:
1060:
1058:
1053:
1051:
1046:
1044:
1043:dynamic range
1040:
1033:
1023:
1021:
1016:
1012:
1010:
1006:
1001:
997:
995:
991:
987:
983:
978:
971:
962:
960:
956:
952:
948:
944:
940:
936:
931:
929:
924:
922:
918:
914:
910:
906:
904:
900:
893:
889:
886:
882:
879:
878:
877:
874:
872:
867:
864:
859:
825:
817:
813:
806:
803:
800:
792:
781:
778:
773:
770:
758:
748:
735:
727:
723:
712:
709:
704:
701:
690:
681:
680:weather radar
675:
674:is not used.
666:
629:
623:
617:
614:
603:
597:
589:
586:
578:
573:
560:
555:
551:
545:
542:
539:
533:
503:
493:
478:
471:
454:
450:
442:
441:
440:
426:
414:
409:
398:
395:
390:
386:
382:
378:
373:
366:
360:
357:
352:
348:
341:
338:
332:
328:
325:
320:
316:
312:
309:
300:
297:
295:
291:
287:
283:
270:
265:
256:
248:
245:
239:
226:
217:
208:
206:
197:
184:
175:
173:
168:
166:
162:
158:
154:
149:
147:
142:
140:
136:
132:
128:
123:
121:
120:weather radar
117:
112:
110:
106:
95:
93:
89:
85:
81:
77:
73:
68:
66:
61:
57:
53:
52:CIM-10 Bomarc
48:
46:
42:
38:
34:
30:
21:
2645:
2637:Bibliography
2623:the original
2610:
2598:. Retrieved
2586:
2574:. Retrieved
2561:
2550:. Retrieved
2546:the original
2532:
2518:
2504:
2486:
2475:. Retrieved
2466:
2454:. Retrieved
2450:the original
2440:
2429:. Retrieved
2425:the original
2415:
2404:. Retrieved
2397:the original
2384:
2373:. Retrieved
2369:the original
2359:
2350:
2315:
2305:
2287:
2278:
2240:
2164:
2161:
2153:
2150:
2142:
2139:
2123:
2112:
2096:
2086:
2071:
2064:
2052:
2050:
2041:
2035:
2024:
2013:
2005:
2002:
1991:
1987:
1974:
1964:
1959:noise figure
1954:
1944:
1938:
1925:
1915:
1905:
1895:
1886:
1873:
1864:
1858:
1853:
1722:
1718:
1683:target power
1673:
1633:
1523:
1499:
1491:
1483:
1382:
1378:
1368:phased-array
1365:
1361:
1358:
1338:
1330:
1327:
1321:
1311:
1308:
1305:
1276:
1265:
1256:conical scan
1249:
1245:
1242:
1233:
1226:
1212:
1139:
1131:
1073:
1061:
1054:
1047:
1035:
1017:
1013:
1002:
998:
979:
976:
932:
925:
916:
907:
897:
875:
868:
862:
860:
797:ground speed
749:
676:
672:
594:target speed
574:
519:
301:
298:
293:
284:
222:
202:
169:
150:
143:
124:
113:
101:
69:
49:
28:
26:
2576:January 29,
2456:January 29,
2203:Fm-cw radar
2109:Helicopters
2103:time domain
1715:Performance
1600:filter size
1592:sample bits
1576:filter size
1557:noise power
1494:diffraction
1488:Diffraction
1331:First, the
1272:Phase noise
1039:phase noise
294:phase shift
105:phase-shift
45:electronics
2668:Categories
2552:2011-09-06
2477:2024-03-15
2431:2011-09-04
2406:2011-09-04
2375:2011-09-04
2270:References
2147:Multi-mode
2119:helicopter
2101:back into
1506:Refraction
1296:Scalloping
1005:dwell time
965:Detriments
947:helicopter
76:wind speed
2600:August 2,
1969:with the
1793:π
1778:σ
1428:×
1422:×
1318:Windowing
1262:Coherency
1252:monopulse
1183:×
1175:×
1162:×
1101:×
1066:process.
1059:process.
941:. Medium
846:Θ
810:Θ
807:
801:×
793:−
782:×
771:×
713:×
702:×
653:Θ
650:Δ
621:Δ
618:π
610:Θ
607:Δ
604:λ
556:λ
549:Δ
543:π
531:Θ
528:Δ
501:Δ
479:λ
421:Θ
418:Δ
406:Θ
399:
374:λ
364:Δ
342:π
329:
257:×
249:×
178:Principle
146:AN/SPG-51
2342:14786782
2297:Raytheon
2209:Aliasing
2173:See also
2131: Hz
2080:and not
2078:air mass
2031:resolved
2027:detected
1286:klystron
1247:future.
669:Benefits
139:coherent
131:klystron
82:used in
1355:Antenna
990:Kitchen
986:Harpoon
98:History
2652:
2340:
2330:
2261:
2250:
1854:where
1502:L-band
1451:where
1347:. The
992:, and
982:Exocet
838:where
642:where
439:where
133:, the
56:ramjet
2674:Radar
2626:(PDF)
2619:(PDF)
2595:(PDF)
2400:(PDF)
2393:(PDF)
2338:S2CID
2127:20–20
2021:Track
290:phase
33:radar
31:is a
2650:ISBN
2602:2011
2578:2011
2458:2011
2328:ISBN
2259:ISBN
2248:ISBN
2051:The
2042:Lock
2029:and
2018:Scan
1981:and
1881:gain
1687:>
1508:for
1280:and
1254:and
911:and
818:>
728:>
151:The
2320:doi
2129:000
1573:PRF
1540:min
1478:PRF
1462:SCV
1432:PRF
1413:SCV
1166:PRF
1097:PRF
1009:MTI
951:jet
804:cos
520:So
396:sin
326:sin
2670::
2569:.
2540:.
2494:.
2336:.
2326:.
2314:.
2295:.
2169:.
2069:.
1985:.
1957:=
1947:=
1931:=
1922:),
1908:=
1898:=
1879:=
1789:16
1466:dB
1416:20
1387:.
1288:,
1258:.
1045:.
1011:.
988:,
984:,
682:.
86:,
47:.
27:A
2658:.
2604:.
2580:.
2555:.
2498:.
2480:.
2460:.
2434:.
2409:.
2378:.
2344:.
2322::
2299:.
2265:)
2254:)
1975:D
1961:.
1955:N
1951:,
1945:B
1939:T
1935:,
1929:B
1926:k
1916:D
1912:,
1906:F
1896:σ
1890:r
1887:A
1877:t
1874:G
1868:t
1865:P
1859:R
1839:,
1833:4
1830:1
1824:)
1818:N
1815:B
1812:T
1807:B
1803:k
1797:2
1784:D
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1773:r
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1734:R
1700:.
1660:.
1647:=
1620:.
1596:+
1587:2
1545:{
1537:=
1472:S
1468:,
1456:T
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1398:=
1395:T
1194:.
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1104:(
1092:C
1087:=
826:,
814:|
779:2
774:C
759:|
736:.
724:|
710:2
705:C
691:|
630:,
624:t
615:4
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590:=
587:v
561:.
552:t
546:v
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534:=
504:t
455:0
451:x
427:,
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415:+
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402:(
391:0
387:I
383:=
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370:)
367:t
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353:0
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339:4
333:(
321:0
317:I
313:=
310:I
271:.
266:C
246:2
240:=
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