226:
2441:
775:
2686:
evaluate target size. Moving objects include birds flying near objects in front of the antenna. Reflections from small objects directly in front of the receiver can be overwhelmed by reflections entering antenna side-lobes from large object located to the side, above, or behind the radar, such as trees with wind blowing through the leaves, tall grass, sea surface, freight trains, busses, trucks, and aircraft.
2544:
measurement scene. Using directive antennas, the OTAD receiver collects both signals simultaneously and mixes the synchronisation signal with the downconverted echo signal from the measurement scene in a process known as over-the-air deramping. The frequency of deramped signal is proportional to the bistatic range to the target less the baseline distance between the OTAD transmitter and the OTAD receiver.
2697:, a truck or tree with 1,000 square feet of reflecting surface behind the antenna can produce a signal as strong as a car with 10 square feet of reflecting in front of a small hand held antenna. An area survey is required to determine if hand held devices will operate reliably because unobserved roadway traffic and trees behind the operator can interfere with observations made in front of the operator.
63:
24:
637:, and proximity sensors. Doppler shift is not always required for detection when FM is used. While early implementations, such as the APN-1 Radar Altimeter of the 1940s, were designed for short ranges, Over The Horizon Radars (OTHR) such as the Jindalee Operational Radar Network (JORN) are designed to survey intercontinental distances of some thousands of kilometres.
629:(FM-CW) ā also called continuous-wave frequency-modulated (CWFM) radar ā is a short-range measuring radar set capable of determining distance. This increases reliability by providing distance measurement along with speed measurement, which is essential when there is more than one source of reflection arriving at the radar antenna. This kind of radar is often used as "
107:. This makes it particularly useful for looking for objects against a background reflector, for instance, allowing a high-flying aircraft to look for aircraft flying at low altitudes against the background of the surface. Because the very strong reflection off the surface can be filtered out, the much smaller reflection from a target can still be seen.
1453:
2285:
863:, and the amount of frequency shift between the transmit signal and the reflected signal increases with time delay (distance). The time delay is thus a measure of the range; a small frequency spread is produced by nearby reflections, a larger frequency spread corresponds with more time delay and a longer range.
2661:
Because of simplicity, CW radar are inexpensive to manufacture, relatively free from failure, cheap to maintain, and fully automated. Some are small enough to carry in a pocket. More sophisticated CW radar systems can reliably achieve accurate detections exceeding 100 km distance while providing
2490:
Interrupted continuous-wave can be used to eliminate bleed-through between the transmit and receive antenna. This kind of system typically takes one sample between each pair of transmit pulses, and the sample rate is typically 30 kHz or more. This technique is used with the least expensive kinds
2648:
This technique turns the transmitter off for a period before receiver sampling begins. Receiver interference declines by about 8.7 dB per time constant. Leakage reduction of 120 dB requires 14 recover bandwidth time constants between when the transmitter is turned off and receiver sampling
855:
Sawtooth modulation is the most used in FM-CW radars where range is desired for objects that lack rotating parts. Range information is mixed with the
Doppler velocity using this technique. Modulation can be turned off on alternate scans to identify velocity using unmodulated carrier frequency shift.
2704:
used by law enforcement officers, NASCAR events, and sports, like baseball, golf, and tennis. Interference from a second radar, automobile ignition, other moving objects, moving fan blades on the intended target, and other radio frequency sources will corrupt measurements. These systems are limited
2665:
The FMCW ramp can be compressed providing extra signal to noise gains such one does not need the extra power that pulse radar using a no FM modulation would. This combined with the fact that it is coherent means that
Fourier integration can be used rather than azimuth integration providing superior
1460:
Sinusoidal FM is used when both range and velocity are required simultaneously for complex objects with multiple moving parts like turbine fan blades, helicopter blades, or propellers. This processing reduces the effect of complex spectra modulation produced by rotating parts that introduce errors
193:
Doubling the number of receiver filters increases distance performance by about 20%. Maximum distance performance is achieved when receiver filter size is equal to the maximum FM noise riding on the transmit signal. Reducing receiver filter size below average amount of FM transmit noise will not
2635:
The filter approach relies on using a very narrow band reject filter that will eliminate low velocity signals from nearby reflectors. The band reject area spans 10 mile per hour to 100 mile per hour depending upon the anticipated environment. Typical improvement is on the order of 30 dB to
1467:
Sinusoidal FM is eliminated by the receiver for close in reflections because the transmit frequency will be the same as the frequency being reflected back into the receiver. The spectrum for more distant objects will contain more modulation. The amount of spectrum spreading caused by modulation
2685:
Unmodulated continuous wave radar cannot measure distance. Signal amplitude provides the only way to determine which object corresponds with which speed measurement when there is more than one moving object near the receiver, but amplitude information is not useful without range measurement to
644:
varies up and down in frequency over a fixed period of time by a modulating signal. Frequency difference between the receive signal and the transmit signal increases with delay, and hence with distance. This smears out, or blurs, the
Doppler signal. Echoes from a target are then mixed with the
2543:
The bistatic FM-CW receiver and transmitter pair may also take the form of an over-the-air deramping (OTAD) system. An OTAD transmitter broadcasts an FM-CW signal on two different frequency channels; one for synchronisation of the receiver with the transmitter, the other for illuminating the
2715:
and FM range modulation are required for reliable operation. There is no way to know the direction of the arriving signal without side-lobe suppression, which requires two or more antennae, each with its own individual receiver. There is no way to know distance without FM range modulation.
2644:
While interrupted carrier systems are not considered to be CW systems, performance characteristics are sufficiently similar to group interrupted CW systems with pure CW radar because the pulse rate is high enough that range measurements cannot be done without frequency modulation (FM).
2669:
Doppler processing allows signal integration between successive receiver samples. This means that the number of samples can be increased to extend the detection range without increasing transmit power. That technique can be used to produce inexpensive stealthy low-power radar.
134:
so these are much simpler to manufacture and operate. They have no minimum or maximum range, although the broadcast power level imposes a practical limit on range. Continuous-wave radar maximize total power on a target because the transmitter is broadcasting continuously.
760:
2574:
The transmit signal will leak into the receiver on practical systems. Significant leakage will come from nearby environmental reflections even if antenna components are perfect. As much as 120 dB of leakage rejection is required to achieve acceptable performance.
2626:
The actual transmit signal is rotated 180 degrees, attenuated, and fed into the receiver. The phase shift and attenuation are set using feedback obtained from the receiver to cancel most of the leakage. Typical improvement is on the order of 30 dB to 70 dB.
2599:
Interruption applies to cheap hand held mono-static radar systems (police radar and sporting goods). This is impractical for bistatic systems because of the cost and complexity associated with coordinating time with nanosecond precision in two different locations.
2547:
Most modern systems FM-CW radars use one transmitter antenna and multiple receiver antennas. Because the transmitter is on continuously at effectively the same frequency as the receiver, special care must be exercised to avoid overloading the receiver stages.
765:
The radar will report incorrect distance for reflections from distances beyond the instrumented range, such as from the moon. FMCW range measurements are only reliable to about 60% of the instrumented range, or about 300 km for 100 Hz FM.
189:
receivers used for continuous-wave
Doppler radar receivers are very different from conventional radar receivers. The receiver consists of a bank of filters, usually more than 100. The number of filters determines the maximum distance performance.
1372:
For practical reasons, receive samples are not processed for a brief period after the modulation ramp begins because incoming reflections will have modulation from the previous modulation cycle. This imposes a range limit and limits performance.
2081:
2482:
is typically required to eliminate bleed-through between the transmitter and receiver to increase sensitivity in practical systems. This is typically used with continuous-wave angle tracking (CWAT) radar receivers that are interoperable with
2368:
681:
Range demodulation is limited to 1/4 wavelength of the transmit modulation. Instrumented range for 100 Hz FM would be 500 km. That limit depends upon the type of modulation and demodulation. The following generally applies.
2709:, so the beam spread exceeds 45 degrees if the antenna is smaller than 12 inches (0.3 meter). Significant antenna side-lobes extend in all directions unless the antenna is larger than the vehicle on which the radar is mounted.
2073:
2596:, for practical reasons because side-lobes from the illumination radar will illuminate the environment in addition to the main-lobe illumination on the target. Similar constraints apply to ground-based CW radar. This adds cost.
2652:
The interruption concept is widely used, especially in long-range radar applications where the receiver sensitivity is very important. It is commonly known as "frequency modulated interrupted continuous wave", or FMICW.
357:
962:
2535:
The receiver uses two antennas – one antenna aimed at the target and one antenna aimed at the transmit antenna. The receive antenna that is aimed at the transmit antenna is used to develop the
1305:
618:) will not cause a Doppler shift. Reflected signals from stationary and slow-moving objects are masked by the transmit signal, which overwhelms reflections from slow-moving objects during normal operation.
455:
1800:
1440:
2689:
Small radar systems that lack range modulation are only reliable when used with one object in a sterile environment free from vegetation, aircraft, birds, weather phenomenon, and other nearby vehicles.
1644:
688:
609:
1193:
1589:
859:
As shown in the figure the received waveform (green) is simply a delayed replica of the transmitted waveform (red). The transmitted frequency is used to down-convert the receive signal to
2413:
1125:
548:
506:
1464:
This technique also has the advantage that the receiver never needs to stop processing incoming signals because the modulation waveform is continuous with no impulse modulation.
103:
Doppler-analysis of radar returns can allow the filtering out of slow or non-moving objects, thus offering immunity to interference from large stationary objects and slow-moving
2429:
process is used to produce the spectrum. This is repeated with several different demodulation values. Range is found by identifying the receive spectrum where width is minimum.
1060:
1016:
2958:
2280:{\displaystyle y(t)\approx \cos \left\{-4t\pi \mathrm {B} \sin(2\pi f_{m}(2t+\delta t)\sin(\pi f_{m}\delta t)+2\delta t\pi \mathrm {B} \cos(2\pi f_{m}(t+\delta t))\right\}\,}
1354:
874:, and digital processing is performed on the result. As explained in the literature, FM-CW ranging for a linear ramp waveform is given in the following set of equations:
1832:
849:
826:
2300:
100:, which causes the received signal to have a different frequency from the transmitted signal, allowing it to be detected by filtering out the transmitted frequency.
1220:
803:
1846:
237:
when objects are moving. There is no way to evaluate distance. This type of radar is typically used with competition sports, like golf, tennis, baseball,
172:
Maximum distance in a continuous-wave radar is determined by the overall bandwidth and transmitter power. This bandwidth is determined by two factors.
165:. Since the missile is moving at high velocities relative to the aircraft, there is a strong Doppler shift. Most modern air combat radars, even
1456:
Sinusoidal FM modulation identifies range by measuring the amount of spectrum spread produced by propagation delay (AM is not used with FMCW).
2418:
Receiver demodulation is used with FMCW similar to the receiver demodulation strategy used with pulse compression. This takes place before
2971:
882:
183:
Doubling transmit power increases distance performance by about 20%. Reducing the total FM transmit noise by half has the same effect.
262:
2432:
Practical systems also process receive samples for several cycles of the FM in order to reduce the influence of sampling artifacts.
233:
This kind of radar can cost less than $ 10 (2021). Return frequencies are shifted away from the transmitted frequency based on the
1658:
2294:
can be seen in this equation, and that is a close approximation to identify the amount of spread placed on the receive spectrum:
1236:
755:{\displaystyle {\text{Instrumented Range}}=F_{r}-F_{t}={\frac {\text{Speed of Light}}{(4\times {\text{Modulation Frequency}})}}}
1600:
368:
114:
Inexpensive radio-altimeters, proximity sensors and sports accessories that operate from a few dozen feet to several kilometres
2930:
856:
This allows range and velocity to be found with one radar set. Triangle wave modulation can be used to achieve the same goal.
1381:
2419:
23:
1135:
556:
2780:
1477:
615:
614:
Continuous-wave radar without frequency modulation (FM) only detects moving targets, as stationary targets (along the
2880:
2517:
systems. The transmit radar is typically located near the missile launcher. The receiver is located in the missile.
2376:
96:
energy is transmitted and then received from any reflecting objects. Individual objects can be detected using the
633:" to measure the exact height during the landing procedure of aircraft. It is also used as early-warning radar,
1840:
The detection process down converts the receive signal using the transmit signal. This eliminates the carrier.
2562:
Monopulse antennas produce angular measurements without pulses or other modulation. This technique is used in
1073:
2722:
These limitations are due to the well known limitations of basic physics that cannot be overcome by design.
2914:
2857:
2607:
limitation of practical receiver components that include band pass filters that take time to settle out.
1228:
It is then a trivial matter to calculate the physical one-way distance for an idealized typical case as:
871:
2425:
Practical systems introduce reverse FM on the receive signal using digital signal processing before the
1021:
977:
652:
A variety of modulations are possible, the transmitter frequency can slew up and down as follows :
2804:
2674:
867:
511:
121:
CW angle track (CWAT) radar operating beyond 100 km for use with surface-to-air missile systems
2593:
2563:
2510:
139:
463:
2529:
805:
can be ignored and the transmitter's power is linearly frequency modulated, then the time delay (
2540:, which allows the target receiver to operate reliably in or near the main beam of the antenna.
2506:. The transmitter is fairly expensive, while the receiver is fairly inexpensive and disposable.
2494:
FM-CW radars can be built with one antenna using either a circulator, or circular polarization.
201:
when the receiver filter size matches the RMS bandwidth of the FM noise on the transmit signal.
2514:
2484:
2426:
2363:{\displaystyle {\text{Modulation Spectrum Spread}}\approx 2(\mathrm {B} +1)f_{m}\sin(\delta t)}
1811:
2975:
831:
808:
2291:
2770:
1320:
1198:
781:
8:
2737:
2578:
Three approaches can be used to produce a practical system that will function correctly.
166:
118:
2068:{\displaystyle y(t)=\cos \left\{2\pi (t+\delta t)\right\}\;\cos \left\{2\pi t\right\}\,}
778:
Ranging with an FM-CW radar system: if the error caused by a possible
Doppler frequency
16:
Type of radar where a known stable frequency continuous wave radio energy is transmitted
2839:
1468:
riding on the receive signal is proportional to the distance to the reflecting object.
143:
2444:
Block diagram of a simple continuous-wave radar module: Many manufacturers offer such
2896:
2876:
2843:
2776:
2537:
2479:
70:
2818:
Srivastav, A.; Nguyen, P.; McConnell, M.; Loparo, K. N.; Mandal, S. (October 2020).
2831:
2473:
2454:
1361:
646:
186:
154:
45:
2719:
Speed, direction, and distance are all required to pick out an individual object.
2557:
641:
630:
241:
racing, and some smart-home appliances including light-bulbs and motion sensors.
104:
90:
2452:
There are two different antenna configurations used with continuous-wave radar:
828:) is proportional to the difference of the transmitted and the received signal (
3015:
2503:
2460:
1357:
245:
234:
3000:
870:
is used for most detection processing. The beat signals are passed through an
225:
3009:
2835:
2755:
2731:
2604:
668:
662:
161:
the target with a CW radar signal, and the missile homes in on the reflected
150:
147:
97:
2502:
The radar receive antenna is located far from the radar transmit antenna in
460:
Since the usual variation of targets' speed of a radar is much smaller than
2819:
2525:
1652:
A time delay is introduced in transit between the radar and the reflector.
131:
2472:
The radar receive antenna is located nearby the radar transmit antenna in
2445:
674:
162:
31:
2957:, A New Multistatic FMCW Radar Architecture By Over-The-Air Deramping,
634:
179:
Receiver filter size (bandwidth divided by the total number of filters)
2712:
2701:
2694:
656:
2440:
860:
2592:
Null and filter approaches must be used with bistatic radar, like
957:{\displaystyle k={\frac {\Delta {f_{radar}}}{\Delta {t_{radar}}}}}
640:
In this system the transmitted signal of a known stable frequency
2772:
Optical
Frequency-Modulated Continuous-Wave (FMCW) Interferometry
2706:
774:
2491:
of radar, such as those used for traffic monitoring and sports.
352:{\displaystyle f_{r}=f_{t}\left({\frac {1+v/c'}{1-v/c'}}\right)}
2820:"A Highly Digital Multiantenna Ground-Penetrating Radar System"
649:
which will give the distance of the target after demodulation.
238:
2817:
1452:
110:
CW radar systems are used at both ends of the range spectrum.
93:
86:
2422:. A large modulation index is needed for practical reasons.
1795:{\displaystyle y(t)=\cos \left\{2\pi (t+\delta t)\right\}\,}
1300:{\displaystyle {\text{dist}}_{oneway}={\frac {c't_{r}}{2}}}
62:
2603:
The design constraint that drives this requirement is the
2619:
A sample of the transmit signal leaking into the receiver
1639:{\displaystyle \mathrm {B} ={\frac {f_{\Delta }}{f_{m}}}}
450:{\displaystyle f_{d}=f_{r}-f_{t}=2v{\frac {f_{t}}{c'-v}}}
169:
sets, have a CW function for missile guidance purposes.
1435:{\displaystyle {\text{Range Limit}}=0.5\ c'\ t_{radar}}
73:
Principle of a measurement with a continuous-wave radar
2903:. MIT Radiation Lab series. Vol. 1. p. 629.
2379:
2303:
2084:
1849:
1814:
1661:
1603:
1480:
1384:
1323:
1239:
1201:
1138:
1076:
1024:
980:
885:
834:
811:
784:
691:
559:
514:
466:
371:
265:
130:
The main advantage of CW radar is that energy is not
2824:
1188:{\displaystyle t_{r}={\frac {\Delta {f_{echo}}}{k}}}
229:
Change of wavelength caused by motion of the source
2448:modules and rename them as "Doppler radar sensors"
2407:
2362:
2279:
2067:
1826:
1794:
1638:
1583:
1447:
1434:
1348:
1299:
1214:
1187:
1119:
1054:
1010:
956:
843:
820:
797:
754:
604:{\displaystyle f_{d}\approx 2v{\frac {f_{t}}{c'}}}
603:
542:
500:
449:
351:
2895:
1584:{\displaystyle y(t)=\cos \left\{2\pi t\right\}\,}
138:The military uses continuous-wave radar to guide
3007:
769:
2925:
2923:
220:
209:There are two types of continuous-wave radar:
2920:
2875:. Dover publications Inc. pp. 331ā333.
2408:{\displaystyle {\text{Range}}=0.5C/\delta t}
1062:is the time to complete the frequency sweep.
621:
244:The Doppler frequency change depends on the
2931:"Frequency-Modulated Continuous-Wave Radar"
2768:
2666:signal to noise and a Doppler measurement.
1222:is the round trip time of the radar energy.
1979:
61:
2870:
2765:, 2nd ed., SciTech Publishing, 584 pages.
2276:
2064:
1791:
1580:
677:, like police siren in the United Kingdom
627:Frequency-modulated continuous-wave radar
176:Transmit energy density (watts per Hertz)
2439:
1451:
1120:{\displaystyle \Delta {f_{echo}}=t_{r}k}
1018:is the radar frequency sweep amount and
773:
671:, like police siren in the United States
224:
866:With the advent of modern electronics,
252:is slightly slower than in vacuum) and
3008:
2947:
2705:by wavelength, which is 0.02 meter at
2639:
2622:A sample of the actual transmit signal
2528:. The transmit antenna also issues an
89:system where a known stable frequency
50:
3001:Fairly modern invention mechanization
2615:The null approach takes two signals:
2524:the target in much the same way as a
1364:n (n=1 in vacuum and 1.0003 for air).
43:
36:
2807:. Federation of American Scientists.
1471:The time domain formula for FM is:
29:
13:
2319:
2221:
2124:
2014:
1899:
1711:
1619:
1605:
1530:
1155:
1077:
1055:{\displaystyle \Delta {t_{radar}}}
1025:
1011:{\displaystyle \Delta {f_{radar}}}
981:
924:
895:
835:
812:
508:, it is possible to simplify with
14:
3027:
2994:
2435:
2420:Doppler CFAR detection processing
2974:. MPH Industries. Archived from
1461:into range measurement process.
645:transmitted signal to produce a
22:
2744:
2734: ā Type of radar equipment
2700:This is a typical problem with
2675:Pulse-Doppler radar performance
1448:Sinusoidal frequency modulation
362:The Doppler frequency is thus:
2964:
2907:
2889:
2864:
2850:
2811:
2797:
2763:Introduction to Airborne Radar
2680:
2357:
2348:
2329:
2315:
2268:
2265:
2250:
2231:
2202:
2180:
2171:
2153:
2134:
2094:
2088:
2053:
1997:
1971:
1956:
1953:
1945:
1930:
1882:
1859:
1853:
1783:
1768:
1765:
1757:
1742:
1694:
1671:
1665:
1569:
1513:
1490:
1484:
1127:, rearrange to a more useful:
746:
732:
543:{\displaystyle c'-v\approx c'}
495:
478:
1:
2790:
2673:CW performance is similar to
2656:
2467:
1360:in any transparent medium of
770:Sawtooth frequency modulation
2754:, published by McGraw-Hill,
2740: ā Type of radar system
2551:
2509:This is typically used with
665:, like the chirp from a bird
501:{\displaystyle c',(v\ll c')}
157:family. The launch aircraft
125:
7:
2725:
2497:
872:analog-to-digital converter
221:Unmodulated continuous-wave
211:unmodulated continuous-wave
194:improve range performance.
54:containing much information
10:
3032:
2871:Ditchburn, R. W. (1991) .
2569:
2555:
2306:Modulation Spectrum Spread
2915:"Improved forms of radar"
2752:Frequency Modulated Radar
2630:
1827:{\displaystyle \delta t=}
868:digital signal processing
622:Modulated continuous-wave
256:the speed of the target:
215:modulated continuous-wave
197:A CW radar is said to be
2917:. accessdate=2014-01-24.
2901:Radar System Engineering
2836:10.1109/TIM.2020.2984415
2594:semi-active radar homing
2564:semi-active radar homing
2511:semi-active radar homing
844:{\displaystyle \Delta f}
821:{\displaystyle \Delta t}
204:
140:semi-active radar homing
2858:"Continuous-wave Radar"
2805:"Continuous-wave Radar"
2610:
56:about the backscatterer
2662:missile illumination.
2515:surface-to-air missile
2485:surface-to-air missile
2449:
2427:fast Fourier transform
2409:
2364:
2281:
2069:
1828:
1796:
1640:
1585:
1457:
1436:
1350:
1349:{\displaystyle c'=c/n}
1301:
1216:
1189:
1121:
1056:
1012:
958:
852:
845:
822:
799:
756:
605:
544:
502:
451:
353:
230:
2713:Side-lobe suppression
2520:The transmit antenna
2443:
2410:
2365:
2292:Carson bandwidth rule
2282:
2070:
1829:
1797:
1641:
1586:
1455:
1437:
1351:
1302:
1217:
1215:{\displaystyle t_{r}}
1190:
1122:
1057:
1013:
959:
846:
823:
800:
798:{\displaystyle f_{D}}
777:
757:
659:, like air raid siren
606:
545:
503:
452:
354:
228:
79:Continuous-wave radar
52:backscattered energy,
2978:on 19 September 2011
2959:IEEE Sensors Journal
2769:Jesse Zheng (2005).
2377:
2301:
2082:
1847:
1812:
1659:
1601:
1478:
1382:
1321:
1237:
1199:
1136:
1074:
1022:
978:
883:
832:
809:
782:
743:Modulation Frequency
689:
557:
512:
464:
369:
263:
2860:. Radartutorial.eu.
2761:Stimson, George W.
2738:Pulse-Doppler radar
2640:Interruption, FMICW
144:air-to-air missiles
2758:, 1949, 466 pages.
2750:Luck, David G. C.
2695:antenna side-lobes
2450:
2405:
2360:
2277:
2065:
1824:
1792:
1646:(modulation index)
1636:
1581:
1458:
1432:
1346:
1297:
1212:
1185:
1117:
1052:
1008:
954:
853:
841:
818:
795:
752:
694:Instrumented Range
601:
540:
498:
447:
349:
231:
2897:James M. Ridenour
2677:for this reason.
2538:feed-through null
2480:Feed-through null
2383:
2307:
1634:
1409:
1398:
1388:
1295:
1244:
1183:
952:
750:
744:
730:
695:
599:
445:
343:
3023:
2988:
2987:
2985:
2983:
2968:
2962:
2951:
2945:
2944:
2942:
2941:
2927:
2918:
2911:
2905:
2904:
2893:
2887:
2886:
2868:
2862:
2861:
2854:
2848:
2847:
2815:
2809:
2808:
2801:
2786:
2702:radar speed guns
2693:With 20 dB
2474:monostatic radar
2455:monostatic radar
2414:
2412:
2411:
2406:
2398:
2384:
2381:
2369:
2367:
2366:
2361:
2341:
2340:
2322:
2308:
2305:
2286:
2284:
2283:
2278:
2275:
2271:
2249:
2248:
2224:
2195:
2194:
2152:
2151:
2127:
2074:
2072:
2071:
2066:
2063:
2059:
2052:
2048:
2044:
2043:
2017:
2009:
2008:
1978:
1974:
1952:
1948:
1929:
1928:
1902:
1894:
1893:
1833:
1831:
1830:
1825:
1801:
1799:
1798:
1793:
1790:
1786:
1764:
1760:
1741:
1740:
1714:
1706:
1705:
1645:
1643:
1642:
1637:
1635:
1633:
1632:
1623:
1622:
1613:
1608:
1590:
1588:
1587:
1582:
1579:
1575:
1568:
1564:
1560:
1559:
1533:
1525:
1524:
1441:
1439:
1438:
1433:
1431:
1430:
1407:
1406:
1396:
1389:
1386:
1362:refractive index
1355:
1353:
1352:
1347:
1342:
1331:
1306:
1304:
1303:
1298:
1296:
1291:
1290:
1289:
1280:
1271:
1266:
1265:
1245:
1242:
1221:
1219:
1218:
1213:
1211:
1210:
1194:
1192:
1191:
1186:
1184:
1179:
1178:
1177:
1176:
1153:
1148:
1147:
1126:
1124:
1123:
1118:
1113:
1112:
1100:
1099:
1098:
1061:
1059:
1058:
1053:
1051:
1050:
1049:
1017:
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1014:
1009:
1007:
1006:
1005:
963:
961:
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953:
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949:
948:
922:
921:
920:
919:
893:
850:
848:
847:
842:
827:
825:
824:
819:
804:
802:
801:
796:
794:
793:
761:
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758:
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394:
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358:
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355:
350:
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344:
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333:
318:
317:
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294:
288:
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275:
274:
187:Frequency domain
155:Standard missile
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26:
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3025:
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2969:
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2961:, No. 99, 2015.
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2793:
2783:
2747:
2728:
2683:
2659:
2642:
2633:
2613:
2572:
2560:
2558:Monopulse radar
2554:
2530:omnidirectional
2513:including most
2500:
2470:
2438:
2394:
2380:
2378:
2375:
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2123:
2110:
2106:
2083:
2080:
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2039:
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2028:
2024:
2013:
2004:
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1990:
1986:
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989:
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772:
741:
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692:
690:
687:
686:
642:continuous wave
631:radar altimeter
624:
591:
585:
581:
579:
564:
560:
558:
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532:
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513:
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487:
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91:continuous wave
85:) is a type of
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2996:
2995:External links
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2556:Main article:
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2504:bistatic radar
2499:
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2461:bistatic radar
2437:
2436:Configurations
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1358:speed of light
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1327:
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851:) at any time.
840:
837:
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792:
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771:
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763:
762:
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740:
737:
734:
729:Speed of Light
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246:speed of light
235:Doppler effect
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146:, such as the
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98:Doppler effect
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2935:Radartutorial
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2882:0-486-66667-0
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2830:: 7422ā7436.
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2760:
2757:
2756:New York City
2753:
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2739:
2736:
2733:
2732:Doppler radar
2730:
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2605:dynamic range
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673:
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669:Triangle wave
667:
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663:Sawtooth wave
661:
658:
655:
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650:
648:
643:
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616:line of sight
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167:pulse Doppler
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151:AIM-7 Sparrow
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119:early-warning
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2980:. Retrieved
2976:the original
2966:
2954:
2949:
2938:. Retrieved
2934:
2913:Jim Lesurf.
2909:
2900:
2891:
2872:
2866:
2852:
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2823:
2813:
2799:
2775:. Springer.
2771:
2762:
2751:
2745:Bibliography
2721:
2718:
2711:
2699:
2692:
2688:
2684:
2672:
2668:
2664:
2660:
2651:
2647:
2643:
2636:70 dB.
2634:
2625:
2614:
2602:
2598:
2591:
2588:Interruption
2577:
2573:
2561:
2546:
2542:
2534:
2526:search light
2521:
2519:
2508:
2501:
2493:
2489:
2478:
2471:
2459:
2453:
2451:
2431:
2424:
2417:
2289:
1839:
1651:
1470:
1466:
1463:
1459:
1371:
1227:
1069:
865:
858:
854:
764:
680:
651:
639:
626:
625:
613:
459:
361:
253:
249:
248:in the air (
243:
232:
214:
210:
208:
198:
196:
192:
185:
182:
171:
158:
137:
129:
109:
102:
82:
78:
77:
2982:7 September
2972:"Ranger EZ"
2681:Limitations
2522:illuminates
2446:transceiver
1387:Range Limit
675:Square wave
647:beat signal
163:radio waves
159:illuminates
38:transmitted
32:Transmitter
2940:2012-08-07
2791:References
2657:Advantages
2468:Monostatic
1834:time delay
635:wave radar
2844:216338273
2552:Monopulse
2487:systems.
2400:δ
2352:δ
2346:
2310:≈
2260:δ
2238:π
2229:
2218:π
2212:δ
2197:δ
2184:π
2178:
2166:δ
2141:π
2132:
2121:π
2112:−
2104:
2098:≈
2033:π
2022:
1995:π
1984:
1966:δ
1940:δ
1918:π
1907:
1880:π
1869:
1816:δ
1778:δ
1752:δ
1730:π
1719:
1692:π
1681:
1620:Δ
1549:π
1538:
1511:π
1500:
1156:Δ
1078:Δ
1026:Δ
982:Δ
925:Δ
896:Δ
836:Δ
813:Δ
739:×
711:−
657:Sine wave
571:≈
530:≈
524:−
485:≪
439:−
396:−
324:−
126:Operation
3010:Category
2899:(1947).
2726:See also
2649:begins.
2532:sample.
2498:Bistatic
1404:′
1329:′
1278:′
1195:, where
861:baseband
596:′
550: :
537:′
520:′
492:′
472:′
435:′
339:′
315:′
153:and the
83:CW radar
46:Receiver
2953:M. Ash
2707:Ku band
2570:Leakage
1356:is the
199:matched
142:(SARH)
117:Costly
105:clutter
2955:et al.
2879:
2842:
2779:
2631:Filter
2585:Filter
2458:, and
1808:where
1597:where
1408:
1397:
1317:where
1070:Then,
974:where
239:NASCAR
132:pulsed
40:energy
3016:Radar
2873:Light
2840:S2CID
2382:Range
205:Types
94:radio
87:radar
2984:2011
2877:ISBN
2777:ISBN
2611:Null
2582:Null
2290:The
1243:dist
213:and
148:U.S.
2832:doi
2389:0.5
2343:sin
2226:cos
2175:sin
2129:sin
2101:cos
2019:cos
1981:cos
1904:cos
1866:cos
1716:cos
1678:cos
1535:cos
1497:cos
1394:0.5
3012::
2933:.
2922:^
2838:.
2828:69
2826:.
2822:.
2566:.
2476:.
2464:.
217:.
2986:.
2943:.
2885:.
2846:.
2834::
2785:.
2403:t
2396:/
2392:C
2386:=
2358:)
2355:t
2349:(
2338:m
2334:f
2330:)
2327:1
2324:+
2320:B
2316:(
2313:2
2273:}
2269:)
2266:)
2263:t
2257:+
2254:t
2251:(
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2222:B
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2169:t
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2135:(
2125:B
2118:t
2115:4
2108:{
2095:)
2092:t
2089:(
2086:y
2061:}
2057:t
2054:]
2050:)
2046:t
2041:m
2037:f
2030:2
2026:(
2015:B
2011:+
2006:c
2002:f
1998:[
1992:2
1988:{
1976:}
1972:)
1969:t
1963:+
1960:t
1957:(
1954:]
1950:)
1946:)
1943:t
1937:+
1934:t
1931:(
1926:m
1922:f
1915:2
1911:(
1900:B
1896:+
1891:c
1887:f
1883:[
1877:2
1873:{
1863:=
1860:)
1857:t
1854:(
1851:y
1822:=
1819:t
1788:}
1784:)
1781:t
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1772:t
1769:(
1766:]
1762:)
1758:)
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1723:(
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1708:+
1703:c
1699:f
1695:[
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1685:{
1675:=
1672:)
1669:t
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1610:=
1606:B
1577:}
1573:t
1570:]
1566:)
1562:t
1557:m
1553:f
1546:2
1542:(
1531:B
1527:+
1522:c
1518:f
1514:[
1508:2
1504:{
1494:=
1491:)
1488:t
1485:(
1482:y
1428:r
1425:a
1422:d
1419:a
1416:r
1412:t
1401:c
1391:=
1344:n
1340:/
1336:c
1333:=
1326:c
1293:2
1287:r
1283:t
1275:c
1268:=
1263:y
1260:a
1257:w
1254:e
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1248:o
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1174:o
1171:h
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1165:e
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1150:=
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1106:t
1102:=
1096:o
1093:h
1090:c
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1044:a
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1038:a
1035:r
1031:t
1003:r
1000:a
997:d
994:a
991:r
987:f
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943:a
940:d
937:a
934:r
930:t
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911:d
908:a
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901:f
890:=
887:k
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816:t
791:D
787:f
747:)
736:4
733:(
724:=
719:t
715:F
706:r
702:F
698:=
593:c
587:t
583:f
577:v
574:2
566:d
562:f
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527:v
517:c
496:)
489:c
482:v
479:(
476:,
469:c
442:v
432:c
425:t
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412:2
409:=
404:t
400:f
391:r
387:f
383:=
378:d
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346:)
336:c
331:/
327:v
321:1
312:c
307:/
303:v
300:+
297:1
291:(
285:t
281:f
277:=
272:r
268:f
254:v
81:(
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