Effective Jam Power
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| Equation: PJeff = PJ x GJ (Watt) |
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Examble: PJ = 200 Watt GJ = 6 dB (4) 200 x 4 = 800 Watt |
| If BWR < then BWJ then PJeff = PJ x (BWR / BWJ) |
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If BWR |
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BWR = Bandwidth Radar BWJ = Jamming Bandwidth Jammer PJeff = Effective Jamming Power |
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Jam Power at the RADAR Receiver Input
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| Equation: JPr = ((PJ x GJ x GR x lam2 x BWR) / ((4 x pi)2 x R2J x BWJ x L)) |
| JPr = Jam Power at Receiver (Watt) |
| PJ = Jammer Transmitted Power (Watt) |
| GJ = Antenna Gain Jammer (Figure) |
| GR = Antenna Gain Radar (Figure) |
| lam = Wavelength (m) |
| BWR = IF Bandwidth Radar (Hz) |
| RJ = Range to Jammer (m) |
| BWJ = Jamming Bandwidth |
| L = Losses |
| BWR and BWJ are matched no Losses! |
| PJ GJ GR lam2 BWR pi 230 km BWJ L |
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JPr = (200 x 4 x 3162 x 0.0083266 x 1) / (158 x 5.2910 x 1 x 1) = 2.5-9 Watt or - 86 dBW |
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Jam Power of a Jamming Source
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| Equation: PJ = (JPr x (4 x pi)2 x R2J x BWJ x L) / ( GJ x GR x lam2 x BWR) |
| PJ = Jammer Transmitted Power (Watt) |
| JPr = Jam Power at Receiver Input (Watt) |
| RJ = Range to Jamming Source (m) |
| BWJ = Jamming Bandwidth (Hz) |
| L = Losses (Figure) |
| GJ = Antenna Gain Jammer (Figure) |
| GR = Antenna Gain Radar (Figure) |
| lam = Wavelength (m) |
| BWR = IF Bandwidth Radar (Hz) |
| JPr pi 50km BWJ 19dB 6dB 44dB 0.033 BWR |
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PJ = (7.08-10 x 158 x 2.59 x 16 x 79) / (4 x 25119 x 1.09-3 x 16) = 201.73 Watt |
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Self-Screening Range
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| Equation: RSS = ((PR x GR x sig x BWJ x GP) / (PJ x GJ x 4 x pi x BWR x S/N))0.5 |
| RSS = Range Self Screening (m) |
| PR = Radar Transmitted RF Power (Watt) |
| GR = Radar Antenna Gain (Figure, LOPAR Pencil Beam) |
| sig = Radar Cross Section of Jammer (sq. m) |
| BWJ = Bandwidth of Jamming (Hz) |
| Gp = Gain Processing (MTI, Integration etc.) |
| PJ = Transmitted Jamming Power (Watt) |
| GJ = Antenna Gain of Jammer |
| BWR = IF Bandwidth of Radar |
| S/N = Necessary Signal to Noise Ratio |
| PR GR sig BWJ GP PJ GJ BWR S/N |
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RSS = (( 1 000 000 x 3162 x 3 x 16 x 1 ) / ( 200 x 4 x 12.57 x 16 x 1 ))0.5 = 971 m |
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Under the above conditions the LOPAR could not detect the target early enough for an engagement! |
Diagram Self Screening Range
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| Variables | TTR SP | TTR LP | LOPAR | HIPAR |
| Pav | 28 | 280 | 500 | 26000 |
| G | 44 | 44 | 35 | 34.8 |
| RCS | 10 | 10 | 10 | 10 |
| Td | 100 | 100 | 22 | 19 |
| Loss Jammer | 6 | 6 | 6 | 6 |
| S/N | 3 | 3 | 3 | 3 |
| Loss Radar | 22 | 22 | 20 | 18 |
| G Jammer | 6 | 6 | 6 | 6 |
| BW Radar (MHz) | 10 | 1 | 1 | .3 |
DIAGRAM
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MutualScreening Range
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Equation: RS = (( PR x GR x GR x sig x R2J x BWJ x GP) / (PJ x GJ x GRJ x 4 x pi x BWR x S/N x L))0.25 | ||||
| RS = Range Screening (m) | ||||
| PR = Radar Transmitted RF Power (Watt) | ||||
| GR = Radar Antenna Gain (Figure, LOPAR Pencil Beam) | ||||
| sig = Radar Cross Section of Jammer (sq. m) | ||||
| R = Range to Jammer (m) | ||||
| BWJ = Bandwidth of Jamming (Hz) | ||||
| Gp = Gain Processing,MTI, Integration etc.. (Figure) | ||||
| PJ = Transmitted Jamming Power (Watt) | ||||
| GJ = Antenna Gain of Jammer (Figure) | ||||
| GRJ = Radar Antenna Gain in the Direction of Jammer (Figure) | ||||
| BWR = IF Bandwidth of Radar (Hz) | ||||
| S/N = Necessary Signal to Noise Ratio (Figure) | ||||
| L = Jammer Losses (Figure) | ||||
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Examble: Target will be screened by a Jammer. Target and Jammer are in the main beam of the LOPAR antenna. | ||||
| PR GR x GR sig R2J BWJ GP PJ GJ GRJ BWR S/N L | ||||
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RS = ((1 000 000 x 10 000 000 x 3 x 1.08911 x 16 x 1) / (1 000 x 4 x 3162 x 12.58 x 16 x 1 x 1))0.25 The Target will be visible at = 11 970 m
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Diagram Mutual Screening Range
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| Variables | TTR SP | TTR LP | LOPAR | HIPAR |
| Pav | 28 | 280 | 500 | 26000 |
| G | 44 | 44 | 35 | 34.8 |
| RCS | 10 | 10 | 10 | 10 |
| Dwell Time | 100 | 100 | 22 | 19 |
| BW Jamming (MHz) | 100 | 100 | 100 | 100 |
| Range Jammer (km) | 300 | 300 | 300 | 300 |
| SNR | 3 | 3 | 3 | 3 |
| Loss Radar | 22 | 22 | 20 | 18 |
| G Jammer | 6 | 6 | 6 | 6 |
| BW Radar | 10 | 1 | 1 | .3 |
| G direction of Jammer | 44 | 44 | 35 | 34.8 |
DIAGRAM | ||||
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Chaff
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One CHAFF-UNIT (CU) = 50 sq. m |
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500 Gramm aluminium CHAFF for the F-Band (3 - 4 GHz) consist of 1.37 million Chaff Dipols |
| G-Band (4 -6 GHz) " 2.05 million Chaff Dipols |
| I-Band (8 - 10 GHz) " 4.10 million Chaff Dipols |
Quantity of Chaff Dipols to simulate a specific target. |
| Equation: N = deltaRCS / 0.18 x lam2 |
| N = Number of Dipols |
| deltaRCS = simulated Radar Cross Section (RCS) |
| lam = Wavelength (9.12 cm for the example) |
| deltaRCS 9.122 |
| Example: N = 100 / (0.18 x 0.0083266) = 66 720 Dipols are needed |
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