Duty (%) 30 30 30 Range compression ratio 60 000 60 000 60 000 Antenna type Planar Planar array Planar array Antenna peak gain (dBi) 47.0 47.0 47.0 e.i.r.p. (dBW) 85.5 85.5 85.5 Antenna orientation from Nadir 18.5° to 49.3° 18.5° to 49.3° 18.5° to 49.3° Antenna beamwidth 1.13° (El) 0.53° (Az) 1.13° (El) 0.53° (Az) 1.13° (El) 0.53° (Az) TABLE 3 (end) Parameter SAR-4/700 SAR-4/900 SAR-4/1100 Antenna polarization Linear horizontal/vertical Linear horizontal/vertical Linear horizontal/vertical System noise temperature (K) 500 500 500 * Final value depends on the decision eventually taken under WRC-15 agenda item 1.12 3.2 Comparison of interference conditions under peak I/N The peak interference signal power level received by terrestrial radar from a spaceborne SAR is calculated with equations 1, 4a and 4b given in . where: Pt: peak spaceborne sensor transmitter (W) Gt: spaceborne sensor antenna gain towards terrestrial radar (dB) Gr: terrestrial radar antenna gain towards spaceborne sensor (dBi) F: frequency (MHz) R: range between sensor and radar (km) OTR: receiver on-tune rejection (dB) gain (dB), rejection of unwanted signals due to radar receiver signal processing (assumed to be zero if not known) N: receiver inherent noise level (dBW). N = –204 dBW + 10 log (Br) + NF where: Br: receiver IF bandwidth (Hz) noise figure (dB). The on-tune rejection term is calculated as: OTR 0 for Bc / (Br2 T) 1 OTR 10 · log (Br2 T /Bc) for Bc / (Br2 T) 1
TABLE 8 Characteristics of radionavigation radars in the frequency range 8 700-9 300 MHz Characteristics Unit System G5 System G6 System G7 System G8 System S14 System G21 System G22 Function Precision approach and landing radar Airport surveillance GCA Precision approach radar Airport surface detection equipment Surveillance (vessel and coastal) Airport surface detection equipment Airport surface detection equipment Tuning range MHz 9 000-9 200 9 025 9 000-9 200 (4 frequencies /system) 9 000-9 200 Pulse to pulse agile over 4 frequencies 9 000-9 200 or 9 225-9 300 9 000-9 200; agile over 16 frequencies predefined hopping 9 000-9 200; agile over 4 frequencies predefined hopping Modulation pulse Plain, NLFM Plain NLFM pulse pair and LFM pulse pairs V7N Fully coherent pulse compression radar using complex pattern of chirps at up to 6 centre frequencies with three different chirp durations Plain and LFM pulse pairs Two LFM pulses define a pulse pair Peak power kW 120 0.3105 0.5 0.07 0.05-0.1 170 50 Pulse widths μs 0.25 1.2; 30; 96 0.65 and 25 pulse-pair 0.04 and 4.0 (compressed to 0.040) 0.150 to 40 0.040 and 4.0 (compressed to 0.040) 10.0 and 0.15 at 7 500 (both compressed to 0.040); Pulse repetition rate pps 6 000 12 800; 3 2006 300; 2 120 3 470; 3 500; 5 200; 5 300 4 096 each, 8192 total 1000 – 5000 16 384 each System maximum average 15 000 Max. duty cycle 0.0015 0.203 0.11 0.017 0.2 0.07 0.15
TABLE 8 (continued) Characteristics Unit System G5 System G6 System G7 System G8 System S14 System G21 System G22 Pulse rise times s 0.02 0.15 Short pulse: 0.016 Long 0.082 ~0.02 Short pulse: 0.016 Long pulse: 0.038 Short pulse: 0.020 Long pulse: 0.020 Pulse fall times μs 0.04 0.15 Short pulse: 0.018 Long pulse: 0.06 ~0.02 Short pulse: 0.023 Long 0.056 pulse: 0.020 Long pulse: 0.020 Antenna pattern type Pencil/fan Fan (csc²) Vertical fan and horizontal fan Inverse csc² Fan beam Inverse csc2 Inverse csc2 Antenna type Planar array Active array plus reflector Two phased arrays Passive array Slotted waveguide Passive array Slotted waveguide Antenna polarisation Circular Vertical Right-hand circular circular horizontal Right hand circular circular Main beam gain dBi 40 37.5 (Tx) 37.0 (Rx) Vertical fan: 36 Horizontal fan: 36 35 ≥ 34 37.6 37.6 Elev. beamwidth ° 0.7 3.5 + csc² to 20 Vertical fan: 9.0 Horizontal fan: 0.63 19 ≤ 16º @ −3dB / ≤ 55º @ −20dB 9.91 9.91 Azim. beamwidth ° 1.1 1.05 Vertical fan: 1.04 Horizontal fan: 15 0.35 ≤ 0.6º @ −3dB 0.37 0.37 Horiz. scan rate °/s 5-30 12 Vertical fan: 60, half time (60 360 10-48 rpm 360 360
TABLE 8 (end) Characteristics Unit System G5 System G6 System G7 System G8 System S14 System G21 System G22 Total chirp width MHz 0.8 estimated 2 pulse: none; Long pulse: 50 80 ns to 100 μs – medium, long (to be clarified) pulse : none Long pulse : 50 Short pulse : 35 Long pulse : 35 RF emission bandwidth 3 dB MHz 3.6 0.8 estimated 1.1 pulse), 1.8 (non˗linear frequency modulation (NLFM)) 43.2 Depending on profiles Normally the full band is used so the −20dB BW stays within the band 9 225- 9 500 GHz and the –3 dB BW is the combined BW of all center frequencies used. Default individual chirp –3dB BW is 35MHz. 50 35 RF emission bandwidth 20 dB MHz 25 Unknown 5.8 (plain pulse), 3.15 (NLFM) 70.3 59 42
58 Simulation results of interference criteria to pulse radars Simulation result of radar A12 Simulation result of radar G20 TABLE 21 Simulation calculation results of interference criteria for pulse radars Type of radar Pulse width (μs) Repeat period (μs) Bandwidth (MHz) Pj-av (dBm) Pj-peak (dBm) N (dBm) A12 15 20 4 –76.7 –71.5 –102 30.5 28.7 0.5 24 30 4 –72 –66.8 35.2 33.4 5.2 G20 15 50 4 –71.3 –66.1 –102 35.9 34.1 5.9 30 50 4 –69 –64 37.8 36.0 7.8 4.2.3.2.5 Summary of results of 2 The analysis of interference simulations from EESS SAR-4 to pulse radars indicates that: – the interference level keeps basically constant when the repeat period of SAR pulse increasing, while the decreasing appearance times of interference pulse will reduce the average interference power; – the interference level rises with the increasing pulse width of SAR interference signals, which also raises the average interference power; – the wanted radar signals decreases when the bandwidth of SAR signal increases, and the interference effect becomes weaker; – the pulse repetition frequency of radar does not affect the amplitude of received interference signals from SAR, and the duration of interference is in proportion to the pulse repetition frequency of the radar; – the amplitude of pulse radar received from SAR interference signals decreases with the increase of pulse width of pulse radar, and the interference rejection capability is also enhanced. Simulations of interference for pulse radars indicate that: – when the pulse width of radar A12 is 15 μs and 24 μs, the allowable maximum ratio of average interference to noise power is 0.5 dB and 5.2 dB, respectively, and the allowable maximum ratio of peak interference to noise power is 28.7 dB and 33.4 dB, respectively; – when the pulse width of radar G20 is 15 μs and 30 μs, the allowable maximum ratio of average interference to noise power is 5.9 dB and 7.8 dB respectively, and the allowable maximum ratio of peak interference power to noise power is 34.1 dB and 36 dB, respectively.