6.3
SEA CLUTTER AND RAIN AND SNOW
CLUTTER
In addition to the echo required for observing ships and land radar video image also includes unnecessary
echo, such as reflection from waves on the sea surface and reflection from rain and snow. Reflection from
the sea surface is called "sea clutter," and reflection from rain and snow is called "rain and snow clutter,"
and those spurious waves must be eliminated by the clutter rejection function.
[I] Sea
clutter
Sea clutter appears as an image radiating outwardly from the center of the radar display and changing
depending on the size and the shape of waves. Generally, as waves become larger, image level of the
sea clutter is intensified and the clutter far away is also displayed. When waves are large and the sea
clutter level is high, it is difficult to distinguish sea clutter from a small boat whose reflection intensity
is weak. Accordingly, it is necessary to properly adjust the sea clutter rejection function. Table 6.2
shows the relation between the sea state (SS) showing the size of waves generated by wind and the
radar's detection probability.
Table 6.2 Sea state and probability of target detection
RCS
SS1 to 2
SS2 to 3
SS3 to 4
SS4 to 5
0.1m
2
V V-M
M-NV
0.5 m
2
V V
V-M
M-NV
1 m
2
V V V
V-M
S band radar (probability to detect a target at a distance of 0.4 NM)
RCS
SS1 to 2
SS2 to 3
SS3 to 4
SS4 to 5
1m
2
V-M M-NV
5 m
2
V V-M
M-NV
10 m
2
V V V
V-M
X band radar (probability to detect a target at a distance of 0.7 NM)
V:
Detection probability of 80 %
M: Detection probability of 50 %
NV: Detection probability of less than 50 %
6-5
Summary of Contents for JMA-5912-6
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Page 17: ...xi NKE 2103 6 Scanner Unit NKE 2254 7 9 Scanner Unit Warning Label Warning Label...
Page 18: ...xii NKE 1130 Scanner Unit NQE 3151A Junction Box Warning Label Warning Label...
Page 19: ...xiii NQE 3141 4A 8A Interswitch Unit NBA 5111 Power Supply Warning Label Warning Label...
Page 20: ...xiv NQE 3167 Power Control Unit Warning Label...
Page 22: ...xvi Scanner Unit Type NKE 2254 9 9 feet NDC 1477 Radar Process Unit Desktop Type...
Page 23: ...xvii NWZ 170 Monitor Unit Desktop Type NCE 5171 Operation Unit Desktop Type...
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Page 49: ...1 8 1 4 Exterior Drawings y 1 Fig 1 2 Outside Drawing of NKE 2254 7 SCANNER UNIT...
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Page 51: ...1 10 1 4 Exterior Drawings y 1 Fig 1 4 Outside Drawing of NKE 1130 SCANNER UNIT...
Page 52: ...1 11 Fig 1 5 Outside Drawing of NWZ 170 MONITOR UNIT Option...
Page 54: ...1 13 Fig 1 7 Outside Drawing of NDC 1477 RADAR PROCESS UNIT...
Page 55: ...1 14 1 4 Exterior Drawings y 1 Fig 1 8 Outside Drawing of NCE 5171 OPERATION UNIT...
Page 56: ...1 15 Fig 1 9 Outside Drawing of NQE 3151A JUNCTION BOX...
Page 57: ...1 16 1 4 Exterior Drawings y 1 Fig 1 10 Outside Drawing of NQE 3141 4A INTERSWITCH UNIT Option...
Page 58: ...1 17 Fig 1 11 Outside Drawing of NQE 3141 8A INTERSWITCH UNIT Option...
Page 60: ...1 19 Fig 1 13 Outside Drawing of NQE 3167 POWER CONTROL UNIT Option...
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Page 421: ...APPENDIX...
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Page 438: ...32bit bus BP BZ VD TI MTR PWRCNT P12V 12V RGB Fig 2 Block Diagram of JMA 5932 12 RADAR...
Page 442: ...Fig 6 Terminal Board Connection Diagram of RADAR and INTERSWITCH Unit Option...
Page 443: ...Fig 7 Power System Diagram of JMA 5912 6 JMA 5922 7 9 RADAR...
Page 445: ...Fig 9 Internal Connection Diagram of NDC 1477 RADAR PROCESS UNIT...
Page 446: ...Fig 10 Internal Connection Diagram of NQA 2123 INTERFACE UNIT...
Page 447: ...Fig 11 Internal Connection Diagram of NCE 5171 OPERATION UNIT...
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