Requirements of a radar for the Maritime Environment: Captain

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REQUIREMENTS OF A
RADAR FOR THE MARITIME
ENVIRONMENT
By Captain (SA Navy ) Nick Snyman
Senior Staff Officer Maritime Technology
Directorate Technology Development
1
AIM
To provide an operational view of radar
operating conditions in the maritime
environment
2
SCOPE
•
•
•
•
•
Mission of the SA Navy
Maritime environmental conditions
Uses of radar in maritime environment
Operational implications
Conclusion
3
MARITIME ENVIRONMENTAL
CONDITIONS
4
Life at sea is good
5
5
Pretty sights
6
6
Beautiful views for a
submariner
7
7
Lovely day in the sun
and calm seas
8
8
Start dreaming that
life could not be
better
….. And you are expect
to see these sights
9
AND THEN THE REALITY OF SEA LIFE STRIKES!!!!!!!!
10
10
11
11
12
12
13
14
14
MARITIME ENVIRONMENTAL
CONDITIONS (The other side of
life at sea)
RomanRock.wmv
15
16
MARITIME ENVIRONMENTAL
CONDITIONS
• Clutter (Rain and Sea)
– Obscures small contacts
– No clear close range picture
– Danger to vessels in confined space
• Ducting
– Ducting increases clutter and increased
anomalous propagation
– Increased radar range
• Multi-pathing
17
Factors in Radar Equation
Multipath
Sea & Rain Clutter
Clutter
18
Sea Clutter Illumination AREA
θVertical
Area = k(Range)(θH)(τ)(secγ)
θHorizontal
Τ = Pulse Length
19
Sea Clutter (SS=3)
Clutter = 0 > Radar Horizon
20
Rain Clutter Illumination VOLUME
θVertical
Volume = k(Range)2(θH)(θH)(τ)
θHorizontal
Τ = Pulse Length
21
Rain Clutter (1mm/hour)
Clutter = 0 > Radar Horizon
23
Sea & Rain Clutter
Influence on Detectability in Naval Environment
Pd = 32km
FSG
FSG
Pd = 11km
Sea
24
Rain Clutter
Contacts
25
MAGNETRON X-BAND
26
SOLID STATE X-BAND PULSE COMPRESSION
27
X-BAND MAGNETRON
28
SOLID STATE X-BAND PULSE COMPRESSION
29
MARITIME ENVIRONMENTAL
CONDITIONS (1)
• Clutter (Rain and Sea)
– Obscures small contacts
– No clear close range picture
– Danger to vessels in confined space
30
MARITIME ENVIRONMENTAL
CONDITIONS (2)
• Ducting
– Ducting increases clutter and increased
anomalous propagation
– Increased radar range
31
Radar Ducting
Ducted beam
Normal radar beam
32
MARITIME ENVIRONMENTAL
CONDITIONS (3)
• Multi-pathing
– Cannot detect and track low flying targets
– Ineffective radar against fast low flying
incoming missiles
• Effect of side lobe interference in littoral
33
Multipath: Principle of Null & Sum Values
RDirect
RMultipath
θ
θ
Path Difference = λ/2
Path Difference = λ
Direct
Direct
Multipath
Multipath
4x Amplitude
Sum
ZERO
Sum
34
Multipath: Range Holes
35
MARITIME ENVIRONMENTAL
CONDITIONS (4)
• Effect of side lobe interference in littoral
36
SIDE LOBES
37
USES OF MARITIME RADAR
38
USES OF MARITIME RADAR
•
•
Collision avoidance
Navigation and Blind pilotage
– Good range discrimination
– Close range clear picture
– High definition
39
40
41
USES OF MARITIME RADAR
• Surveillance
–
–
–
–
–
–
Long range, early warning
Close-in surveillance
Range discrimination
3D picture
Track while scan
Track multiple contacts
• Small contacts
• Low flying contacts
• Tracking radar
42
OPERATIONAL IMPLICATIONS
43
OPERATIONAL IMPLICATIONS
• Range discrimination to discriminate
between contacts in close proximity
• Lack of detection ability in clutter
– Missing the target
– Own ship detected first
• Require recognition and identification
ability
• Interference from other radars
• Antenna height restrictions
44
Cannot see the spur
45
Interference caused by radar, clutter and
radar shadow
Clutter
Shadow caused by mast
46
Radar Picture of land-based radar
47
CONCLUSION
• Surveillance, detection and identification is
important to the Navy
• Unique maritime environmental conditions
affects radar performance
–
–
–
–
–
Sea conditions - stability
Sea and rain clutter
Ducting
Muti-pathing
Effect of the littoral on the side lobe contacts
• Different types of radar
– Navigation
– Long range surveillance
– Tracking
48
THANK YOU!!
QUESTIONS??
49
Multipath (“Two-way only!”)
50
Sea Surface Reflection: (1) Amplitude ~ 100% (2) Phase = 180%
51
Sea Surface Reflection: Frequency
52
MRR vs SSM: RCS = 0.1m2 @ 15m
SSM
Pd (80%) = 25km
Sea
Sub Clutter Visibility = 48dB
53
Radar Data Reduction
54
SEA TRAFFIC DENSITY AROUND THE WORLD
55
Sea Clutter (AREA Illumination)
m2/m2
m2
56
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