Radar – Principle / Type / Limitation / Error / Setup

Radar – Radio Detection and Ranging.

Principle: it Works on Echo Principle (Echo ranging by radar) which is based on time interval between the transmission of an EM pulse into the environment and reception of its echo.

  • Instead of Sound wave it uses Radio waves.
  • Radar transmission causes an electro-magnetic vibration which travels through air @300 m/per micro sec. [1,000,000 = 1 Sec]

Type:

·         X Band 3cm, 9 GHZ ·         S Band 10 cm, 3 GHZ
·         Can detect SART ·         Better Target detecting in RAIN
·         In fair weather target will show better ·         Better for long range detection (radar horizon greater than 9 GHZ
·         For high discrimination, good sensitivity and tracking performance. ·         Good sea clutter response, tgt less likely to be hidden.
·         Better for and Rain clutter.
·         Short Antenna ·         Large Antenna

 

Carriage Requirement: Min Radar/ARPA requirements [SOLAS Ch 5 – Annex 16]

Gross Tonnage 9 GHZ  X Band 3 GHZ S Band EPA ATA ARPA
300 – 500 1 1
> 500 – < 3000 1 1
3000 – 10000 1 1* 2
10000 + 1 1* 1** 1

* Can be 9 GHZ, if administration consider it appropriate.
– MCA require reason why 3 GHZ Radar cannot be carried.

** Instead of APA it can be 2nd ARPA.

Performance Requirement:

Size of Ship < 500 GT 500 < 10000 GT ( HSC < 10k GT) All Ships 10000 GT and above
Min ops display area 180 mm 250 mm 320 mm
Min Display area 195 mm x 195 mm 270 mm x 270 mm 340 mm x 340 mm
Auto ACQ of target Yes
Min ACQ Radar target cap 20 30 *40
Min Activated AIS tgt cap 20 30 40
Min Sleeping AIS tgt cap 100 150 200
Trial Manoeuvre Yes

*Solas 8.6.3.1 Atleast 20 target can be acquired both manually ???

Limitations:

Ajit Tiwari is an sailing Second Officer and the founder of iMariners.com. He specializes in practical bridge operations and ECDIS management, developing digital tools that help fellow Navigating Officers streamline onboard workflows and navigate maritime regulations safely and efficiently.