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This package supports the parsing of AIS messages in Java. AIS, the Automatic Identification System, is a system aiming at improving maritime safety by exchanging messages between ships, other vehicles in particular aircraft involved in search-and-rescue (SAR), and (fixed) base stations. To be precise, this package support the ITU-R M.1371-4 AIS standard. See our extensive javadoc and in particular the class AISParser for more information on how to use this package. The parser was used in the Poseidon project, and is improved in the Metis project to better handle uncertain information. Both projects were led by the Embedded Systems Institute. In both projects Thales Nederlands was the carrying industrial partner, and multiple Dutch universities participated.

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package nl.esi.metis.aisparser.impl;

import nl.esi.metis.aisparser.AISMessage02;
import nl.esi.metis.aisparser.Sixbit;
import nl.esi.metis.aisparser.Sotdma;
import nl.esi.metis.aisparser.provenance.VDMMessageProvenance;
/** ESI AIS Parser
 * 
 * Copyright 2011/2012 by Pierre van de Laar (Embedded Systems Institute)
 * Copyright 2008 by Brian C. Lane 
 * All Rights Reserved
 * 
 * @author Pierre van de Laar
 * @author Brian C. Lane
 */

//TODO should we exploit that AIS Message 1 and 2 are identical (both SOTDMA)?

/** AIS Message 2 implementation: Position report.
 *  * Field Nr     Field Name                          NrOf Bits   (from, to )
 * ------------------------------------------------------------------------
 *  1	messageID                               	   6	(   1,   6)
 *  2	repeatIndicator                         	   2	(   7,   8)
 *  3	userID                                  	  30	(   9,  38)
 *  4	navigationalStatus                      	   4	(  39,  42)
 *  5	rateOfTurn                              	   8	(  43,  50)
 *  6	speedOverGround                         	  10	(  51,  60)
 *  7	positionAccuracy                        	   1	(  61,  61)
 *  8	longitude                               	  28	(  62,  89)
 *  9	latitude                                	  27	(  90, 116)
 * 10	courseOverGround                        	  12	( 117, 128)
 * 11	trueHeading                             	   9	( 129, 137)
 * 12	timeStamp                               	   6	( 138, 143)
 * 13	specialManoeuvre                        	   2	( 144, 145)
 * 14	spare                                   	   3	( 146, 148)
 * 15	raimFlag                                	   1	( 149, 149)
 * 16	communicationState                      	  19	( 150, 168)
 *                                                      ---- +
 *                           (maximum) number of bits    168
 * 
 */
class AISMessage02Impl extends AISMessagePositionReportImpl implements AISMessage02 {
	
	private Sotdma communicationState;
	/** communicationState
	 * @return Sotdma value of communicationState (19 bits [150,168])
	 */
	public Sotdma getCommunicationState() { return communicationState; }
	
	/** AISMessage 2 constructor
	 * @param content AIS content
	 * @param prov the provenance of the message
	 * @precondition validLength(content.length()) && AISMessageBase.getMessageId(content)== 2
	 */
	public AISMessage02Impl(Sixbit content, VDMMessageProvenance prov)
	{
		super(content, prov);
		assert(getMessageID() == 2);
    	communicationState = new Sotdma(COMMUNICATIONSTATE_FROM, content);
	}
}