001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.math3.filter;
018
019import org.apache.commons.math3.linear.RealMatrix;
020
021/**
022 * Defines the measurement model for the use with a {@link KalmanFilter}.
023 *
024 * @since 3.0
025 * @version $Id: MeasurementModel.java 1416643 2012-12-03 19:37:14Z tn $
026 */
027public interface MeasurementModel {
028    /**
029     * Returns the measurement matrix.
030     *
031     * @return the measurement matrix
032     */
033    RealMatrix getMeasurementMatrix();
034
035    /**
036     * Returns the measurement noise matrix. This method is called by the {@link KalmanFilter} every
037     * correction step, so implementations of this interface may return a modified measurement noise
038     * depending on the current iteration step.
039     *
040     * @return the measurement noise matrix
041     * @see KalmanFilter#correct(double[])
042     * @see KalmanFilter#correct(org.apache.commons.math3.linear.RealVector)
043     */
044    RealMatrix getMeasurementNoise();
045}