LMedSRobustRangingAndRssiRadioSourceEstimator2D.java
/*
* Copyright (C) 2018 Alberto Irurueta Carro (alberto@irurueta.com)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.irurueta.navigation.indoor.radiosource;
import com.irurueta.geometry.Point2D;
import com.irurueta.navigation.LockedException;
import com.irurueta.navigation.NotReadyException;
import com.irurueta.navigation.indoor.RadioSource;
import com.irurueta.navigation.indoor.RangingAndRssiReadingLocated;
import com.irurueta.numerical.robust.LMedSRobustEstimator;
import com.irurueta.numerical.robust.LMedSRobustEstimatorListener;
import com.irurueta.numerical.robust.RobustEstimator;
import com.irurueta.numerical.robust.RobustEstimatorException;
import com.irurueta.numerical.robust.RobustEstimatorMethod;
import java.util.List;
/**
* Robustly estimate 2D position, transmitted power and path-loss
* exponent of a radio source (e.g. Wi-Fi access point or bluetooth beacon), by discarding
* outliers using LMedS algorithm and assuming that the ranging data is available to
* obtain position with greater accuracy and that the radio source emits isotropically
* following the expression below:
* Pr = Pt*Gt*Gr*lambda^2 / (4*pi*d)^2,
* where Pr is the received power (expressed in mW),
* Gt is the Gain of the transmission antenna
* Gr is the Gain of the receiver antenna
* d is the distance between emitter and receiver
* and lambda is the wavelength and is equal to: lambda = c / f,
* where c is the speed of light
* and f is the carrier frequency of the radio signal.
* Because usually information about the antenna of the radio source cannot be
* retrieved (because many measurements are made on unknown devices where
* physical access is not possible), this implementation will estimate the
* equivalent transmitted power as: Pte = Pt * Gt * Gr.
* If Readings contain RSSI standard deviations, those values will be used,
* otherwise it will be assumed an RSSI standard deviation of 1 dB.
*
* @param <S> a {@link RadioSource} type.
*/
@SuppressWarnings("Duplicates")
public class LMedSRobustRangingAndRssiRadioSourceEstimator2D<S extends RadioSource> extends
RobustRangingAndRssiRadioSourceEstimator2D<S> {
/**
* Default value to be used for stop threshold. Stop threshold can be used to
* avoid keeping the algorithm unnecessarily iterating in case that best
* estimated threshold using median of residuals is not small enough. Once a
* solution is found that generates a threshold below this value, the
* algorithm will stop.
* The stop threshold can be used to prevent the LMedS algorithm iterating
* too many times in cases where samples have a very similar accuracy.
* For instance, in cases where proportion of outliers is very small (close
* to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
* iterate for a long time trying to find the best solution when indeed
* there is no need to do that if a reasonable threshold has already been
* reached.
* Because of this behaviour the stop threshold can be set to a value much
* lower than the one typically used in RANSAC, and yet the algorithm could
* still produce even smaller thresholds in estimated results.
*/
public static final double DEFAULT_STOP_THRESHOLD = 1e-4;
/**
* Minimum allowed stop threshold value.
*/
public static final double MIN_STOP_THRESHOLD = 0.0;
/**
* Threshold to be used to keep the algorithm iterating in case that best
* estimated threshold using median of residuals is not small enough. Once
* a solution is found that generates a threshold below this value, the
* algorithm will stop.
* The stop threshold can be used to prevent the LMedS algorithm iterating
* too many times in cases where samples have a very similar accuracy.
* For instance, in cases where proportion of outliers is very small (close
* to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
* iterate for a long time trying to find the best solution when indeed
* there is no need to do that if a reasonable threshold has already been
* reached.
* Because of this behaviour the stop threshold can be set to a value much
* lower than the one typically used in RANSAC, and yet the algorithm could
* still produce even smaller thresholds in estimated results.
*/
private double stopThreshold = DEFAULT_STOP_THRESHOLD;
/**
* Constructor.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D() {
super();
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings) {
super(readings);
}
/**
* Constructor.
*
* @param listener listener in charge of attending events raised by this instance.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param listener listener in charge of attending events raised by this instance.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(readings, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialPosition initial position to start the estimation of radio
* source position.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition) {
super(readings, initialPosition);
}
/**
* Constructor.
*
* @param initialPosition initial position to start the estimation of radio
* source position.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(final Point2D initialPosition) {
super(initialPosition);
}
/**
* Constructor.
*
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param listener listener in charge of attending events raised by this instance.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final Point2D initialPosition,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(initialPosition, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param listener listener in charge of attending events raised by this instance.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(readings, initialPosition, listener);
}
/**
* Constructor.
*
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's)
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(final Double initialTransmittedPowerdBm) {
super(initialTransmittedPowerdBm);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's)
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
final Double initialTransmittedPowerdBm) {
super(readings, initialTransmittedPowerdBm);
}
/**
* Constructor.
*
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's)
* @param listener listener in charge of attending events raised by this instance.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final Double initialTransmittedPowerdBm,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(initialTransmittedPowerdBm, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's)
* @param listener listener in charge of attending events raised by this instance.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
final Double initialTransmittedPowerdBm,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(readings, initialTransmittedPowerdBm, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
final Double initialTransmittedPowerdBm) {
super(readings, initialPosition, initialTransmittedPowerdBm);
}
/**
* Constructor.
*
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final Point2D initialPosition, final Double initialTransmittedPowerdBm) {
super(initialPosition, initialTransmittedPowerdBm);
}
/**
* Constructor.
*
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @param listener in charge of attending events raised by this instance.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final Point2D initialPosition, final Double initialTransmittedPowerdBm,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(initialPosition, initialTransmittedPowerdBm, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @param listener listener in charge of attending events raised by this instance.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
final Point2D initialPosition, final Double initialTransmittedPowerdBm,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(readings, initialPosition, initialTransmittedPowerdBm, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @param initialPathLossExponent initial path loss exponent. A typical value is 2.0.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
final Double initialTransmittedPowerdBm, final double initialPathLossExponent) {
super(readings, initialPosition, initialTransmittedPowerdBm, initialPathLossExponent);
}
/**
* Constructor.
*
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @param initialPathLossExponent initial path loss exponent. A typical value is 2.0.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final Point2D initialPosition, final Double initialTransmittedPowerdBm, final double initialPathLossExponent) {
super(initialPosition, initialTransmittedPowerdBm, initialPathLossExponent);
}
/**
* Constructor.
*
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @param initialPathLossExponent initial path loss exponent. A typical value is 2.0.
* @param listener listener in charge of attending events raised by this instance.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final Point2D initialPosition, final Double initialTransmittedPowerdBm,
final double initialPathLossExponent,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(initialPosition, initialTransmittedPowerdBm, initialPathLossExponent, listener);
}
/**
* Constructor.
* Sets signal readings belonging to the same radio source.
*
* @param readings signal readings belonging to the same radio source.
* @param initialPosition initial position to start the estimation of radio
* source position.
* @param initialTransmittedPowerdBm initial transmitted power to start the
* estimation of radio source transmitted power
* (expressed in dBm's).
* @param initialPathLossExponent initial path loss exponent. A typical value is 2.0.
* @param listener listener in charge of attending events raised by this instance.
* @throws IllegalArgumentException if readings are not valid.
*/
public LMedSRobustRangingAndRssiRadioSourceEstimator2D(
final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
final Double initialTransmittedPowerdBm, final double initialPathLossExponent,
final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
super(readings, initialPosition, initialTransmittedPowerdBm, initialPathLossExponent, listener);
}
/**
* Returns threshold to be used to keep the algorithm iterating in case that
* best estimated threshold using median of residuals is not small enough.
* Once a solution is found that generates a threshold below this value, the
* algorithm will stop.
* The stop threshold can be used to prevent the LMedS algorithm to iterate
* too many times in cases where samples have a very similar accuracy.
* For instance, in cases where proportion of outliers is very small (close
* to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
* iterate for a long time trying to find the best solution when indeed
* there is no need to do that if a reasonable threshold has already been
* reached.
* Because of this behaviour the stop threshold can be set to a value much
* lower than the one typically used in RANSAC, and yet the algorithm could
* still produce even smaller thresholds in estimated results.
*
* @return stop threshold to stop the algorithm prematurely when a certain
* accuracy has been reached.
*/
public double getStopThreshold() {
return stopThreshold;
}
/**
* Sets threshold to be used to keep the algorithm iterating in case that
* best estimated threshold using median of residuals is not small enough.
* Once a solution is found that generates a threshold below this value,
* the algorithm will stop.
* The stop threshold can be used to prevent the LMedS algorithm to iterate
* too many times in cases where samples have a very similar accuracy.
* For instance, in cases where proportion of outliers is very small (close
* to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
* iterate for a long time trying to find the best solution when indeed
* there is no need to do that if a reasonable threshold has already been
* reached.
* Because of this behaviour the stop threshold can be set to a value much
* lower than the one typically used in RANSAC, and yet the algorithm could
* still produce even smaller thresholds in estimated results.
*
* @param stopThreshold stop threshold to stop the algorithm prematurely
* when a certain accuracy has been reached.
* @throws IllegalArgumentException if provided value is zero or negative.
* @throws LockedException if this solver is locked.
*/
public void setStopThreshold(final double stopThreshold) throws LockedException {
if (isLocked()) {
throw new LockedException();
}
if (stopThreshold <= MIN_STOP_THRESHOLD) {
throw new IllegalArgumentException();
}
this.stopThreshold = stopThreshold;
}
/**
* Robustly estimates position, transmitted power and path-loss exponent for a
* radio source.
*
* @throws LockedException if instance is busy during estimation.
* @throws NotReadyException if estimator is not ready.
* @throws RobustEstimatorException if estimation fails for any reason
* (i.e. numerical instability, no solution available, etc).
*/
@Override
public void estimate() throws LockedException, NotReadyException, RobustEstimatorException {
if (isLocked()) {
throw new LockedException();
}
if (!isReady()) {
throw new NotReadyException();
}
final var innerEstimator = new LMedSRobustEstimator<>(
new LMedSRobustEstimatorListener<RobustRangingAndRssiRadioSourceEstimator.Solution<Point2D>>() {
@Override
public int getTotalSamples() {
return readings.size();
}
@Override
public int getSubsetSize() {
return Math.max(preliminarySubsetSize, getMinReadings());
}
@Override
public void estimatePreliminarSolutions(
final int[] samplesIndices,
final List<RobustRangingAndRssiRadioSourceEstimator.Solution<Point2D>> solutions) {
solvePreliminarySolutions(samplesIndices, solutions);
}
@Override
public double computeResidual(
final RobustRangingAndRssiRadioSourceEstimator.Solution<Point2D> currentEstimation,
final int i) {
return residual(currentEstimation, i);
}
@Override
public boolean isReady() {
return LMedSRobustRangingAndRssiRadioSourceEstimator2D.this.isReady();
}
@Override
public void onEstimateStart(
final RobustEstimator<RobustRangingAndRssiRadioSourceEstimator
.Solution<Point2D>> estimator) {
// no action needed
}
@Override
public void onEstimateEnd(
final RobustEstimator<RobustRangingAndRssiRadioSourceEstimator
.Solution<Point2D>> estimator) {
// no action needed
}
@Override
public void onEstimateNextIteration(
final RobustEstimator<RobustRangingAndRssiRadioSourceEstimator
.Solution<Point2D>> estimator,
final int iteration) {
if (listener != null) {
listener.onEstimateNextIteration(
LMedSRobustRangingAndRssiRadioSourceEstimator2D.this, iteration);
}
}
@Override
public void onEstimateProgressChange(
final RobustEstimator<RobustRangingAndRssiRadioSourceEstimator
.Solution<Point2D>> estimator,
final float progress) {
if (listener != null) {
listener.onEstimateProgressChange(
LMedSRobustRangingAndRssiRadioSourceEstimator2D.this, progress);
}
}
});
try {
locked = true;
if (listener != null) {
listener.onEstimateStart(this);
}
inliersData = null;
innerEstimator.setConfidence(confidence);
innerEstimator.setMaxIterations(maxIterations);
innerEstimator.setProgressDelta(progressDelta);
final var result = innerEstimator.estimate();
inliersData = innerEstimator.getInliersData();
attemptRefine(result);
if (listener != null) {
listener.onEstimateEnd(this);
}
} catch (final com.irurueta.numerical.LockedException e) {
throw new LockedException(e);
} catch (final com.irurueta.numerical.NotReadyException e) {
throw new NotReadyException(e);
} finally {
locked = false;
}
}
/**
* Returns method being used for robust estimation.
*
* @return method being used for robust estimation.
*/
@Override
public RobustEstimatorMethod getMethod() {
return RobustEstimatorMethod.LMEDS;
}
}