src.android.location.CorrelationVector Maven / Gradle / Ivy
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/*
* Copyright (C) 2020 The Android Open Source Project
*
* 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 android.location;
import android.annotation.FloatRange;
import android.annotation.NonNull;
import android.annotation.SystemApi;
import android.os.Parcel;
import android.os.Parcelable;
import com.android.internal.util.Preconditions;
import java.util.Arrays;
import java.util.Objects;
/**
* Contains info about the correlation output of incoming GNSS signal and a local copy of
* its corresponding spreading code at a given frequency offset.
*
* @hide
*/
@SystemApi
public final class CorrelationVector implements Parcelable {
private final double mSamplingWidthMeters;
private final double mSamplingStartMeters;
private final double mFrequencyOffsetMetersPerSecond;
@NonNull private final int[] mMagnitude;
/**
* Returns the space between correlation samples in meters.
*/
@FloatRange(from = 0.0f, fromInclusive = false)
public double getSamplingWidthMeters() {
return mSamplingWidthMeters;
}
/**
* Returns the offset of the first sampling bin in meters.
*
* The following sampling bins are located at positive offsets from this value as follows:
* samplingStartMeters, samplingStartMeters + samplingWidthMeters, ... , samplingStartMeters +
* (magnitude.size-1) * samplingWidthMeters.
*
*/
@FloatRange(from = 0.0f)
public double getSamplingStartMeters() {
return mSamplingStartMeters;
}
/**
* Returns the frequency offset from reported pseudorange rate for this CorrelationVector.
*/
@FloatRange(from = 0.0f)
public double getFrequencyOffsetMetersPerSecond() {
return mFrequencyOffsetMetersPerSecond;
}
/**
* Returns the data array representing normalized correlation magnitude values.
*
*
The data are normalized correlation magnitude values from -1 to 1, the reported value must
* be encoded as signed 16 bit integer where 1 is represented by 32767 and -1 is represented
* by -32768.
*
*
The values are quantized using a 16bit integer to save on the data size since the array
* contains real data and it might grow.
*
*/
@NonNull
public int[] getMagnitude() {
return mMagnitude.clone();
}
private CorrelationVector(Builder builder) {
Preconditions.checkNotNull(builder.mMagnitude, "Magnitude array must not be null");
Preconditions.checkArgumentPositive(builder.mMagnitude.length,
"Magnitude array must have non-zero length");
Preconditions.checkArgument(builder.mFrequencyOffsetMetersPerSecond >= 0.0,
"FrequencyOffsetMetersPerSecond must be non-negative (greater than or equal to 0)");
Preconditions.checkArgument(builder.mSamplingWidthMeters > 0.0,
"SamplingWidthMeters must be positive (greater than 0)");
mMagnitude = builder.mMagnitude;
mFrequencyOffsetMetersPerSecond = builder.mFrequencyOffsetMetersPerSecond;
mSamplingWidthMeters = builder.mSamplingWidthMeters;
mSamplingStartMeters = builder.mSamplingStartMeters;
}
private CorrelationVector(Parcel in) {
mSamplingWidthMeters = in.readDouble();
mSamplingStartMeters = in.readDouble();
mFrequencyOffsetMetersPerSecond = in.readDouble();
mMagnitude = new int[in.readInt()];
in.readIntArray(mMagnitude);
}
/*
* Method definitions to support Parcelable operations.
*/
public static final @NonNull Parcelable.Creator CREATOR =
new Parcelable.Creator() {
@Override
public CorrelationVector createFromParcel(Parcel parcel) {
return new CorrelationVector(parcel);
}
@Override
public CorrelationVector[] newArray(int size) {
return new CorrelationVector[size];
}
};
@Override
public int describeContents() {
return 0;
}
@NonNull
@Override
public String toString() {
return "CorrelationVector{"
+ "FrequencyOffsetMetersPerSecond=" + mFrequencyOffsetMetersPerSecond
+ ", SamplingWidthMeters=" + mSamplingWidthMeters
+ ", SamplingStartMeters=" + mSamplingStartMeters
+ ", Magnitude=" + Arrays.toString(mMagnitude)
+ '}';
}
@Override
public void writeToParcel(@NonNull Parcel dest, int flags) {
dest.writeDouble(mSamplingWidthMeters);
dest.writeDouble(mSamplingStartMeters);
dest.writeDouble(mFrequencyOffsetMetersPerSecond);
dest.writeInt(mMagnitude.length);
dest.writeIntArray(mMagnitude);
}
/**
* Returns true if this {@link CorrelationVector} is equivalent to the given object.
* Returns false otherwise.
*/
@Override
public boolean equals(Object object) {
if (object == this) {
return true;
}
if (!(object instanceof CorrelationVector)) {
return false;
}
CorrelationVector c = (CorrelationVector) object;
return Arrays.equals(mMagnitude, c.getMagnitude())
&& Double.compare(mSamplingWidthMeters, c.getSamplingWidthMeters()) == 0
&& Double.compare(mSamplingStartMeters, c.getSamplingStartMeters()) == 0
&& Double.compare(mFrequencyOffsetMetersPerSecond,
c.getFrequencyOffsetMetersPerSecond()) == 0;
}
@Override
public int hashCode() {
return Objects.hash(mSamplingWidthMeters, mSamplingStartMeters,
mFrequencyOffsetMetersPerSecond, Arrays.hashCode(mMagnitude));
}
/**
* Builder class for CorrelationVector.
*/
public static final class Builder {
private double mSamplingWidthMeters;
private double mSamplingStartMeters;
private double mFrequencyOffsetMetersPerSecond;
@NonNull private int[] mMagnitude;
/** Sets the space between correlation samples in meters. */
@NonNull
public Builder setSamplingWidthMeters(
@FloatRange(from = 0.0f, fromInclusive = false) double samplingWidthMeters) {
mSamplingWidthMeters = samplingWidthMeters;
return this;
}
/** Sets the offset of the first sampling bin in meters. */
@NonNull
public Builder setSamplingStartMeters(@FloatRange(from = 0.0f) double samplingStartMeters) {
mSamplingStartMeters = samplingStartMeters;
return this;
}
/** Sets the frequency offset from reported pseudorange rate for this CorrelationVector */
@NonNull
public Builder setFrequencyOffsetMetersPerSecond(
@FloatRange(from = 0.0f) double frequencyOffsetMetersPerSecond) {
mFrequencyOffsetMetersPerSecond = frequencyOffsetMetersPerSecond;
return this;
}
/** Sets the data array representing normalized correlation magnitude values. */
@NonNull
public Builder setMagnitude(@NonNull int[] magnitude) {
mMagnitude = magnitude;
return this;
}
/**
* Build CorrelationVector object.
*
* @return instance of CorrelationVector
*/
@NonNull
public CorrelationVector build() {
return new CorrelationVector(this);
}
}
}