Import Android SDK Platform P [4413397]

/google/data/ro/projects/android/fetch_artifact \
    --bid 4413397 \
    --target sdk_phone_armv7-win_sdk \
    sdk-repo-linux-sources-4413397.zip

AndroidVersion.ApiLevel has been modified to appear as 28

Change-Id: I3cf1f7c36e61c090dcc7de7bcfa812ef2bf96c00

2 files changed, 36 insertions, 20 deletions

diff --git a/android/location/GnssMeasurement.java b/android/location/GnssMeasurement.java
index d24a4774..412cc291 100644
--- a/android/location/GnssMeasurement.java
+++ b/android/location/GnssMeasurement.java
@@ -612,6 +612,16 @@ public final class GnssMeasurement implements Parcelable {
      *
      * <pre>
      *          accumulated delta range = -k * carrier phase    (where k is a constant)</pre>
+     *
+     * <p>Similar to the concept of an RTCM "Phaserange", when the accumulated delta range is
+     * initially chosen, and whenever it is reset, it will retain the integer nature
+     * of the relative carrier phase offset between satellites observed by this receiver, such that
+     * the double difference of this value between receivers and satellites may be used, together
+     * with integer ambiguity resolution, to determine highly precise relative location between
+     * receivers.
+     *
+     * <p>This includes ensuring that all half-cycle ambiguities are resolved before this value is
+     * reported as {@link #ADR_STATE_VALID}.
      */
     public double getAccumulatedDeltaRangeMeters() {
         return mAccumulatedDeltaRangeMeters;
@@ -861,7 +871,7 @@ public final class GnssMeasurement implements Parcelable {
     }
 
     /**
-     * Gets the Signal-to-Noise ratio (SNR) in dB.
+     * Gets the (post-correlation & integration) Signal-to-Noise ratio (SNR) in dB.
      *
      * <p>The value is only available if {@link #hasSnrInDb()} is {@code true}.
      */
diff --git a/android/location/Location.java b/android/location/Location.java
index e8eaa59a..e7f903e8 100644
--- a/android/location/Location.java
+++ b/android/location/Location.java
@@ -813,15 +813,16 @@ public class Location implements Parcelable {
     /**
      * Get the estimated vertical accuracy of this location, in meters.
      *
-     * <p>We define vertical accuracy as the radius of 68% confidence. In other
-     * words, if you draw a circle centered at this location's altitude, and with a radius
-     * equal to the vertical accuracy, then there is a 68% probability that the true altitude is
-     * inside the circle.
+     * <p>We define vertical accuracy at 68% confidence.  Specifically, as 1-side of the
+     * 2-sided range above and below the estimated altitude reported by {@link #getAltitude()},
+     * within which there is a 68% probability of finding the true altitude.
      *
-     * <p>In statistical terms, it is assumed that location errors
-     * are random with a normal distribution, so the 68% confidence circle
-     * represents one standard deviation. Note that in practice, location
-     * errors do not always follow such a simple distribution.
+     * <p>In the case where the underlying distribution is assumed Gaussian normal, this would be
+     * considered 1 standard deviation.
+     *
+     * <p>For example, if {@link #getAltitude()} returns 150, and
+     * {@link #getVerticalAccuracyMeters()} ()} returns 20 then there is a 68% probability
+     * of the true altitude being between 130 and 170 meters.
      *
      * <p>If this location does not have a vertical accuracy, then 0.0 is returned.
      */
@@ -866,14 +867,16 @@ public class Location implements Parcelable {
     /**
      * Get the estimated speed accuracy of this location, in meters per second.
      *
-     * <p>We define speed accuracy as a 1-standard-deviation value, i.e. as 1-side of the
-     * 2-sided range above and below the estimated
-     * speed reported by {@link #getSpeed()}, within which there is a 68% probability of
-     * finding the true speed.
+     * <p>We define speed accuracy at 68% confidence.  Specifically, as 1-side of the
+     * 2-sided range above and below the estimated speed reported by {@link #getSpeed()},
+     * within which there is a 68% probability of finding the true speed.
+     *
+     * <p>In the case where the underlying
+     * distribution is assumed Gaussian normal, this would be considered 1 standard deviation.
      *
-     * <p>For example, if {@link #getSpeed()} returns 5.0, and
-     * {@link #getSpeedAccuracyMetersPerSecond()} returns 1.0, then there is a 68% probably of the
-     * true speed being between 4.0 and 6.0 meters per second.
+     * <p>For example, if {@link #getSpeed()} returns 5, and
+     * {@link #getSpeedAccuracyMetersPerSecond()} returns 1, then there is a 68% probability of
+     * the true speed being between 4 and 6 meters per second.
      *
      * <p>Note that the speed and speed accuracy is often better than would be obtained simply from
      * differencing sequential positions, such as when the Doppler measurements from GNSS satellites
@@ -922,13 +925,16 @@ public class Location implements Parcelable {
     /**
      * Get the estimated bearing accuracy of this location, in degrees.
      *
-     * <p>We define bearing accuracy as a 1-standard-deviation value, i.e. as 1-side of the
+     * <p>We define bearing accuracy at 68% confidence.  Specifically, as 1-side of the
      * 2-sided range on each side of the estimated bearing reported by {@link #getBearing()},
      * within which there is a 68% probability of finding the true bearing.
      *
-     * <p>For example, if {@link #getBearing()} returns 60., and
-     * {@link #getBearingAccuracyDegrees()} ()} returns 10., then there is a 68% probably of the
-     * true bearing being between 50. and 70. degrees.
+     * <p>In the case where the underlying distribution is assumed Gaussian normal, this would be
+     * considered 1 standard deviation.
+     *
+     * <p>For example, if {@link #getBearing()} returns 60, and
+     * {@link #getBearingAccuracyDegrees()} ()} returns 10, then there is a 68% probability of the
+     * true bearing being between 50 and 70 degrees.
      *
      * <p>If this location does not have a bearing accuracy, then 0.0 is returned.
      */