Posted by Geoffrey Boullanger – Senior Software program Engineer, Shandor Dektor – Sensors Algorithms Engineer, Martin Frassl and Benjamin Joseph – Technical Leads and Managers
Machine orientation, or perspective, is used as an enter sign for a lot of use circumstances: digital or augmented actuality, gesture detection, or compass and navigation – any time the app wants the orientation of a tool in relation to its environment. We’ve heard from builders that orientation is difficult to get proper, with frequent consumer complaints when orientation is inaccurate. A maps app ought to present the proper course to stroll in the direction of when a consumer is navigating to an thrilling restaurant in a international metropolis!
The Fused Orientation Supplier (FOP) is a brand new API in Google Play providers that gives high quality and constant machine orientation by fusing indicators from accelerometer, gyroscope and magnetometer.
Though presently the Android Rotation Vector already offers machine orientation (and can proceed to take action), the brand new FOP offers extra constant conduct and excessive efficiency throughout units. We designed the FOP API to be much like the Rotation Vector to make the transition as straightforward as attainable for builders.
Specifically, the Fused Orientation Supplier
- Gives a unified implementation throughout units: an API in Google Play providers signifies that there is no such thing as a implementation variance throughout completely different producers. Algorithm updates may be rolled out shortly and unbiased of Android platform updates;
- Straight incorporates native magnetic declination, if out there;
- Compensates for decrease high quality sensors and OEM implementations (e.g., gyro bias, sensor timing).
In sure circumstances, the FOP returns values piped by from the AOSP Rotation Vector, tailored to include magnetic declination.
How one can use the FOP API
Machine orientation updates may be requested by creating and sending a DeviceOrientationRequest object, which defines some specifics of the request just like the replace interval.
The FOP then outputs a stream of the machine’s orientation estimates as quaternions. The orientation is referenced to geographic north. In circumstances the place the native magnetic declination is just not recognized (e.g., location is just not out there), the orientation shall be relative to magnetic north.
As well as, the FOP offers the machine’s heading and accuracy, that are derived from the orientation estimate. This is similar heading that’s proven in Google Maps, which makes use of the FOP as effectively. We lately added adjustments to raised deal with magnetic disturbances, to enhance the reliability of the cone for Google Maps and FOP purchasers.
The replace price may be set by requesting a selected replace interval. The FOP doesn’t assure a minimal or most replace price. For instance, the replace price may be sooner than requested if one other app has a sooner parallel request, or it may be slower as requested if the machine doesn’t assist the excessive price.
For full specification of the API, please seek the advice of the API documentation:
Instance utilization (Kotlin)
bundle ...
import android.content material.Context
import com.google.android.gms.location.DeviceOrientation
import com.google.android.gms.location.DeviceOrientationListener
import com.google.android.gms.location.DeviceOrientationRequest
import com.google.android.gms.location.FusedOrientationProviderClient
import com.google.android.gms.location.LocationServices
import com.google.widespread.flogger.FluentLogger
import java.util.concurrent.Executors
class Instance(context: Context) {
non-public val logger: FluentLogger = FluentLogger.forEnclosingClass()
// Get the FOP API shopper
non-public val fusedOrientationProviderClient: FusedOrientationProviderClient =
LocationServices.getFusedOrientationProviderClient(context)
// Create an FOP listener
non-public val listener: DeviceOrientationListener =
DeviceOrientationListener { orientation: DeviceOrientation ->
// Use the orientation object returned by the FOP, e.g.
logger.atFinest().log("Machine Orientation: %s deg", orientation.headingDegrees)
}
enjoyable begin() {
// Create an FOP request
val request =
DeviceOrientationRequest.Builder(DeviceOrientationRequest.OUTPUT_PERIOD_DEFAULT).construct()
// Create (or re-use) an Executor or Looper, e.g.
val executor = Executors.newSingleThreadExecutor()
// Register the request and listener
fusedOrientationProviderClient
.requestOrientationUpdates(request, executor, listener)
.addOnSuccessListener { logger.atInfo().log("FOP: Registration Success") }
.addOnFailureListener { e: Exception? ->
logger.atSevere().withCause(e).log("FOP: Registration Failure")
}
}
enjoyable cease() {
// Unregister the listener
fusedOrientationProviderClient.removeOrientationUpdates(listener)
}
}
Technical background
The Android ecosystem has all kinds of system implementations for sensors. Gadgets ought to meet the standards within the Android compatibility definition doc (CDD) and should have an accelerometer, gyroscope, and magnetometer out there to make use of the fused orientation supplier. It’s preferable that the machine vendor implements the excessive constancy sensor portion of the CDD.
Although Android units adhere to the Android CDD, beneficial sensor specs usually are not tight sufficient to completely forestall orientation inaccuracies. Examples of this embrace magnetometer interference from inner sources, and delayed, inaccurate or nonuniform sensor sampling. Moreover, the setting across the machine often contains supplies that distort the geomagnetic area, and consumer conduct can differ extensively. To cope with this, the FOP performs quite a few duties with a view to present a strong and correct orientation:
- Synchronize sensors operating on completely different clocks and delays;
- Compensate for the laborious iron offset (magnetometer bias);
- Fuse accelerometer, gyroscope, and magnetometer measurements to find out the orientation of the machine on the planet;
- Compensate for gyro drift (gyro bias) whereas transferring;
- Produce a practical estimate of the compass heading accuracy.
Now we have validated our algorithms on complete check knowledge to supply a top quality consequence on all kinds of units.
Availability and limitations
The Fused Orientation Supplier is on the market on all units operating Google Play providers on Android 5 (Lollipop) and above. Builders want so as to add the dependency play-services-location:21.2.0 (or above) to entry the brand new API.
Permissions
No permissions are required to make use of the FOP API. The output price is restricted to 200Hz on units operating API stage 31 (Android S) or larger, until the android.permissions.HIGH_SAMPLING_RATE_SENSORS permission was added to your Manifest.xml.
Energy consideration
At all times request the longest replace interval (lowest frequency) that’s adequate to your use case. Whereas extra frequent FOP updates may be required for top precision duties (for instance Augmented Actuality), it comes with an influence price. In the event you have no idea which replace interval to make use of, we suggest beginning with DeviceOrientationRequest::OUTPUT_PERIOD_DEFAULT because it suits most shopper wants.
Foreground conduct
FOP updates are solely out there to apps operating within the foreground.
Copyright 2023 Google LLC. SPDX-License-Identifier: Apache-2.0
Leave a Comment