diff --git a/location/java/android/location/GnssMeasurement.java b/location/java/android/location/GnssMeasurement.java index 4cd3616566c2f..ecdd4b616e0fd 100644 --- a/location/java/android/location/GnssMeasurement.java +++ b/location/java/android/location/GnssMeasurement.java @@ -214,6 +214,25 @@ public final class GnssMeasurement implements Parcelable { * *
When this bit is unset, the {@link #getAccumulatedDeltaRangeMeters()} corresponds to the * carrier phase measurement plus an accumulated integer number of carrier half cycles. + * + *
For signals that have databits, the carrier phase tracking loops typically use a costas + * loop discriminator. This type of tracking loop introduces a half-cycle ambiguity that is + * resolved by searching through the received data for known patterns of databits (e.g. GPS uses + * the TLM word) which then determines the polarity of the incoming data and resolves the + * half-cycle ambiguity. + * + *
Before the half-cycle ambiguity has been resolved it is possible that the ADR_STATE_VALID + * flag is set: + * + *
This includes ensuring that all half-cycle ambiguities are resolved before this value is - * reported as {@link #ADR_STATE_VALID}. - * *
The alignment of the phase measurement will not be adjusted by the receiver so the * in-phase and quadrature phase components will have a quarter cycle offset as they do when * transmitted from the satellites. If the measurement is from a combination of the in-phase