Clarify C/No reflects the tracked portion of a GnssMeasurement

Test: Comment updates only. Verified it builds.
Bug: 117942478
Change-Id: Ia069fbdb396b5bfc76d3dbeabd0c54622f568ade
Fixes: 117942478
diff --git a/current.txt b/current.txt
index b1a651f..b34bf8c 100644
--- a/current.txt
+++ b/current.txt
@@ -386,7 +386,7 @@
 
 # ABI preserving changes to HALs during Android Q
 da33234403ff5d60f3473711917b9948e6484a4260b5247acdafb111193a9de2 android.hardware.configstore@1.0::ISurfaceFlingerConfigs
-78886339f2c848cf13c1edd3ebba63f89796b2620d3bf3b5c21d038a53519ba0 android.hardware.gnss@1.0::IGnssMeasurementCallback
+d702fb01dc2a0733aa820b7eb65435ee3334f75632ef880bafd2fb8803a20a58 android.hardware.gnss@1.0::IGnssMeasurementCallback
 b7ecf29927055ec422ec44bf776223f07d79ad9f92ccf9becf167e62c2607e7a android.hardware.keymaster@4.0::IKeymasterDevice
 574e8f1499436fb4075894dcae0b36682427956ecb114f17f1fe22d116a83c6b android.hardware.neuralnetworks@1.0::IPreparedModel
 1fb32361286b938d48a55c2539c846732afce0b99fe08590f556643125bc13d3 android.hardware.neuralnetworks@1.0::types
diff --git a/gnss/1.0/IGnssMeasurementCallback.hal b/gnss/1.0/IGnssMeasurementCallback.hal
index d3489e6..2d44766 100644
--- a/gnss/1.0/IGnssMeasurementCallback.hal
+++ b/gnss/1.0/IGnssMeasurementCallback.hal
@@ -436,6 +436,10 @@
          * Carrier-to-noise density in dB-Hz, typically in the range [0, 63].
          * It contains the measured C/N0 value for the signal at the antenna port.
          *
+         * If a signal has separate components (e.g. Pilot and Data channels) and
+         * the receiver only processes one of the components, then the reported
+         * cN0DbHz reflects only the component that is processed.
+         *
          * This value is mandatory.
          */
         double cN0DbHz;