diff --git a/current.txt b/current.txt
index ac65326..bdbe1b8 100644
--- a/current.txt
+++ b/current.txt
@@ -771,6 +771,7 @@
 c2f64133b83ede65c9939ef97ab5bd867b73faf3dba0e7e69f77c3c43d9e487e android.hardware.contexthub@1.0::IContexthubCallback
 bda492ec4021d13869de72bd6f8c15c5837b78d6136b8d538efec5320573a5ec android.hardware.gnss@1.0::IGnssMeasurementCallback
 6a271e493907e8ba20912e42771bd0d99ae45431a851d5675ef9496d02510a34 android.hardware.gnss@1.1::IGnssMeasurementCallback
+11e9e1a1fd0c9b3d9648750d4b10dc2a839d3a6688904c3fc49500a4e7ca75b0 android.hardware.gnss@2.1::IGnssMeasurementCallback
 2c331a9605f3a08d9c1e0a36169ca57758bc43c11a78ef3f3730509885e52c15 android.hardware.graphics.composer@2.4::IComposerClient
 3da3ce039247872d95c6bd48621dbfdfa1c2d2a91a90f257862f87ee2bc46300 android.hardware.health@2.1::types
 9679f27a42f75781c8993ef163ed92808a1928de186639834841d0b8e326e63d android.hardware.gatekeeper@1.0::IGatekeeper
diff --git a/gnss/2.1/IGnssMeasurementCallback.hal b/gnss/2.1/IGnssMeasurementCallback.hal
index 60a5423..beef4fd 100644
--- a/gnss/2.1/IGnssMeasurementCallback.hal
+++ b/gnss/2.1/IGnssMeasurementCallback.hal
@@ -103,6 +103,9 @@
          *
          * The value does not include the inter-frequency Ionospheric bias.
          *
+         * The sign of the value is defined by the following equation:
+         *      corrected pseudorange = raw pseudorange - fullInterSignalBias
+         *
          * The full ISB of GnssClock.referenceSignalTypeForIsb is defined to be 0.0 nanoseconds.
          */
         double fullInterSignalBiasNs;
@@ -127,6 +130,9 @@
          * - Satellite inter-code bias (e.g., Differential Code Bias (DCB)) (with respect to the
          *   code type in GnssClock.referenceSignalTypeForIsb)
          *
+         * The sign of the value is defined by the following equation:
+         *      corrected pseudorange = raw pseudorange - satelliteInterSignalBias
+         *
          * The satellite ISB of GnssClock.referenceSignalTypeForIsb is defined to be 0.0
          * nanoseconds.
          */