diff --git a/include/gnss_utils/gnss_utils.h b/include/gnss_utils/gnss_utils.h
index 0102a6c72bdafe08efeb4e3ae61e9d112221948c..0efa94f55c532ee42ff3560cb8ab4f101389c1b9 100644
--- a/include/gnss_utils/gnss_utils.h
+++ b/include/gnss_utils/gnss_utils.h
@@ -35,7 +35,7 @@ struct ComputePosOutput
   Eigen::Vector3d vel;        // velocity (m/s)
   Eigen::Matrix3d pos_covar;  // position covariance (m^2)
                               // {c_xx,c_yy,c_zz,c_xy,c_yz,c_zx}
-  Eigen::VectorXd rcv_bias;   // receiver clock bias to time systems (s)
+  Eigen::VectorXd rcv_bias;   // receiver clock bias to time systems (s) 0: receiver clock bias (s), 1: glo-gps time offset (s), 2: gal-gps time offset (s), 3: bds-gps time offset (s)
   int             type;       // coordinates used (0:xyz-ecef,1:enu-baseline)
   int             stat;       // solution status (SOLQ_???)
   int             ns;         // number of valid satellites