diff --git a/c/include/libsbp/legacy/navigation.h b/c/include/libsbp/legacy/navigation.h
index 1bd7e72e6b..0dc638a354 100644
--- a/c/include/libsbp/legacy/navigation.h
+++ b/c/include/libsbp/legacy/navigation.h
@@ -951,7 +951,7 @@ typedef struct SBP_ATTR_PACKED {
   u8 sin;       /**< System Identification Number. */
   u16 utn;      /**< Utilized Transformation Message. */
   u16 re_t0;    /**< Reference Epoch t0 for transformation parameter
-                     set given as Modified Julian Day (MDJ) Number
+                     set given as Modified Julian Day (MJD) Number
                      minus 44244 days. [1 day] */
   s32 delta_X0; /**< Translation in X for Reference Epoch t0. [0.001 m] */
   s32 delta_Y0; /**< Translation in Y for Reference Epoch t0. [0.001 m] */
diff --git a/c/include/libsbp/v4/navigation/MSG_REFERENCE_FRAME_PARAM.h b/c/include/libsbp/v4/navigation/MSG_REFERENCE_FRAME_PARAM.h
index e92f9fe49b..b3b32732d5 100644
--- a/c/include/libsbp/v4/navigation/MSG_REFERENCE_FRAME_PARAM.h
+++ b/c/include/libsbp/v4/navigation/MSG_REFERENCE_FRAME_PARAM.h
@@ -66,7 +66,7 @@ typedef struct {
 
   /**
    * Reference Epoch t0 for transformation parameter set given as Modified
-   * Julian Day (MDJ) Number minus 44244 days. [1 day]
+   * Julian Day (MJD) Number minus 44244 days. [1 day]
    */
   u16 re_t0;
 
diff --git a/docs/sbp.pdf b/docs/sbp.pdf
index fa5b2d6e6b..70dd93d240 100644
Binary files a/docs/sbp.pdf and b/docs/sbp.pdf differ
diff --git a/haskell/src/SwiftNav/SBP/Navigation.hs b/haskell/src/SwiftNav/SBP/Navigation.hs
index 4e9f2a4313..0b0088c0d1 100644
--- a/haskell/src/SwiftNav/SBP/Navigation.hs
+++ b/haskell/src/SwiftNav/SBP/Navigation.hs
@@ -2379,7 +2379,7 @@ data MsgReferenceFrameParam = MsgReferenceFrameParam
     -- ^ Utilized Transformation Message.
   , _msgReferenceFrameParam_re_t0      :: !Word16
     -- ^ Reference Epoch t0 for transformation parameter set given as Modified
-    -- Julian Day (MDJ) Number minus 44244 days.
+    -- Julian Day (MJD) Number minus 44244 days.
   , _msgReferenceFrameParam_delta_X0   :: !Int32
     -- ^ Translation in X for Reference Epoch t0.
   , _msgReferenceFrameParam_delta_Y0   :: !Int32
diff --git a/java/src/com/swiftnav/sbp/navigation/MsgReferenceFrameParam.java b/java/src/com/swiftnav/sbp/navigation/MsgReferenceFrameParam.java
index 52bf3143cb..4f88c6f4b3 100644
--- a/java/src/com/swiftnav/sbp/navigation/MsgReferenceFrameParam.java
+++ b/java/src/com/swiftnav/sbp/navigation/MsgReferenceFrameParam.java
@@ -37,7 +37,7 @@ public class MsgReferenceFrameParam extends SBPMessage {
     public int utn;
 
     /**
-     * Reference Epoch t0 for transformation parameter set given as Modified Julian Day (MDJ) Number
+     * Reference Epoch t0 for transformation parameter set given as Modified Julian Day (MJD) Number
      * minus 44244 days.
      */
     public int re_t0;
diff --git a/javascript/sbp/navigation.js b/javascript/sbp/navigation.js
index 637c808215..6cef041f93 100644
--- a/javascript/sbp/navigation.js
+++ b/javascript/sbp/navigation.js
@@ -2196,7 +2196,7 @@ MsgUtcLeapSecond.prototype.fieldSpec.push(['count_after', 'writeInt8', 1]);
  * @field sin number (unsigned 8-bit int, 1 byte) System Identification Number.
  * @field utn number (unsigned 16-bit int, 2 bytes) Utilized Transformation Message.
  * @field re_t0 number (unsigned 16-bit int, 2 bytes) Reference Epoch t0 for transformation parameter set given as Modified Julian Day
- *   (MDJ) Number minus 44244 days.
+ *   (MJD) Number minus 44244 days.
  * @field delta_X0 number (signed 32-bit int, 4 bytes) Translation in X for Reference Epoch t0.
  * @field delta_Y0 number (signed 32-bit int, 4 bytes) Translation in Y for Reference Epoch t0.
  * @field delta_Z0 number (signed 32-bit int, 4 bytes) Translation in Z for Reference Epoch t0.
diff --git a/python/sbp/navigation.py b/python/sbp/navigation.py
index 1ccdb9d276..2516028505 100755
--- a/python/sbp/navigation.py
+++ b/python/sbp/navigation.py
@@ -5264,7 +5264,7 @@ class MsgReferenceFrameParam(SBP):
     Utilized Transformation Message.
   re_t0 : int
     Reference Epoch t0 for transformation parameter set given as Modified
-    Julian Day (MDJ) Number minus 44244 days.
+    Julian Day (MJD) Number minus 44244 days.
   delta_X0 : int
     Translation in X for Reference Epoch t0.
   delta_Y0 : int
diff --git a/rust/sbp/src/messages/navigation.rs b/rust/sbp/src/messages/navigation.rs
index f260c74d9c..0093d3dc5d 100644
--- a/rust/sbp/src/messages/navigation.rs
+++ b/rust/sbp/src/messages/navigation.rs
@@ -6022,7 +6022,7 @@ pub mod msg_reference_frame_param {
         #[cfg_attr(feature = "serde", serde(rename(serialize = "utn")))]
         pub utn: u16,
         /// Reference Epoch t0 for transformation parameter set given as Modified
-        /// Julian Day (MDJ) Number minus 44244 days.
+        /// Julian Day (MJD) Number minus 44244 days.
         #[cfg_attr(feature = "serde", serde(rename(serialize = "re_t0")))]
         pub re_t0: u16,
         /// Translation in X for Reference Epoch t0.
diff --git a/spec/yaml/swiftnav/sbp/navigation.yaml b/spec/yaml/swiftnav/sbp/navigation.yaml
index db9e74ed36..06a970daf1 100644
--- a/spec/yaml/swiftnav/sbp/navigation.yaml
+++ b/spec/yaml/swiftnav/sbp/navigation.yaml
@@ -2507,7 +2507,7 @@ definitions:
            units: 1 day
            desc: >
              Reference Epoch t0 for transformation parameter set given as
-             Modified Julian Day (MDJ) Number minus 44244 days.
+             Modified Julian Day (MJD) Number minus 44244 days.
        - delta_X0:
            type: s32
            units: 0.001 m