diff --git a/protobuf_definitions/message_formats.proto b/protobuf_definitions/message_formats.proto
index 74f45c1a..49953055 100644
--- a/protobuf_definitions/message_formats.proto
+++ b/protobuf_definitions/message_formats.proto
@@ -406,6 +406,7 @@ message PositionEstimate {
   float speed_over_ground = 12; // Speed over ground (m/s).
   float course_over_ground = 13; // Course over ground (°).
   int32 time_since_reset_sec = 14; // Time since reset (s).
+  float accuracy = 15; // Accuracy of the position estimate (m).
 }
 
 // Heading source used during reset of the position estimate.