diff --git a/gtsam_unstable/slam/AHRS.cpp b/gtsam_unstable/slam/AHRS.cpp
index bee6bcef6..cbd1096a9 100644
--- a/gtsam_unstable/slam/AHRS.cpp
+++ b/gtsam_unstable/slam/AHRS.cpp
@@ -80,10 +80,10 @@ std::pair<Mechanization_bRn2, KalmanFilter::State> AHRS::initialize(double g_e)
   double g3 = b_g(2);
   double g23 = g2 * g2 + g3 * g3;
   double g123 = g1 * g1 + g23;
-  double f = 1 / (sqrt(g23) * g123);
+  double f = 1 / (std::sqrt(g23) * g123);
   Matrix H_g = Matrix_(3, 3,
       0.0, g3 / g23, -(g2 / g23),                       // roll
-      sqrt(g23) / g123, -f * (g1 * g2), -f * (g1 * g3), // pitch
+      std::sqrt(g23) / g123, -f * (g1 * g2), -f * (g1 * g3), // pitch
       0.0, 0.0, 0.0);                                   // we don't know anything on yaw
 
   // Calculate the initial covariance matrix for the error state dx, Farrell08book eq. 10.66
diff --git a/gtsam_unstable/slam/AHRS.h b/gtsam_unstable/slam/AHRS.h
index 89f8b2b5e..284fe2fc6 100644
--- a/gtsam_unstable/slam/AHRS.h
+++ b/gtsam_unstable/slam/AHRS.h
@@ -9,13 +9,14 @@
 #define AHRS_H_
 
 #include "Mechanization_bRn2.h"
+#include <gtsam_unstable/base/dllexport.h>
 #include <gtsam/linear/KalmanFilter.h>
 
 namespace gtsam {
 
 Matrix cov(const Matrix& m);
 
-class AHRS {
+class GTSAM_UNSTABLE_EXPORT AHRS {
 
 private:
 
diff --git a/gtsam_unstable/slam/Mechanization_bRn2.h b/gtsam_unstable/slam/Mechanization_bRn2.h
index 0a71da06d..b81e685d4 100644
--- a/gtsam_unstable/slam/Mechanization_bRn2.h
+++ b/gtsam_unstable/slam/Mechanization_bRn2.h
@@ -9,11 +9,12 @@
 
 #include <gtsam/geometry/Rot3.h>
 #include <gtsam/base/Vector.h>
+#include <gtsam_unstable/base/dllexport.h>
 #include <list>
 
 namespace gtsam {
 
-class Mechanization_bRn2 {
+class GTSAM_UNSTABLE_EXPORT Mechanization_bRn2 {
 
 private:
   Rot3 bRn_;  ///<   rotation from nav to body