diff --git a/.gitmodules b/.gitmodules
index c869803b7a..6a4f815d42 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -16,3 +16,6 @@
 [submodule "unittests/gtest"]
 	path = unittests/gtest
 	url = https://github.com/sjwilks/gtest.git
+[submodule "src/lib/eigen"]
+	path = src/lib/eigen
+	url = https://github.com/PX4/eigen.git
diff --git a/src/lib/eigen b/src/lib/eigen
new file mode 160000
index 0000000000..e7850ed81f
--- /dev/null
+++ b/src/lib/eigen
@@ -0,0 +1 @@
+Subproject commit e7850ed81f9c469e02df496ef09ae32ec0379b71