diff --git a/libraries/SITL/picojson.h b/libraries/SITL/picojson.h
index bab8aa7fb5..b7a3c36e03 100644
--- a/libraries/SITL/picojson.h
+++ b/libraries/SITL/picojson.h
@@ -225,8 +225,8 @@ public:
 private:
   template <typename T> value(const T *); // intentionally defined to block implicit conversion of pointer to bool
   template <typename Iter> static void _indent(Iter os, int indent);
-  template <typename Iter> void _serialize(Iter os, int indent) const;
-  std::string _serialize(int indent) const;
+  template <typename Iter> void _Serialize(Iter os, int indent) const;
+  std::string _Serialize(int indent) const;
   void clear();
 };
 
@@ -590,11 +590,11 @@ template <typename Iter> void serialize_str(const std::string &s, Iter oi) {
 }
 
 template <typename Iter> void value::serialize(Iter oi, bool prettify) const {
-  return _serialize(oi, prettify ? 0 : -1);
+  return _Serialize(oi, prettify ? 0 : -1);
 }
 
 inline std::string value::serialize(bool prettify) const {
-  return _serialize(prettify ? 0 : -1);
+  return _Serialize(prettify ? 0 : -1);
 }
 
 template <typename Iter> void value::_indent(Iter oi, int indent) {
@@ -604,7 +604,7 @@ template <typename Iter> void value::_indent(Iter oi, int indent) {
   }
 }
 
-template <typename Iter> void value::_serialize(Iter oi, int indent) const {
+template <typename Iter> void value::_Serialize(Iter oi, int indent) const {
   switch (type_) {
   case string_type:
     serialize_str(*u_.string_, oi);
@@ -621,7 +621,7 @@ template <typename Iter> void value::_serialize(Iter oi, int indent) const {
       if (indent != -1) {
         _indent(oi, indent);
       }
-      i->_serialize(oi, indent);
+      i->_Serialize(oi, indent);
     }
     if (indent != -1) {
       --indent;
@@ -649,7 +649,7 @@ template <typename Iter> void value::_serialize(Iter oi, int indent) const {
       if (indent != -1) {
         *oi++ = ' ';
       }
-      i->second._serialize(oi, indent);
+      i->second._Serialize(oi, indent);
     }
     if (indent != -1) {
       --indent;
@@ -669,9 +669,9 @@ template <typename Iter> void value::_serialize(Iter oi, int indent) const {
   }
 }
 
-inline std::string value::_serialize(int indent) const {
+inline std::string value::_Serialize(int indent) const {
   std::string s;
-  _serialize(std::back_inserter(s), indent);
+  _Serialize(std::back_inserter(s), indent);
   return s;
 }