diff --git a/libraries/AP_Logger/LogStructure.h b/libraries/AP_Logger/LogStructure.h
index 54de203309..466e85a517 100644
--- a/libraries/AP_Logger/LogStructure.h
+++ b/libraries/AP_Logger/LogStructure.h
@@ -1,69 +1,28 @@
 #pragma once
 
 /*
-  unfortunately these need to be macros because of a limitation of
-  named member structure initialisation in g++
- */
-#define LOG_PACKET_HEADER	       uint8_t head1, head2, msgid;
-#define LOG_PACKET_HEADER_INIT(id) head1 : HEAD_BYTE1, head2 : HEAD_BYTE2, msgid : id
-#define LOG_PACKET_HEADER_LEN 3 // bytes required for LOG_PACKET_HEADER
-
-// once the logging code is all converted we will remove these from
-// this header
-#define HEAD_BYTE1  0xA3    // Decimal 163
-#define HEAD_BYTE2  0x95    // Decimal 149
-
-// structure used to define logging format
-struct LogStructure {
-    uint8_t msg_type;
-    uint8_t msg_len;
-    const char *name;
-    const char *format;
-    const char *labels;
-    const char *units;
-    const char *multipliers;
-};
-
-// maximum lengths of fields in LogStructure, including trailing nulls
-static const uint8_t LS_NAME_SIZE = 5;
-static const uint8_t LS_FORMAT_SIZE = 17;
-static const uint8_t LS_LABELS_SIZE = 65;
-static const uint8_t LS_UNITS_SIZE = 17;
-static const uint8_t LS_MULTIPLIERS_SIZE = 17;
-
-/*
-  log structures common to all vehicle types
+Format characters in the format string for binary log messages
+  a   : int16_t[32]
+  b   : int8_t
+  B   : uint8_t
+  h   : int16_t
+  H   : uint16_t
+  i   : int32_t
+  I   : uint32_t
+  f   : float
+  d   : double
+  n   : char[4]
+  N   : char[16]
+  Z   : char[64]
+  c   : int16_t * 100
+  C   : uint16_t * 100
+  e   : int32_t * 100
+  E   : uint32_t * 100
+  L   : int32_t latitude/longitude
+  M   : uint8_t flight mode
+  q   : int64_t
+  Q   : uint64_t
  */
-struct PACKED log_Format {
-    LOG_PACKET_HEADER;
-    uint8_t type;
-    uint8_t length;
-    char name[4];
-    char format[16];
-    char labels[64];
-};
-
-struct PACKED log_Unit {
-    LOG_PACKET_HEADER;
-    uint64_t time_us;
-    char type;
-    char unit[64]; // you know, this might be overkill...
-};
-
-struct PACKED log_Format_Multiplier {
-    LOG_PACKET_HEADER;
-    uint64_t time_us;
-    char type;
-    double multiplier;
-};
-
-struct PACKED log_Format_Units {
-    LOG_PACKET_HEADER;
-    uint64_t time_us;
-    uint8_t format_type;
-    char units[16];
-    char multipliers[16];
-};
 
 struct UnitStructure {
     const char ID;
@@ -140,6 +99,71 @@ const struct MultiplierStructure log_Multipliers[] = {
     { '/', 3600 }, // (ampere*second => ampere*hour)
 };
 
+/*
+  unfortunately these need to be macros because of a limitation of
+  named member structure initialisation in g++
+ */
+#define LOG_PACKET_HEADER	       uint8_t head1, head2, msgid;
+#define LOG_PACKET_HEADER_INIT(id) head1 : HEAD_BYTE1, head2 : HEAD_BYTE2, msgid : id
+#define LOG_PACKET_HEADER_LEN 3 // bytes required for LOG_PACKET_HEADER
+
+// once the logging code is all converted we will remove these from
+// this header
+#define HEAD_BYTE1  0xA3    // Decimal 163
+#define HEAD_BYTE2  0x95    // Decimal 149
+
+// structure used to define logging format
+struct LogStructure {
+    uint8_t msg_type;
+    uint8_t msg_len;
+    const char *name;
+    const char *format;
+    const char *labels;
+    const char *units;
+    const char *multipliers;
+};
+
+// maximum lengths of fields in LogStructure, including trailing nulls
+static const uint8_t LS_NAME_SIZE = 5;
+static const uint8_t LS_FORMAT_SIZE = 17;
+static const uint8_t LS_LABELS_SIZE = 65;
+static const uint8_t LS_UNITS_SIZE = 17;
+static const uint8_t LS_MULTIPLIERS_SIZE = 17;
+
+/*
+  log structures common to all vehicle types
+ */
+struct PACKED log_Format {
+    LOG_PACKET_HEADER;
+    uint8_t type;
+    uint8_t length;
+    char name[4];
+    char format[16];
+    char labels[64];
+};
+
+struct PACKED log_Unit {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    char type;
+    char unit[64]; // you know, this might be overkill...
+};
+
+struct PACKED log_Format_Multiplier {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    char type;
+    double multiplier;
+};
+
+struct PACKED log_Format_Units {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    uint8_t format_type;
+    char units[16];
+    char multipliers[16];
+};
+
 struct PACKED log_Parameter {
     LOG_PACKET_HEADER;
     uint64_t time_us;
@@ -1212,30 +1236,6 @@ struct PACKED log_Arm_Disarm {
 #define ARSP_UNITS "snPOPP----"
 #define ARSP_MULTS "F00B00----"
 
-/*
-Format characters in the format string for binary log messages
-  a   : int16_t[32]
-  b   : int8_t
-  B   : uint8_t
-  h   : int16_t
-  H   : uint16_t
-  i   : int32_t
-  I   : uint32_t
-  f   : float
-  d   : double
-  n   : char[4]
-  N   : char[16]
-  Z   : char[64]
-  c   : int16_t * 100
-  C   : uint16_t * 100
-  e   : int32_t * 100
-  E   : uint32_t * 100
-  L   : int32_t latitude/longitude
-  M   : uint8_t flight mode
-  q   : int64_t
-  Q   : uint64_t
- */
-
 // messages for all boards
 #define LOG_BASE_STRUCTURES \
     { LOG_FORMAT_MSG, sizeof(log_Format), \