diff --git a/conf/firmwares/subsystems/shared/gps_skytraq.makefile b/conf/firmwares/subsystems/shared/gps_skytraq.makefile
index 96a2a405f5..94a3f47223 100644
--- a/conf/firmwares/subsystems/shared/gps_skytraq.makefile
+++ b/conf/firmwares/subsystems/shared/gps_skytraq.makefile
@@ -4,7 +4,7 @@ GPS_LED ?= none
 SKYTRAQ_GPS_PORT_LOWER=$(shell echo $(GPS_PORT) | tr A-Z a-z)
 
 ap.CFLAGS += -DUSE_GPS
-ap.CFLAGS += -DGPS_LINK=$(SKYTRAQ_GPS_PORT_LOWER)
+ap.CFLAGS += -DSKYTRAQ_GPS_LINK=$(SKYTRAQ_GPS_PORT_LOWER)
 ap.CFLAGS += -DUSE_$(GPS_PORT)
 ap.CFLAGS += -D$(GPS_PORT)_BAUD=$(GPS_BAUD)
 
@@ -12,13 +12,13 @@ ifneq ($(GPS_LED),none)
   ap.CFLAGS += -DGPS_LED=$(GPS_LED)
 endif
 
-ap.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_skytraq.h\"
+ap.CFLAGS += -DPRIMARY_GPS_TYPE_H=\"subsystems/gps/gps_skytraq.h\"
 ap.srcs += $(SRC_SUBSYSTEMS)/gps/gps_skytraq.c
 
 $(TARGET).srcs += $(SRC_SUBSYSTEMS)/gps.c
 
 sim.CFLAGS += -DUSE_GPS
-sim.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_sim.h\"
+sim.CFLAGS += -DPRIMARY_GPS_TYPE_H=\"subsystems/gps/gps_sim.h\"
 sim.srcs += $(SRC_SUBSYSTEMS)/gps/gps_sim.c
 
 nps.CFLAGS += -DUSE_GPS
diff --git a/sw/airborne/subsystems/gps/gps_skytraq.c b/sw/airborne/subsystems/gps/gps_skytraq.c
index c450886421..1e95f4287e 100644
--- a/sw/airborne/subsystems/gps/gps_skytraq.c
+++ b/sw/airborne/subsystems/gps/gps_skytraq.c
@@ -20,6 +20,7 @@
  */
 
 #include "subsystems/gps.h"
+#include "subsystems/gps/gps_skytraq.h"
 #include "subsystems/abi.h"
 #include "led.h"
 
@@ -85,7 +86,7 @@ static inline uint16_t bswap16(uint16_t a)
 
 static int distance_too_great(struct EcefCoor_i *ecef_ref, struct EcefCoor_i *ecef_pos);
 
-void gps_impl_init(void)
+void skytraq_gps_impl_init(void)
 {
 
   gps_skytraq.status = UNINIT;
@@ -96,85 +97,96 @@ void gps_skytraq_msg(void)
 {
   // current timestamp
   uint32_t now_ts = get_sys_time_usec();
-  gps.last_msg_ticks = sys_time.nb_sec_rem;
-  gps.last_msg_time = sys_time.nb_sec;
+  gps_skytraq.state.last_msg_ticks = sys_time.nb_sec_rem;
+  gps_skytraq.state.last_msg_time = sys_time.nb_sec;
   gps_skytraq_read_message();
   if (gps_skytraq.msg_id == SKYTRAQ_ID_NAVIGATION_DATA) {
-    if (gps.fix == GPS_FIX_3D) {
-      gps.last_3dfix_ticks = sys_time.nb_sec_rem;
-      gps.last_3dfix_time = sys_time.nb_sec;
+    if (gps_skytraq.state.fix == GPS_FIX_3D) {
+      gps_skytraq.state.last_3dfix_ticks = sys_time.nb_sec_rem;
+      gps_skytraq.state.last_3dfix_time = sys_time.nb_sec;
     }
     AbiSendMsgGPS(GPS_SKYTRAQ_ID, now_ts, &gps);
   }
   gps_skytraq.msg_available = FALSE;
 }
 
+void skytraq_gps_event(void)
+{
+  struct link_device *dev = &((SKYTRAQ_GPS_LINK).device);
+
+  while (dev->char_available(dev->periph)) {
+    gps_skytraq_parse(dev->get_byte(dev->periph));
+    if (gps_skytraq.msg_available) {
+      gps_skytraq_msg();
+    }
+  }
+}
 
 void gps_skytraq_read_message(void)
 {
 
   if (gps_skytraq.msg_id == SKYTRAQ_ID_NAVIGATION_DATA) {
-    gps.ecef_pos.x  = SKYTRAQ_NAVIGATION_DATA_ECEFX(gps_skytraq.msg_buf);
-    gps.ecef_pos.y  = SKYTRAQ_NAVIGATION_DATA_ECEFY(gps_skytraq.msg_buf);
-    gps.ecef_pos.z  = SKYTRAQ_NAVIGATION_DATA_ECEFZ(gps_skytraq.msg_buf);
-    SetBit(gps.valid_fields, GPS_VALID_POS_ECEF_BIT);
+    gps_skytraq.state.ecef_pos.x  = SKYTRAQ_NAVIGATION_DATA_ECEFX(gps_skytraq.msg_buf);
+    gps_skytraq.state.ecef_pos.y  = SKYTRAQ_NAVIGATION_DATA_ECEFY(gps_skytraq.msg_buf);
+    gps_skytraq.state.ecef_pos.z  = SKYTRAQ_NAVIGATION_DATA_ECEFZ(gps_skytraq.msg_buf);
+    SetBit(gps_skytraq.state.valid_fields, GPS_VALID_POS_ECEF_BIT);
 
-    gps.ecef_vel.x  = SKYTRAQ_NAVIGATION_DATA_ECEFVX(gps_skytraq.msg_buf);
-    gps.ecef_vel.y  = SKYTRAQ_NAVIGATION_DATA_ECEFVY(gps_skytraq.msg_buf);
-    gps.ecef_vel.z  = SKYTRAQ_NAVIGATION_DATA_ECEFVZ(gps_skytraq.msg_buf);
-    SetBit(gps.valid_fields, GPS_VALID_VEL_ECEF_BIT);
+    gps_skytraq.state.ecef_vel.x  = SKYTRAQ_NAVIGATION_DATA_ECEFVX(gps_skytraq.msg_buf);
+    gps_skytraq.state.ecef_vel.y  = SKYTRAQ_NAVIGATION_DATA_ECEFVY(gps_skytraq.msg_buf);
+    gps_skytraq.state.ecef_vel.z  = SKYTRAQ_NAVIGATION_DATA_ECEFVZ(gps_skytraq.msg_buf);
+    SetBit(gps_skytraq.state.valid_fields, GPS_VALID_VEL_ECEF_BIT);
 
-    gps.lla_pos.lat = SKYTRAQ_NAVIGATION_DATA_LAT(gps_skytraq.msg_buf);
-    gps.lla_pos.lon = SKYTRAQ_NAVIGATION_DATA_LON(gps_skytraq.msg_buf);
-    gps.lla_pos.alt = SKYTRAQ_NAVIGATION_DATA_AEL(gps_skytraq.msg_buf) * 10;
-    SetBit(gps.valid_fields, GPS_VALID_POS_LLA_BIT);
+    gps_skytraq.state.lla_pos.lat = SKYTRAQ_NAVIGATION_DATA_LAT(gps_skytraq.msg_buf);
+    gps_skytraq.state.lla_pos.lon = SKYTRAQ_NAVIGATION_DATA_LON(gps_skytraq.msg_buf);
+    gps_skytraq.state.lla_pos.alt = SKYTRAQ_NAVIGATION_DATA_AEL(gps_skytraq.msg_buf) * 10;
+    SetBit(gps_skytraq.state.valid_fields, GPS_VALID_POS_LLA_BIT);
 
-    gps.hmsl        = SKYTRAQ_NAVIGATION_DATA_ASL(gps_skytraq.msg_buf) * 10;
-    SetBit(gps.valid_fields, GPS_VALID_HMSL_BIT);
+    gps_skytraq.state.hmsl        = SKYTRAQ_NAVIGATION_DATA_ASL(gps_skytraq.msg_buf) * 10;
+    SetBit(gps_skytraq.state.valid_fields, GPS_VALID_HMSL_BIT);
 
     //   pacc;
     //   sacc;
-    gps.pdop        = SKYTRAQ_NAVIGATION_DATA_PDOP(gps_skytraq.msg_buf);
-    gps.num_sv      = SKYTRAQ_NAVIGATION_DATA_NumSV(gps_skytraq.msg_buf);
-    gps.tow         = SKYTRAQ_NAVIGATION_DATA_TOW(gps_skytraq.msg_buf) * 10;
+    gps_skytraq.state.pdop        = SKYTRAQ_NAVIGATION_DATA_PDOP(gps_skytraq.msg_buf);
+    gps_skytraq.state.num_sv      = SKYTRAQ_NAVIGATION_DATA_NumSV(gps_skytraq.msg_buf);
+    gps_skytraq.state.tow         = SKYTRAQ_NAVIGATION_DATA_TOW(gps_skytraq.msg_buf) * 10;
 
     switch (SKYTRAQ_NAVIGATION_DATA_FixMode(gps_skytraq.msg_buf)) {
       case SKYTRAQ_FIX_3D_DGPS:
       case SKYTRAQ_FIX_3D:
-        gps.fix = GPS_FIX_3D;
+        gps_skytraq.state.fix = GPS_FIX_3D;
         break;
       case SKYTRAQ_FIX_2D:
-        gps.fix = GPS_FIX_2D;
+        gps_skytraq.state.fix = GPS_FIX_2D;
         break;
       default:
-        gps.fix = GPS_FIX_NONE;
+        gps_skytraq.state.fix = GPS_FIX_NONE;
     }
 
-    if (gps.fix == GPS_FIX_3D) {
-      if (distance_too_great(&gps_skytraq.ref_ltp.ecef, &gps.ecef_pos)) {
+    if (gps_skytraq.state.fix == GPS_FIX_3D) {
+      if (distance_too_great(&gps_skytraq.ref_ltp.ecef, &gps_skytraq.state.ecef_pos)) {
         // just grab current ecef_pos as reference.
-        ltp_def_from_ecef_i(&gps_skytraq.ref_ltp, &gps.ecef_pos);
+        ltp_def_from_ecef_i(&gps_skytraq.ref_ltp, &gps_skytraq.state.ecef_pos);
       }
       // convert ecef velocity vector to NED vector.
-      ned_of_ecef_vect_i(&gps.ned_vel, &gps_skytraq.ref_ltp, &gps.ecef_vel);
-      SetBit(gps.valid_fields, GPS_VALID_VEL_NED_BIT);
+      ned_of_ecef_vect_i(&gps_skytraq.state.ned_vel, &gps_skytraq.ref_ltp, &gps_skytraq.state.ecef_vel);
+      SetBit(gps_skytraq.state.valid_fields, GPS_VALID_VEL_NED_BIT);
 
       // ground course in radians
-      gps.course = (atan2f((float)gps.ned_vel.y, (float)gps.ned_vel.x)) * 1e7;
-      SetBit(gps.valid_fields, GPS_VALID_COURSE_BIT);
-      // GT: gps.cacc = ... ? what should course accuracy be?
+      gps_skytraq.state.course = (atan2f((float)gps_skytraq.state.ned_vel.y, (float)gps_skytraq.state.ned_vel.x)) * 1e7;
+      SetBit(gps_skytraq.state.valid_fields, GPS_VALID_COURSE_BIT);
+      // GT: gps_skytraq.state.cacc = ... ? what should course accuracy be?
 
       // ground speed
-      gps.gspeed = sqrt(gps.ned_vel.x * gps.ned_vel.x + gps.ned_vel.y * gps.ned_vel.y);
-      gps.speed_3d = sqrt(gps.ned_vel.x * gps.ned_vel.x + gps.ned_vel.y * gps.ned_vel.y + gps.ned_vel.z * gps.ned_vel.z);
+      gps_skytraq.state.gspeed = sqrt(gps_skytraq.state.ned_vel.x * gps_skytraq.state.ned_vel.x + gps_skytraq.state.ned_vel.y * gps_skytraq.state.ned_vel.y);
+      gps_skytraq.state.speed_3d = sqrt(gps_skytraq.state.ned_vel.x * gps_skytraq.state.ned_vel.x + gps_skytraq.state.ned_vel.y * gps_skytraq.state.ned_vel.y + gps_skytraq.state.ned_vel.z * gps_skytraq.state.ned_vel.z);
 
       // vertical speed (climb)
-      // solved by gps.ned.z?
+      // solved by gps_skytraq.state.ned.z?
     }
 
 
 #ifdef GPS_LED
-    if (gps.fix == GPS_FIX_3D) {
+    if (gps_skytraq.state.fix == GPS_FIX_3D) {
       LED_ON(GPS_LED);
     } else {
       LED_TOGGLE(GPS_LED);
@@ -273,3 +285,15 @@ static int distance_too_great(struct EcefCoor_i *ecef_ref, struct EcefCoor_i *ec
 
   return FALSE;
 }
+
+/*
+ * register callbacks & structs
+ */
+void skytraq_gps_register(void)
+{
+#ifdef GPS_SECONDARY_PIKSI
+  gps_register_impl(skytraq_gps_impl_init, skytraq_gps_event, GPS_SKYTRAQ_ID, 1);
+#else
+  gps_register_impl(skytraq_gps_impl_init, skytraq_gps_event, GPS_SKYTRAQ_ID, 0);
+#endif
+}
diff --git a/sw/airborne/subsystems/gps/gps_skytraq.h b/sw/airborne/subsystems/gps/gps_skytraq.h
index 8e51e2da13..3190388ffe 100644
--- a/sw/airborne/subsystems/gps/gps_skytraq.h
+++ b/sw/airborne/subsystems/gps/gps_skytraq.h
@@ -26,6 +26,22 @@
 
 #define SKYTRAQ_ID_NAVIGATION_DATA 0XA8
 
+#if GPS_SECONDARY_SKYTRAQ
+#ifndef SKYTRAQ_GPS_LINK
+#define SKYTRAQ_GPS_LINK GPS_SECONDARY_PORT
+#define SecondaryGpsImpl skytraq
+#endif
+#else
+#ifndef PrimaryGpsImpl
+#define PrimaryGpsImpl skytraq
+#endif
+#endif
+#if GPS_PRIMARY_SKYTRAQ
+#ifndef SKYTRAQ_GPS_LINK
+#define SKYTRAQ_GPS_LINK GPS_PRIMARY_PORT
+#endif
+#endif
+
 /* last error type */
 enum GpsSkytraqError {
   GPS_SKYTRAQ_ERR_NONE = 0,
@@ -50,6 +66,8 @@ struct GpsSkytraq {
   enum GpsSkytraqError error_last;
 
   struct LtpDef_i ref_ltp;
+
+  struct GpsState state;
 };
 
 extern struct GpsSkytraq gps_skytraq;
@@ -63,17 +81,8 @@ extern struct GpsSkytraq gps_skytraq;
 extern void gps_skytraq_read_message(void);
 extern void gps_skytraq_parse(uint8_t c);
 extern void gps_skytraq_msg(void);
-
-static inline void GpsEvent(void)
-{
-  struct link_device *dev = &((GPS_LINK).device);
-
-  while (dev->char_available(dev->periph)) {
-    gps_skytraq_parse(dev->get_byte(dev->periph));
-    if (gps_skytraq.msg_available) {
-      gps_skytraq_msg();
-    }
-  }
-}
+extern void skytraq_gps_register(void);
+void skytraq_gps_impl_init(void);
+void skytraq_gps_event(void);
 
 #endif /* GPS_SKYTRAQ_H */