diff --git a/inc/gps.h b/inc/gps.h
--- a/inc/gps.h
+++ b/inc/gps.h
@@ -29,22 +29,17 @@
 
 #include <stdint.h>
 
-// Hardware config
-/*#define GPS_USART USART1
-#define GPS_IRQ NVIC_USART1_IRQ
-
-#define GPS_TX_PORT GPIOB
-#define GPS_TX_PIN GPIO6
-#define GPS_TX_AF GPIO_AF0
+// Duration before GPS fix is declared stale
+#define GPS_STALEFIX_MS 60000
 
-#define GPS_RX_PORT GPIOB
-#define GPS_RX_PIN GPIO7
-#define GPS_RX_AF GPIO_AF0
+enum gps_state
+{
+    GPS_STATE_ACQUIRING = 0,
+    GPS_STATE_FRESHFIX,
+    GPS_STATE_STALEFIX,
+    GPS_STATE_NOFIX
+};
 
-#define GPS_ONOFF_PORT GPIOA
-#define GPS_ONOFF_PIN GPIO1
-#define GPS_ONOFF GPS_ONOFF_PORT, GPS_ONOFF_PIN
-*/
 // Messages (REMOVEME?)
 #define GGA_MESSAGE
 #define RMC_MESSAGE
@@ -63,9 +58,13 @@ char* get_gpsaltitude(void);
 char* get_speedKnots(void);
 char* get_course(void);
 char* get_hdop(void);
+uint16_t get_hdop_int_tenths(void);
 char* get_sv(void);
 char* get_dayofmonth(void);
 uint8_t gps_hasfix(void);
+void gps_process(void);
+uint8_t gps_getstate(void);
+void gps_acquirefix(void);
 void parse_gps_transmission(void);
 void XORbyteWithChecksum(uint8_t byte);