From 28c044f95f9f473945ecc3d81229314142cb1e5c Mon Sep 17 00:00:00 2001
From: Richard Meadows <richardeoin@gmail.com>
Date: Thu, 25 Jun 2015 19:49:47 +0100
Subject: [PATCH] Added altitude to aprs geofence. APRS always enabled below
 200m

---
 firmware/inc/location.h          |  2 +-
 firmware/src/location.c          | 12 +++++++++---
 firmware/src/main.c              |  2 +-
 firmware/test/tc/location_aprs.h |  2 +-
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/firmware/inc/location.h b/firmware/inc/location.h
index 9522c62..487589c 100644
--- a/firmware/inc/location.h
+++ b/firmware/inc/location.h
@@ -32,6 +32,6 @@ bool latlon_in_aprs_zone(int32_t aprs_zone, int32_t aprs_zone_outline, float lon
 bool aprs_location_tx_allow(void);
 int32_t aprs_location_frequency(void);
 
-void aprs_location_update(float lon, float lat);
+void aprs_location_update(float lon, float lat, uint32_t altitude);
 
 #endif /* LOCATION_H */
diff --git a/firmware/src/location.c b/firmware/src/location.c
index 71a4a16..36f514d 100644
--- a/firmware/src/location.c
+++ b/firmware/src/location.c
@@ -30,6 +30,7 @@
 #include "geofence_aprs.h"
 
 int32_t current_aprs_zone = -2, current_aprs_zone_outline = -2;
+uint32_t _altitude = 0;
 
 #define polyX(i)	(poly[(i*2)+0])
 #define polyY(i)	(poly[(i*2)+1])
@@ -97,8 +98,10 @@ bool latlon_in_aprs_zone(int32_t aprs_zone, int32_t aprs_zone_outline, float lon
  */
 bool aprs_location_tx_allow(void) {
 
-  /* Not in any zone, or in a zone other than Alpha */
-  return (current_aprs_zone == -1) || (current_aprs_zone > 0);
+  /* Not in any zone, or in a zone other than Alpha, or not airbourne */
+  return (current_aprs_zone == -1) ||
+    (current_aprs_zone > 0) ||
+    (_altitude < 200);
 }
 /**
  * Returns the aprs frequency in the current zone.
@@ -118,10 +121,13 @@ int32_t aprs_location_frequency(void) {
 /**
  * Updates the aprs location based on the current lat/lon
  */
-void aprs_location_update(float lon, float lat) {
+void aprs_location_update(float lon, float lat, uint32_t altitude) {
 
   uint32_t z, outline;
 
+  /* Record altitude */
+  _altitude = altitude;
+
   /* Were we in an aprs zone last time? */
   if (current_aprs_zone >= 0 && current_aprs_zone_outline >= 0) {
 
diff --git a/firmware/src/main.c b/firmware/src/main.c
index 3532a45..88ab83b 100644
--- a/firmware/src/main.c
+++ b/firmware/src/main.c
@@ -191,7 +191,7 @@ void aprs_telemetry(void) {
   uint32_t altitude = pos.payload.height / 1000;
 
   /* Update location */
-  aprs_location_update(lon, lat);
+  aprs_location_update(lon, lat, altitude);
 
   /* aprs okay here? */
   if (aprs_location_tx_allow()) {
diff --git a/firmware/test/tc/location_aprs.h b/firmware/test/tc/location_aprs.h
index 10a10e3..8f3c062 100644
--- a/firmware/test/tc/location_aprs.h
+++ b/firmware/test/tc/location_aprs.h
@@ -21,7 +21,7 @@ struct location_aprs_tc_results {
 /* Function */
 __verification__ void location_aprs_tc(void) {
 
-  aprs_location_update(location_aprs_tc_params.lon, location_aprs_tc_params.lat);
+  aprs_location_update(location_aprs_tc_params.lon, location_aprs_tc_params.lat, 0);
 
   location_aprs_tc_results.tx_allow = aprs_location_tx_allow();
   location_aprs_tc_results.frequency = aprs_location_frequency();