diff --git a/src/main/blackbox/blackbox.c b/src/main/blackbox/blackbox.c
index 325aa5b297..46a1bb9135 100644
--- a/src/main/blackbox/blackbox.c
+++ b/src/main/blackbox/blackbox.c
@@ -977,7 +977,7 @@ static void writeGPSFrame(timeUs_t currentTimeUs)
     blackboxWriteUnsignedVB(gpsSol.numSat);
     blackboxWriteSignedVB(gpsSol.llh.lat - gpsHistory.GPS_home[LAT]);
     blackboxWriteSignedVB(gpsSol.llh.lon - gpsHistory.GPS_home[LON]);
-    blackboxWriteUnsignedVB(gpsSol.llh.alt);
+    blackboxWriteUnsignedVB(gpsSol.llh.altCm / 10); // was originally designed to transport meters in int16, but +-3276.7m is a good compromise
     blackboxWriteUnsignedVB(gpsSol.groundSpeed);
     blackboxWriteUnsignedVB(gpsSol.groundCourse);
 
diff --git a/src/main/flight/gps_rescue.c b/src/main/flight/gps_rescue.c
index 76c972e987..74d145e9bf 100644
--- a/src/main/flight/gps_rescue.c
+++ b/src/main/flight/gps_rescue.c
@@ -58,8 +58,8 @@ PG_REGISTER_WITH_RESET_TEMPLATE(gpsRescueConfig_t, gpsRescueConfig, PG_GPS_RESCU
 
 PG_RESET_TEMPLATE(gpsRescueConfig_t, gpsRescueConfig,
     .angle = 32,
-    .initialAltitude = 50,
-    .descentDistance = 200,
+    .initialAltitudeM = 50,
+    .descentDistanceM = 200,
     .rescueGroundspeed = 2000,
     .throttleP = 150,
     .throttleI = 20,
@@ -125,8 +125,8 @@ void updateGPSRescueState(void)
         }
 
         // Minimum distance detection.  Disarm regardless of sanity check configuration.  Rescue too close is never a good idea.
-        if (rescueState.sensor.distanceToHome < gpsRescueConfig()->minRescueDth) {
-            // Never allow rescue mode to engage as a failsafe  when too close or when disarmed.
+        if (rescueState.sensor.distanceToHomeM < gpsRescueConfig()->minRescueDth) {
+            // Never allow rescue mode to engage as a failsafe when too close or when disarmed.
             if (rescueState.isFailsafe || !ARMING_FLAG(ARMED)) {
                 rescueState.failure = RESCUE_TOO_CLOSE;
                 setArmingDisabled(ARMING_DISABLED_ARM_SWITCH);
@@ -141,40 +141,40 @@ void updateGPSRescueState(void)
         FALLTHROUGH;
     case RESCUE_ATTAIN_ALT:
         // Get to a safe altitude at a low velocity ASAP
-        if (ABS(rescueState.intent.targetAltitude - rescueState.sensor.currentAltitude) < 1000) {
+        if (ABS(rescueState.intent.targetAltitudeCm - rescueState.sensor.currentAltitudeCm) < 1000) {
             rescueState.phase = RESCUE_CROSSTRACK;
         }
 
         rescueState.intent.targetGroundspeed = 500;
-        rescueState.intent.targetAltitude = MAX(gpsRescueConfig()->initialAltitude * 100, rescueState.sensor.maxAltitude + 1500);
+        rescueState.intent.targetAltitudeCm = MAX(gpsRescueConfig()->initialAltitudeM * 100, rescueState.sensor.maxAltitudeCm + 1500);
         rescueState.intent.crosstrack = true;
         rescueState.intent.minAngleDeg = 10;
         rescueState.intent.maxAngleDeg = 15;
         break;
     case RESCUE_CROSSTRACK:
-        if (rescueState.sensor.distanceToHome < gpsRescueConfig()->descentDistance) {
+        if (rescueState.sensor.distanceToHomeM < gpsRescueConfig()->descentDistanceM) {
             rescueState.phase = RESCUE_LANDING_APPROACH;
         }
 
         // We can assume at this point that we are at or above our RTH height, so we need to try and point to home and tilt while maintaining alt
         // Is our altitude way off?  We should probably kick back to phase RESCUE_ATTAIN_ALT
         rescueState.intent.targetGroundspeed = gpsRescueConfig()->rescueGroundspeed;
-        rescueState.intent.targetAltitude = MAX(gpsRescueConfig()->initialAltitude * 100, rescueState.sensor.maxAltitude + 1500);
+        rescueState.intent.targetAltitudeCm = MAX(gpsRescueConfig()->initialAltitudeM * 100, rescueState.sensor.maxAltitudeCm + 1500);
         rescueState.intent.crosstrack = true;
         rescueState.intent.minAngleDeg = 15;
         rescueState.intent.maxAngleDeg = gpsRescueConfig()->angle;
         break;
     case RESCUE_LANDING_APPROACH:
         // We are getting close to home in the XY plane, get Z where it needs to be to move to landing phase
-        if (rescueState.sensor.distanceToHome < 10 && rescueState.sensor.currentAltitude <= 1000) {
+        if (rescueState.sensor.distanceToHomeM < 10 && rescueState.sensor.currentAltitudeCm <= 1000) {
             rescueState.phase = RESCUE_LANDING;
         }
 
         // Only allow new altitude and new speed to be equal or lower than the current values (to prevent parabolic movement on overshoot)
-        int32_t newAlt = gpsRescueConfig()->initialAltitude * 100  * rescueState.sensor.distanceToHome / gpsRescueConfig()->descentDistance;
-        int32_t newSpeed = gpsRescueConfig()->rescueGroundspeed * rescueState.sensor.distanceToHome / gpsRescueConfig()->descentDistance;
+        int32_t newAlt = gpsRescueConfig()->initialAltitudeM * 100  * rescueState.sensor.distanceToHomeM / gpsRescueConfig()->descentDistanceM;
+        int32_t newSpeed = gpsRescueConfig()->rescueGroundspeed * rescueState.sensor.distanceToHomeM / gpsRescueConfig()->descentDistanceM;
 
-        rescueState.intent.targetAltitude = constrain(newAlt, 100, rescueState.intent.targetAltitude);
+        rescueState.intent.targetAltitudeCm = constrain(newAlt, 100, rescueState.intent.targetAltitudeCm);
         rescueState.intent.targetGroundspeed = constrain(newSpeed, 100, rescueState.intent.targetGroundspeed);
         rescueState.intent.crosstrack = true;
         rescueState.intent.minAngleDeg = 10;
@@ -192,7 +192,7 @@ void updateGPSRescueState(void)
         }
 
         rescueState.intent.targetGroundspeed = 0;
-        rescueState.intent.targetAltitude = 0;
+        rescueState.intent.targetAltitudeCm = 0;
         rescueState.intent.crosstrack = true;
         rescueState.intent.minAngleDeg = 0;
         rescueState.intent.maxAngleDeg = 15;
@@ -220,28 +220,28 @@ void updateGPSRescueState(void)
 
 void sensorUpdate()
 {
-    rescueState.sensor.currentAltitude = getEstimatedAltitude();
+    rescueState.sensor.currentAltitudeCm = getEstimatedAltitudeCm();
 
     // Calculate altitude velocity
     static uint32_t previousTimeUs;
-    static int32_t previousAltitude;
+    static int32_t previousAltitudeCm;
 
     const uint32_t currentTimeUs = micros();
     const float dTime = currentTimeUs - previousTimeUs;
 
     if (newGPSData) { // Calculate velocity at lowest common denominator
-        rescueState.sensor.distanceToHome = GPS_distanceToHome;
+        rescueState.sensor.distanceToHomeM = GPS_distanceToHome;
         rescueState.sensor.directionToHome = GPS_directionToHome;
         rescueState.sensor.numSat = gpsSol.numSat;
         rescueState.sensor.groundSpeed = gpsSol.groundSpeed;
 
-        rescueState.sensor.zVelocity = (rescueState.sensor.currentAltitude - previousAltitude) * 1000000.0f / dTime;
+        rescueState.sensor.zVelocity = (rescueState.sensor.currentAltitudeCm - previousAltitudeCm) * 1000000.0f / dTime;
         rescueState.sensor.zVelocityAvg = 0.8f * rescueState.sensor.zVelocityAvg + rescueState.sensor.zVelocity * 0.2f;
 
         rescueState.sensor.accMagnitude = (float) sqrtf(sq(acc.accADC[Z]) + sq(acc.accADC[X]) + sq(acc.accADC[Y])) * acc.dev.acc_1G_rec;
         rescueState.sensor.accMagnitudeAvg = (rescueState.sensor.accMagnitudeAvg * 0.8f) + (rescueState.sensor.accMagnitude * 0.2f);
 
-        previousAltitude = rescueState.sensor.currentAltitude;
+        previousAltitudeCm = rescueState.sensor.currentAltitudeCm;
         previousTimeUs = currentTimeUs;
     }
 }
@@ -327,9 +327,9 @@ void idleTasks()
     gpsRescueAngle[AI_ROLL] = 0;
 
     // Store the max altitude we see not during RTH so we know our fly-back minimum alt
-    rescueState.sensor.maxAltitude = MAX(rescueState.sensor.currentAltitude, rescueState.sensor.maxAltitude);
+    rescueState.sensor.maxAltitudeCm = MAX(rescueState.sensor.currentAltitudeCm, rescueState.sensor.maxAltitudeCm);
     // Store the max distance to home during normal flight so we know if a flyaway is happening
-    rescueState.sensor.maxDistanceToHome = MAX(rescueState.sensor.distanceToHome, rescueState.sensor.maxDistanceToHome);
+    rescueState.sensor.maxDistanceToHomeM = MAX(rescueState.sensor.distanceToHomeM, rescueState.sensor.maxDistanceToHomeM);
 
     rescueThrottle = rcCommand[THROTTLE];
 
@@ -391,7 +391,7 @@ void rescueAttainPosition()
     static float previousAltitudeError = 0;
     static int16_t altitudeIntegral = 0;
 
-    const int16_t altitudeError = (rescueState.intent.targetAltitude - rescueState.sensor.currentAltitude) / 100; // Error in meters
+    const int16_t altitudeError = (rescueState.intent.targetAltitudeCm - rescueState.sensor.currentAltitudeCm) / 100; // Error in meters
     const int16_t altitudeDerivative = altitudeError - previousAltitudeError;
 
     // Only allow integral windup within +-15m absolute altitude error
diff --git a/src/main/flight/gps_rescue.h b/src/main/flight/gps_rescue.h
index ea7ba327b3..dba47f39f8 100644
--- a/src/main/flight/gps_rescue.h
+++ b/src/main/flight/gps_rescue.h
@@ -27,8 +27,8 @@ typedef enum {
 
 typedef struct gpsRescue_s {
     uint16_t angle; //degrees
-    uint16_t initialAltitude; //meters
-    uint16_t descentDistance; //meters
+    uint16_t initialAltitudeM; //meters
+    uint16_t descentDistanceM; //meters
     uint16_t rescueGroundspeed; // centimeters per second
     uint16_t throttleP, throttleI, throttleD;
     uint16_t yawP;
@@ -62,7 +62,7 @@ typedef enum {
 } rescueFailureState_e;
 
 typedef struct {
-    int32_t targetAltitude;
+    int32_t targetAltitudeCm;
     int32_t targetGroundspeed;
     uint8_t minAngleDeg;
     uint8_t maxAngleDeg;
@@ -70,10 +70,10 @@ typedef struct {
 } rescueIntent_s;
 
 typedef struct {
-    int32_t maxAltitude;
-    int32_t currentAltitude;
-    uint16_t distanceToHome;
-    uint16_t maxDistanceToHome;
+    int32_t maxAltitudeCm;
+    int32_t currentAltitudeCm;
+    uint16_t distanceToHomeM;
+    uint16_t maxDistanceToHomeM;
     int16_t directionToHome;
     uint16_t groundSpeed;
     uint8_t numSat;
diff --git a/src/main/flight/position.c b/src/main/flight/position.c
index 771baa0f04..8b0c716ec5 100644
--- a/src/main/flight/position.c
+++ b/src/main/flight/position.c
@@ -38,7 +38,7 @@
 #include "sensors/sensors.h"
 #include "sensors/barometer.h"
 
-static int32_t estimatedAltitude = 0;                // in cm
+static int32_t estimatedAltitudeCm = 0;                // in cm
 
 #define BARO_UPDATE_FREQUENCY_40HZ (1000 * 25)
 
@@ -77,7 +77,7 @@ void calculateEstimatedAltitude(timeUs_t currentTimeUs)
 
 #ifdef USE_GPS
 if (sensors(SENSOR_GPS) && STATE(GPS_FIX)) {
-    gpsAlt = gpsSol.llh.alt;
+    gpsAlt = gpsSol.llh.altCm;
     haveGpsAlt = true;
 
     if (gpsSol.hdop != 0) {
@@ -99,11 +99,11 @@ if (sensors(SENSOR_GPS) && STATE(GPS_FIX)) {
     gpsAlt -= gpsAltOffset;
     
     if (haveGpsAlt && haveBaroAlt) {
-        estimatedAltitude = gpsAlt * gpsTrust + baroAlt * (1 - gpsTrust);
+        estimatedAltitudeCm = gpsAlt * gpsTrust + baroAlt * (1 - gpsTrust);
     } else if (haveGpsAlt) {
-        estimatedAltitude = gpsAlt;
+        estimatedAltitudeCm = gpsAlt;
     } else if (haveBaroAlt) {
-        estimatedAltitude = baroAlt;
+        estimatedAltitudeCm = baroAlt;
     }
     
     DEBUG_SET(DEBUG_ALTITUDE, 0, (int32_t)(100 * gpsTrust));
@@ -117,9 +117,9 @@ bool isAltitudeOffset(void)
 }
 #endif
 
-int32_t getEstimatedAltitude(void)
+int32_t getEstimatedAltitudeCm(void)
 {
-    return estimatedAltitude;
+    return estimatedAltitudeCm;
 }
 
 // This should be removed or fixed, but it would require changing a lot of other things to get rid of.
diff --git a/src/main/flight/position.h b/src/main/flight/position.h
index c7b98173b4..70a7bfc1c7 100644
--- a/src/main/flight/position.h
+++ b/src/main/flight/position.h
@@ -24,5 +24,5 @@
 
 bool isAltitudeOffset(void);
 void calculateEstimatedAltitude(timeUs_t currentTimeUs);
-int32_t getEstimatedAltitude(void);
+int32_t getEstimatedAltitudeCm(void);
 int16_t getEstimatedVario(void);
\ No newline at end of file
diff --git a/src/main/interface/msp.c b/src/main/interface/msp.c
index e2aecb14d5..ab195a6ba0 100644
--- a/src/main/interface/msp.c
+++ b/src/main/interface/msp.c
@@ -920,7 +920,7 @@ static bool mspProcessOutCommand(uint8_t cmdMSP, sbuf_t *dst)
 
     case MSP_ALTITUDE:
 #if defined(USE_BARO) || defined(USE_RANGEFINDER)
-        sbufWriteU32(dst, getEstimatedAltitude());
+        sbufWriteU32(dst, getEstimatedAltitudeCm());
 #else
         sbufWriteU32(dst, 0);
 #endif
@@ -1045,7 +1045,7 @@ static bool mspProcessOutCommand(uint8_t cmdMSP, sbuf_t *dst)
         sbufWriteU8(dst, gpsSol.numSat);
         sbufWriteU32(dst, gpsSol.llh.lat);
         sbufWriteU32(dst, gpsSol.llh.lon);
-        sbufWriteU16(dst, (uint16_t)constrain(gpsSol.llh.alt / 100, 0, UINT16_MAX)); // alt changed from 1m to 0.01m per lsb since MSP API 1.39 by RTH. To maintain backwards compatibility compensate to 1m per lsb in MSP again.
+        sbufWriteU16(dst, (uint16_t)constrain(gpsSol.llh.altCm / 100, 0, UINT16_MAX)); // alt changed from 1m to 0.01m per lsb since MSP API 1.39 by RTH. To maintain backwards compatibility compensate to 1m per lsb in MSP again.
         sbufWriteU16(dst, gpsSol.groundSpeed);
         sbufWriteU16(dst, gpsSol.groundCourse);
         break;
@@ -2109,7 +2109,7 @@ static mspResult_e mspProcessInCommand(uint8_t cmdMSP, sbuf_t *src)
         gpsSol.numSat = sbufReadU8(src);
         gpsSol.llh.lat = sbufReadU32(src);
         gpsSol.llh.lon = sbufReadU32(src);
-        gpsSol.llh.alt = sbufReadU16(src) * 100; // alt changed from 1m to 0.01m per lsb since MSP API 1.39 by RTH. Received MSP altitudes in 1m per lsb have to upscaled.
+        gpsSol.llh.altCm = sbufReadU16(src) * 100; // alt changed from 1m to 0.01m per lsb since MSP API 1.39 by RTH. Received MSP altitudes in 1m per lsb have to upscaled.
         gpsSol.groundSpeed = sbufReadU16(src);
         GPS_update |= 2;        // New data signalisation to GPS functions // FIXME Magic Numbers
         break;
diff --git a/src/main/interface/settings.c b/src/main/interface/settings.c
index a0ed8a0990..2f1f444cb3 100644
--- a/src/main/interface/settings.c
+++ b/src/main/interface/settings.c
@@ -752,8 +752,8 @@ const clivalue_t valueTable[] = {
 #ifdef USE_GPS_RESCUE
     // PG_GPS_RESCUE
     { "gps_rescue_angle",           VAR_UINT16 | MASTER_VALUE, .config.minmax = { 0, 200 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, angle) },
-    { "gps_rescue_initial_alt",     VAR_UINT16 | MASTER_VALUE, .config.minmax = { 20, 100 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, initialAltitude) },
-    { "gps_rescue_descent_dist",    VAR_UINT16 | MASTER_VALUE, .config.minmax = { 30, 500 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, descentDistance) },
+    { "gps_rescue_initial_alt",     VAR_UINT16 | MASTER_VALUE, .config.minmax = { 20, 100 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, initialAltitudeM) },
+    { "gps_rescue_descent_dist",    VAR_UINT16 | MASTER_VALUE, .config.minmax = { 30, 500 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, descentDistanceM) },
     { "gps_rescue_ground_speed",    VAR_UINT16 | MASTER_VALUE, .config.minmax = { 30, 3000 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, rescueGroundspeed) },
     { "gps_rescue_throttle_p",      VAR_UINT16 | MASTER_VALUE, .config.minmax = { 0, 500 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, throttleP) },
     { "gps_rescue_throttle_i",      VAR_UINT16 | MASTER_VALUE, .config.minmax = { 0, 500 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, throttleI) },
diff --git a/src/main/io/gps.c b/src/main/io/gps.c
index edd1853e10..19c0ad0447 100644
--- a/src/main/io/gps.c
+++ b/src/main/io/gps.c
@@ -673,7 +673,7 @@ typedef struct gpsDataNmea_s {
     int32_t latitude;
     int32_t longitude;
     uint8_t numSat;
-    int32_t altitude;
+    int32_t altitudeCm;
     uint16_t speed;
     uint16_t hdop;
     uint16_t ground_course;
@@ -745,7 +745,7 @@ static bool gpsNewFrameNMEA(char c)
                             gps_Msg.hdop = grab_fields(string, 1) * 100;          // hdop
                             break;
                         case 9:
-                            gps_Msg.altitude = grab_fields(string, 1) * 10;     // altitude in centimeters. Note: NMEA delivers altitude with 1 or 3 decimals. It's safer to cut at 0.1m and multiply by 10
+                            gps_Msg.altitudeCm = grab_fields(string, 1) * 10;     // altitude in centimeters. Note: NMEA delivers altitude with 1 or 3 decimals. It's safer to cut at 0.1m and multiply by 10
                             break;
                     }
                     break;
@@ -836,7 +836,7 @@ static bool gpsNewFrameNMEA(char c)
                             gpsSol.llh.lat = gps_Msg.latitude;
                             gpsSol.llh.lon = gps_Msg.longitude;
                             gpsSol.numSat = gps_Msg.numSat;
-                            gpsSol.llh.alt = gps_Msg.altitude;
+                            gpsSol.llh.altCm = gps_Msg.altitudeCm;
                             gpsSol.hdop = gps_Msg.hdop;
                         }
                         break;
@@ -891,7 +891,7 @@ typedef struct {
     int32_t longitude;
     int32_t latitude;
     int32_t altitude_ellipsoid;
-    int32_t altitude_msl;
+    int32_t altitudeMslMm;
     uint32_t horizontal_accuracy;
     uint32_t vertical_accuracy;
 } ubx_nav_posllh;
@@ -1060,7 +1060,7 @@ static bool UBLOX_parse_gps(void)
         //i2c_dataset.time                = _buffer.posllh.time;
         gpsSol.llh.lon = _buffer.posllh.longitude;
         gpsSol.llh.lat = _buffer.posllh.latitude;
-        gpsSol.llh.alt = _buffer.posllh.altitude_msl / 10;  //alt in cm
+        gpsSol.llh.altCm = _buffer.posllh.altitudeMslMm / 10;  //alt in cm
         if (next_fix) {
             ENABLE_STATE(GPS_FIX);
         } else {
diff --git a/src/main/io/gps.h b/src/main/io/gps.h
index d9bbf9a655..cc35885f29 100644
--- a/src/main/io/gps.h
+++ b/src/main/io/gps.h
@@ -86,7 +86,7 @@ typedef struct gpsCoordinateDDDMMmmmm_s {
 typedef struct gpsLocation_s {
     int32_t lat;                    // latitude * 1e+7
     int32_t lon;                    // longitude * 1e+7
-    int32_t alt;                    // altitude in 0.01m
+    int32_t altCm;                  // altitude in 0.01m
 } gpsLocation_t;
 
 typedef struct gpsSolutionData_s {
diff --git a/src/main/io/osd.c b/src/main/io/osd.c
index 2558627059..623fcbd44d 100644
--- a/src/main/io/osd.c
+++ b/src/main/io/osd.c
@@ -284,9 +284,9 @@ static char osdGetTemperatureSymbolForSelectedUnit(void)
 }
 #endif
 
-static void osdFormatAltitudeString(char * buff, int altitude)
+static void osdFormatAltitudeString(char * buff, int32_t altitudeCm)
 {
-    const int alt = osdGetMetersToSelectedUnit(altitude) / 10;
+    const int alt = osdGetMetersToSelectedUnit(altitudeCm) / 10;
 
     tfp_sprintf(buff, "%5d %c", alt, osdGetMetersToSelectedUnitSymbol());
     buff[5] = buff[4];
@@ -564,7 +564,7 @@ static bool osdDrawSingleElement(uint8_t item)
         break;
 
     case OSD_ALTITUDE:
-        osdFormatAltitudeString(buff, getEstimatedAltitude());
+        osdFormatAltitudeString(buff, getEstimatedAltitudeCm());
         break;
 
     case OSD_ITEM_TIMER_1:
@@ -1140,7 +1140,7 @@ void osdUpdateAlarms(void)
 {
     // This is overdone?
 
-    int32_t alt = osdGetMetersToSelectedUnit(getEstimatedAltitude()) / 100;
+    int32_t alt = osdGetMetersToSelectedUnit(getEstimatedAltitudeCm()) / 100;
 
     if (getRssiPercent() < osdConfig()->rssi_alarm) {
         SET_BLINK(OSD_RSSI_VALUE);
@@ -1273,9 +1273,9 @@ static void osdUpdateStats(void)
         stats.min_rssi = value;
     }
 
-    int altitude = getEstimatedAltitude();
-    if (stats.max_altitude < altitude) {
-        stats.max_altitude = altitude;
+    int32_t altitudeCm = getEstimatedAltitudeCm();
+    if (stats.max_altitude < altitudeCm) {
+        stats.max_altitude = altitudeCm;
     }
 
     if (stats.max_g_force < osdGForce) {
diff --git a/src/main/target/COLIBRI_RACE/i2c_bst.c b/src/main/target/COLIBRI_RACE/i2c_bst.c
index 78b956a523..cf2f4f6058 100644
--- a/src/main/target/COLIBRI_RACE/i2c_bst.c
+++ b/src/main/target/COLIBRI_RACE/i2c_bst.c
@@ -796,23 +796,23 @@ static void bstMasterWrite32(uint32_t data)
 
 static int32_t lat = 0;
 static int32_t lon = 0;
-static uint16_t alt = 0;
+static uint16_t altM = 0;
 static uint8_t numOfSat = 0;
 #endif
 
 #ifdef USE_GPS
 bool writeGpsPositionPrameToBST(void)
 {
-    if ((lat != gpsSol.llh.lat) || (lon != gpsSol.llh.lon) || (alt != gpsSol.llh.alt) || (numOfSat != gpsSol.numSat)) {
+    if ((lat != gpsSol.llh.lat) || (lon != gpsSol.llh.lon) || (alt != (gpsSol.llh.altCm / 100)) || (numOfSat != gpsSol.numSat)) {
         lat = gpsSol.llh.lat;
         lon = gpsSol.llh.lon;
-        alt = gpsSol.llh.alt;
+        altM = gpsSol.llh.altCm / 100;
         numOfSat = gpsSol.numSat;
         uint16_t speed = (gpsSol.groundSpeed * 9 / 25);
         uint16_t gpsHeading = 0;
         uint16_t altitude = 0;
         gpsHeading = gpsSol.groundCourse * 10;
-        altitude = alt * 10 + 1000;
+        altitude = altM + 1000;  // To be verified: in m +1000m offset for neg. altitudes?
 
         bstMasterStartBuffer(PUBLIC_ADDRESS);
         bstMasterWrite8(GPS_POSITION_FRAME_ID);
diff --git a/src/main/telemetry/crsf.c b/src/main/telemetry/crsf.c
index 7b46487219..6f9fd09254 100644
--- a/src/main/telemetry/crsf.c
+++ b/src/main/telemetry/crsf.c
@@ -49,6 +49,7 @@
 #include "fc/runtime_config.h"
 
 #include "flight/imu.h"
+#include "flight/position.h"
 
 #include "interface/crsf_protocol.h"
 
@@ -181,8 +182,7 @@ void crsfFrameGps(sbuf_t *dst)
     sbufWriteU32BigEndian(dst, gpsSol.llh.lon);
     sbufWriteU16BigEndian(dst, (gpsSol.groundSpeed * 36 + 5) / 10); // gpsSol.groundSpeed is in 0.1m/s
     sbufWriteU16BigEndian(dst, gpsSol.groundCourse * 10); // gpsSol.groundCourse is degrees * 10
-    //Send real GPS altitude only if it's reliable (there's a GPS fix)
-    const uint16_t altitude = (STATE(GPS_FIX) ? gpsSol.llh.alt / 100 : 0) + 1000;
+    const uint16_t altitude = (constrain(getEstimatedAltitudeCm(), 0 * 100, 5000 * 100) / 100) + 1000; // constrain altitude from 0 to 5,000m
     sbufWriteU16BigEndian(dst, altitude);
     sbufWriteU8(dst, gpsSol.numSat);
 }
diff --git a/src/main/telemetry/frsky_hub.c b/src/main/telemetry/frsky_hub.c
index 7bbd05edcd..bc4ef15acc 100644
--- a/src/main/telemetry/frsky_hub.c
+++ b/src/main/telemetry/frsky_hub.c
@@ -269,14 +269,14 @@ static void sendLatLong(int32_t coord[2])
 #if defined(USE_GPS)
 static void sendGpsAltitude(void)
 {
-    uint16_t altitude = gpsSol.llh.alt;
+    int32_t altitudeCm = gpsSol.llh.altCm;
 
     // Send real GPS altitude only if it's reliable (there's a GPS fix)
     if (!STATE(GPS_FIX)) {
-        altitude = 0;
+        altitudeCm = 0;
     }
-    frSkyHubWriteFrame(ID_GPS_ALTIDUTE_BP, altitude);
-    frSkyHubWriteFrame(ID_GPS_ALTIDUTE_AP, 0);
+    frSkyHubWriteFrame(ID_GPS_ALTIDUTE_BP, altitudeCm / 100); // meters: integer part, eg. 123 from 123.45m
+    frSkyHubWriteFrame(ID_GPS_ALTIDUTE_AP, altitudeCm % 100); // meters: fractional part, eg. 45 from 123.45m
 }
 
 static void sendSatalliteSignalQualityAsTemperature2(uint8_t cycleNum)
@@ -340,17 +340,6 @@ static void sendGPSLatLong(void)
 #endif
 #endif
 
-#if defined(USE_BARO) || defined(USE_RANGEFINDER)
-/*
- * Send vertical speed for opentx. ID_VERT_SPEED
- * Unit is cm/s
- */
-static void sendVario(void)
-{
-    frSkyHubWriteFrame(ID_VERT_SPEED, getEstimatedVario());
-}
-#endif
-
 /*
  * Send voltage via ID_VOLT
  *
@@ -535,23 +524,25 @@ void processFrSkyHubTelemetry(timeUs_t currentTimeUs)
         sendAccel();
     }
 
-#if defined(USE_BARO) || defined(USE_RANGEFINDER)
-    if (sensors(SENSOR_BARO | SENSOR_RANGEFINDER)) {
+#if defined(USE_BARO) || defined(USE_RANGEFINDER) || defined(USE_GPS)
+    if (sensors(SENSOR_BARO | SENSOR_RANGEFINDER) | sensors(SENSOR_GPS)) {
         // Sent every 125ms
-        sendVario();
+        // Send vertical speed for opentx. ID_VERT_SPEED
+        // Unit is cm/s
+        frSkyHubWriteFrame(ID_VERT_SPEED, getEstimatedVario());
 
         // Sent every 500ms
         if ((cycleNum % 4) == 0) {
-            int16_t altitude = ABS(getEstimatedAltitude());
+            int32_t altitudeCm = getEstimatedAltitudeCm();
 
             /* Allow 5s to boot correctly othervise send zero to prevent OpenTX
              * sensor lost notifications after warm boot. */
             if (frSkyHubLastCycleTime < DELAY_FOR_BARO_INITIALISATION_US) {
-                altitude = 0;
+                altitudeCm = 0;
             }
 
-            frSkyHubWriteFrame(ID_ALTITUDE_BP, altitude / 100);
-            frSkyHubWriteFrame(ID_ALTITUDE_AP, altitude % 100);
+            frSkyHubWriteFrame(ID_ALTITUDE_BP, altitudeCm / 100); // meters: integer part, eg. 123 from 123.45m
+            frSkyHubWriteFrame(ID_ALTITUDE_AP, altitudeCm % 100); // meters: fractional part, eg. 45 from 123.45m
         }
     }
 #endif
diff --git a/src/main/telemetry/hott.c b/src/main/telemetry/hott.c
index 2aea088980..073e13aa45 100644
--- a/src/main/telemetry/hott.c
+++ b/src/main/telemetry/hott.c
@@ -69,6 +69,7 @@
 #include "build/debug.h"
 
 #include "common/axis.h"
+#include "common/maths.h" 
 #include "common/time.h"
 
 #include "drivers/serial.h"
@@ -236,12 +237,12 @@ void hottPrepareGPSResponse(HOTT_GPS_MSG_t *hottGPSMessage)
     hottGPSMessage->home_distance_L = GPS_distanceToHome & 0x00FF;
     hottGPSMessage->home_distance_H = GPS_distanceToHome >> 8;
 
-    uint16_t altitude = gpsSol.llh.alt;
+    int32_t altitudeM = gpsSol.llh.altCm / 100;
     if (!STATE(GPS_FIX)) {
-        altitude = getEstimatedAltitude();
+        altitudeM = getEstimatedAltitudeCm() / 100;
     }
 
-    const uint16_t hottGpsAltitude = (altitude / 100) + HOTT_GPS_ALTITUDE_OFFSET; // gpsSol.llh.alt in m ; offset = 500 -> O m
+    const uint16_t hottGpsAltitude = constrain(altitudeM + HOTT_GPS_ALTITUDE_OFFSET, 0 , UINT16_MAX); // gpsSol.llh.alt in m ; offset = 500 -> O m
 
     hottGPSMessage->altitude_L = hottGpsAltitude & 0x00FF;
     hottGPSMessage->altitude_H = hottGpsAltitude >> 8;
@@ -296,7 +297,7 @@ static inline void hottEAMUpdateBatteryDrawnCapacity(HOTT_EAM_MSG_t *hottEAMMess
 
 static inline void hottEAMUpdateAltitude(HOTT_EAM_MSG_t *hottEAMMessage)
 {
-    const uint16_t hottEamAltitude = (getEstimatedAltitude() / 100) + HOTT_EAM_OFFSET_HEIGHT;
+    const uint16_t hottEamAltitude = (getEstimatedAltitudeCm() / 100) + HOTT_EAM_OFFSET_HEIGHT;
 
     hottEAMMessage->altitude_L = hottEamAltitude & 0x00FF;
     hottEAMMessage->altitude_H = hottEamAltitude >> 8;
diff --git a/src/main/telemetry/ibus_shared.c b/src/main/telemetry/ibus_shared.c
index 89998f6fe5..38481bc181 100644
--- a/src/main/telemetry/ibus_shared.c
+++ b/src/main/telemetry/ibus_shared.c
@@ -318,7 +318,7 @@ static bool setGPS(uint8_t sensorType, ibusTelemetry_s* value)
                 value->int32 = gpsSol.llh.lon;
                 break;
             case IBUS_SENSOR_TYPE_GPS_ALT:
-                value->int32 = (int32_t)gpsSol.llh.alt;
+                value->int32 = (int32_t)gpsSol.llh.altCm;
                 break;
             case IBUS_SENSOR_TYPE_GROUND_SPEED:
                 value->uint16 = gpsSol.groundSpeed;
diff --git a/src/main/telemetry/jetiexbus.c b/src/main/telemetry/jetiexbus.c
index 3f14cfe7bc..2c28c4a3c9 100644
--- a/src/main/telemetry/jetiexbus.c
+++ b/src/main/telemetry/jetiexbus.c
@@ -236,7 +236,7 @@ int32_t getSensorValue(uint8_t sensor)
         break;
 
     case EX_ALTITUDE:
-        return getEstimatedAltitude();
+        return getEstimatedAltitudeCm() / 100;
         break;
 
     case EX_CAPACITY:
diff --git a/src/main/telemetry/ltm.c b/src/main/telemetry/ltm.c
index 17412e13fb..9209a9c854 100644
--- a/src/main/telemetry/ltm.c
+++ b/src/main/telemetry/ltm.c
@@ -148,9 +148,9 @@ static void ltm_gframe(void)
     ltm_serialise_8((uint8_t)(gpsSol.groundSpeed / 100));
 
 #if defined(USE_BARO) || defined(USE_RANGEFINDER)
-    ltm_alt = (sensors(SENSOR_RANGEFINDER) || sensors(SENSOR_BARO)) ? getEstimatedAltitude() : gpsSol.llh.alt * 100;
+    ltm_alt = (sensors(SENSOR_RANGEFINDER) || sensors(SENSOR_BARO)) ? getEstimatedAltitudeCm() : gpsSol.llh.altCm;
 #else
-    ltm_alt = gpsSol.llh.alt * 100;
+    ltm_alt = gpsSol.llh.altCm;
 #endif
     ltm_serialise_32(ltm_alt);
     ltm_serialise_8((gpsSol.numSat << 2) | gps_fix_type);
diff --git a/src/main/telemetry/mavlink.c b/src/main/telemetry/mavlink.c
index 9b60bdc1c7..4475e2b42b 100644
--- a/src/main/telemetry/mavlink.c
+++ b/src/main/telemetry/mavlink.c
@@ -328,7 +328,7 @@ void mavlinkSendPosition(void)
         // lon Longitude in 1E7 degrees
         gpsSol.llh.lon,
         // alt Altitude in 1E3 meters (millimeters) above MSL
-        gpsSol.llh.alt * 1000,
+        gpsSol.llh.altCm * 10,
         // eph GPS HDOP horizontal dilution of position in cm (m*100). If unknown, set to: 65535
         65535,
         // epv GPS VDOP horizontal dilution of position in cm (m*100). If unknown, set to: 65535
@@ -351,12 +351,12 @@ void mavlinkSendPosition(void)
         // lon Longitude in 1E7 degrees
         gpsSol.llh.lon,
         // alt Altitude in 1E3 meters (millimeters) above MSL
-        gpsSol.llh.alt * 1000,
+        gpsSol.llh.altCm * 10,
         // relative_alt Altitude above ground in meters, expressed as * 1000 (millimeters)
 #if defined(USE_BARO) || defined(USE_RANGEFINDER)
-        (sensors(SENSOR_RANGEFINDER) || sensors(SENSOR_BARO)) ? getEstimatedAltitude() * 10 : gpsSol.llh.alt * 1000,
+        (sensors(SENSOR_RANGEFINDER) || sensors(SENSOR_BARO)) ? getEstimatedAltitudeCm() * 10 : gpsSol.llh.altCm * 10,
 #else
-        gpsSol.llh.alt * 1000,
+        gpsSol.llh.altCm * 10,
 #endif
         // Ground X Speed (Latitude), expressed as m/s * 100
         0,
@@ -423,18 +423,18 @@ void mavlinkSendHUDAndHeartbeat(void)
 #if defined(USE_BARO) || defined(USE_RANGEFINDER)
     if (sensors(SENSOR_RANGEFINDER) || sensors(SENSOR_BARO)) {
         // Baro or sonar generally is a better estimate of altitude than GPS MSL altitude
-        mavAltitude = getEstimatedAltitude() / 100.0;
+        mavAltitude = getEstimatedAltitudeCm() / 100.0;
     }
 #if defined(USE_GPS)
     else if (sensors(SENSOR_GPS)) {
         // No sonar or baro, just display altitude above MLS
-        mavAltitude = gpsSol.llh.alt;
+        mavAltitude = gpsSol.llh.altCm / 100.0;
     }
 #endif
 #elif defined(USE_GPS)
     if (sensors(SENSOR_GPS)) {
         // No sonar or baro, just display altitude above MLS
-        mavAltitude = gpsSol.llh.alt;
+        mavAltitude = gpsSol.llh.altCm / 100.0;
     }
 #endif
 
diff --git a/src/main/telemetry/smartport.c b/src/main/telemetry/smartport.c
index a3b8234558..1b7ceabb87 100644
--- a/src/main/telemetry/smartport.c
+++ b/src/main/telemetry/smartport.c
@@ -635,7 +635,7 @@ void processSmartPortTelemetry(smartPortPayload_t *payload, volatile bool *clear
                 break;
 #endif
             case FSSP_DATAID_ALTITUDE   :
-                smartPortSendPackage(id, getEstimatedAltitude()); // unknown given unit, requested 100 = 1 meter
+                smartPortSendPackage(id, getEstimatedAltitudeCm()); // unknown given unit, requested 100 = 1 meter
                 *clearToSend = false;
                 break;
             case FSSP_DATAID_FUEL       :
@@ -794,7 +794,7 @@ void processSmartPortTelemetry(smartPortPayload_t *payload, volatile bool *clear
                 break;
             case FSSP_DATAID_GPS_ALT    :
                 if (STATE(GPS_FIX)) {
-                    smartPortSendPackage(id, gpsSol.llh.alt * 100); // given in 0.1m , requested in 10 = 1m (should be in mm, probably a bug in opentx, tested on 2.0.1.7)
+                    smartPortSendPackage(id, gpsSol.llh.altCm * 10); // given in 0.01m , requested in 10 = 1m (should be in mm, probably a bug in opentx, tested on 2.0.1.7)
                     *clearToSend = false;
                 }
                 break;
@@ -829,7 +829,7 @@ void handleSmartPortTelemetry(void)
             payload = smartPortDataReceive(c, &clearToSend, serialCheckQueueEmpty, true);
         }
 
-        processSmartPortTelemetry(payload, &clearToSend, &requestTimeout);
+            processSmartPortTelemetry(payload, &clearToSend, &requestTimeout);
     }
 }
 #endif
diff --git a/src/test/unit/osd_unittest.cc b/src/test/unit/osd_unittest.cc
index 2d36e1426d..8df7652730 100644
--- a/src/test/unit/osd_unittest.cc
+++ b/src/test/unit/osd_unittest.cc
@@ -1005,7 +1005,7 @@ extern "C" {
         return simulationMahDrawn;
     }
 
-    int32_t getEstimatedAltitude() {
+    int32_t getEstimatedAltitudeCm() {
         return simulationAltitude;
     }
 
diff --git a/src/test/unit/telemetry_crsf_msp_unittest.cc b/src/test/unit/telemetry_crsf_msp_unittest.cc
index 40374e6209..51a5fbeb36 100644
--- a/src/test/unit/telemetry_crsf_msp_unittest.cc
+++ b/src/test/unit/telemetry_crsf_msp_unittest.cc
@@ -268,6 +268,10 @@ extern "C" {
         return 67;
     }
 
+    int32_t getEstimatedAltitudeCm(void) {
+    	return 0;
+    }
+
     bool feature(uint32_t) {return false;}
 
     bool isAirmodeActive(void) {return true;}
diff --git a/src/test/unit/telemetry_crsf_unittest.cc b/src/test/unit/telemetry_crsf_unittest.cc
index cd9e211069..ed0a29a642 100644
--- a/src/test/unit/telemetry_crsf_unittest.cc
+++ b/src/test/unit/telemetry_crsf_unittest.cc
@@ -124,7 +124,7 @@ TEST(TelemetryCrsfTest, TestGPS)
     gpsSol.llh.lat = 56 * GPS_DEGREES_DIVIDER;
     gpsSol.llh.lon = 163 * GPS_DEGREES_DIVIDER;
     ENABLE_STATE(GPS_FIX);
-    gpsSol.llh.alt = 2345 * 100;              // altitude in cm
+    gpsSol.llh.altCm = 2345 * 100;            // altitude in cm / 100 + 1000m offset, so CRSF value should be 3345
     gpsSol.groundSpeed = 163;                 // speed in 0.1m/s, 16.3 m/s = 58.68 km/h, so CRSF (km/h *10) value is 587
     gpsSol.numSat = 9;
     gpsSol.groundCourse = 1479;     // degrees * 10
@@ -330,6 +330,10 @@ uint8_t calculateBatteryPercentageRemaining(void) {
     return 67;
 }
 
+int32_t getEstimatedAltitudeCm(void) {
+	return gpsSol.llh.altCm;    // function returns cm not m.
+}
+    
 int32_t getMAhDrawn(void){
   return testmAhDrawn;
 }
diff --git a/src/test/unit/telemetry_hott_unittest.cc b/src/test/unit/telemetry_hott_unittest.cc
index 8a00bce26d..08829bc2c5 100644
--- a/src/test/unit/telemetry_hott_unittest.cc
+++ b/src/test/unit/telemetry_hott_unittest.cc
@@ -180,8 +180,8 @@ uint32_t fixedMillis = 0;
 
 baro_t baro;
 
-uint32_t getEstimatedAltitude() { return 0; }
-uint32_t getEstimatedVario() { return 0; }
+int32_t getEstimatedAltitudeCm() { return 0; }
+int16_t getEstimatedVario() { return 0; }
 
 uint32_t millis(void) {
     return fixedMillis;