ArduCopter: Fix typos

ArduCopter/ReleaseNotes.txt

@@ -178,7 +178,7 @@ Changes from 3.3-rc3
     b) H_COLYAW param can be float 
 8) Small Improvements / Bug Fixes:
     a) reduced spline overshoot after very long track followed by very short track
-    b) log entire mission to dataflash whenver it's uploaded
+    b) log entire mission to dataflash whenever it's uploaded
     c) altitude reported if vehicle takes off before GPS lock
     d) high speed logging of IMU
     e) STOP flight mode renamed to BRAKE and aux switch option added
@@ -332,7 +332,7 @@ Changes from 3.2-rc7
 3) sensor health flags sent to GCS only after initialisation to remove false alerts 
 4) suppress bad terrain data alerts
 5) Bug Fix:
-    a)PX4 dataflash RAM useage reduced to 8k so it works again  
+    a)PX4 dataflash RAM usage reduced to 8k so it works again  
 ------------------------------------------------------------------
 ArduCopter 3.2-rc7 04-Sep-2014
 Changes from 3.2-rc6
@@ -694,7 +694,7 @@ Improvements over 3.0.0-rc3
 6) RTL returns to initial yaw heading before descending
 7) safe features:
     i) check for gps lock when entering failsafe
-    ii) pre-arm check for mag field lenght
+    ii) pre-arm check for mag field length
     iii) pre-arm check for board voltage between 4.5v ~ 5.8V
     iv) beep twice during arming
     v) GPS failsafe enabled by default (will LAND if loses GPS in Loiter, AUTO, Guided modes)
@@ -794,7 +794,7 @@ Improvements over 2.9-rc3:
 ArduCopter 2.9-rc3 11-Jan-2013
 Improvements over 2.9-rc2:
 1) alt hold with sonar improvements - now on by default (Leonard/Randy)
-2) performance and memory useage improvements (Tridge/Randy)
+2) performance and memory usage improvements (Tridge/Randy)
 3) increase APM1 baro pressure read from 5hz to 8.3hz to improve alt hold (Randy)
 4) bug fix: altitude error reported to GCS (Randy)
 5) limit inertial nav's max accel offset correction to 100cm/s/s to speed up recovery after hard impacts (Randy)_

ArduCopter/config.h

@@ -469,7 +469,7 @@
 #endif
 
 #ifndef RTL_LOITER_TIME
- # define RTL_LOITER_TIME           5000    // Time (in milliseconds) to loiter above home before begining final descent
+ # define RTL_LOITER_TIME           5000    // Time (in milliseconds) to loiter above home before beginning final descent
 #endif
 
 // AUTO Mode

ArduCopter/events.cpp

@@ -103,7 +103,7 @@ void Copter::failsafe_gcs_check()
         return;
     }
 
-    // GCS failsafe event has occured
+    // GCS failsafe event has occurred
     // update state, log to dataflash
     set_failsafe_gcs(true);
     Log_Write_Error(ERROR_SUBSYSTEM_FAILSAFE_GCS, ERROR_CODE_FAILSAFE_OCCURRED);

ArduCopter/flight_mode.cpp

@@ -9,7 +9,7 @@
 
 // set_mode - change flight mode and perform any necessary initialisation
 // optional force parameter used to force the flight mode change (used only first time mode is set)
-// returns true if mode was succesfully set
+// returns true if mode was successfully set
 // ACRO, STABILIZE, ALTHOLD, LAND, DRIFT and SPORT can always be set successfully but the return state of other flight modes should be checked and the caller should deal with failures appropriately
 bool Copter::set_mode(control_mode_t mode, mode_reason_t reason)
 {

ArduCopter/radio.cpp

@@ -151,7 +151,7 @@ void Copter::set_throttle_and_failsafe(uint16_t throttle_pwm)
         }
 
         // check for 3 low throttle values
-        // Note: we do not pass through the low throttle until 3 low throttle values are recieved
+        // Note: we do not pass through the low throttle until 3 low throttle values are received
         failsafe.radio_counter++;
         if( failsafe.radio_counter >= FS_COUNTER ) {
             failsafe.radio_counter = FS_COUNTER;  // check to ensure we don't overflow the counter

ArduCopter/system.cpp

@@ -312,7 +312,7 @@ void Copter::startup_INS_ground()
     ahrs.reset();
 }
 
-// calibrate gyros - returns true if succesfully calibrated
+// calibrate gyros - returns true if successfully calibrated
 bool Copter::calibrate_gyros()
 {
     // gyro offset calibration