AP_InertialSensor: start auto-learning at boot

This makes it easier to setup the params. The ENABLE=2 value only
takes effect at boot

libraries/AP_InertialSensor/AP_InertialSensor.cpp

@@ -862,6 +862,15 @@ AP_InertialSensor::init(uint16_t loop_rate)
         _gyro_harmonic_notch_filter[i].init(_gyro_raw_sample_rates[i], _calculated_harmonic_notch_freq_hz[0],
              _harmonic_notch_filter.bandwidth_hz(), _harmonic_notch_filter.attenuation_dB());
     }
+
+#if HAL_INS_TEMPERATURE_CAL_ENABLE
+    /*
+      see if user has setup for on-boot enable of temperature learning
+     */
+    if (temperature_cal_running()) {
+        tcal_learning = true;
+    }
+#endif
 }
 
 bool AP_InertialSensor::_add_backend(AP_InertialSensor_Backend *backend)
@@ -1566,6 +1575,14 @@ void AP_InertialSensor::update(void)
     _last_update_usec = AP_HAL::micros();
     
     _have_sample = false;
+
+#if HAL_INS_TEMPERATURE_CAL_ENABLE
+    if (tcal_learning && !temperature_cal_running()) {
+        AP_Notify::flags.temp_cal_running = false;
+        AP_Notify::events.temp_cal_saved = 1;
+        GCS_SEND_TEXT(MAV_SEVERITY_WARNING, "TCAL finished all IMUs");
+    }
+#endif
 }
 
 /*

libraries/AP_InertialSensor/AP_InertialSensor.h

@@ -738,8 +738,8 @@ public:
         AP_Enum<Enable> enable;
 
     private:
-        AP_Float temp_min;
         AP_Float temp_max;
+        AP_Float temp_min;
         AP_Vector3f accel_coeff[3];
         AP_Vector3f gyro_coeff[3];
         Vector3f accel_tref;
@@ -763,6 +763,8 @@ private:
     // temperature that last calibration was run at
     AP_Float caltemp_accel[INS_MAX_INSTANCES];
     AP_Float caltemp_gyro[INS_MAX_INSTANCES];
+    bool tcal_learning;
+    int8_t tcal_old_brd_target;
 #endif
 };
 

libraries/AP_InertialSensor/AP_InertialSensor_Backend.cpp

@@ -96,7 +96,9 @@ void AP_InertialSensor_Backend::_rotate_and_correct_accel(uint8_t instance, Vect
     accel.rotate(_imu._accel_orientation[instance]);
 
 #if HAL_INS_TEMPERATURE_CAL_ENABLE
-    _imu.tcal[instance].update_accel_learning(accel, _imu.get_temperature(instance));
+    if (_imu.tcal_learning) {
+        _imu.tcal[instance].update_accel_learning(accel, _imu.get_temperature(instance));
+    }
 #endif
 
     if (!_imu._calibrating_accel && (_imu._acal == nullptr || !_imu._acal->active())) {
@@ -131,7 +133,9 @@ void AP_InertialSensor_Backend::_rotate_and_correct_gyro(uint8_t instance, Vecto
     gyro.rotate(_imu._gyro_orientation[instance]);
 
 #if HAL_INS_TEMPERATURE_CAL_ENABLE
-    _imu.tcal[instance].update_gyro_learning(gyro, _imu.get_temperature(instance));
+    if (_imu.tcal_learning) {
+        _imu.tcal[instance].update_gyro_learning(gyro, _imu.get_temperature(instance));
+    }
 #endif
     
     if (!_imu._calibrating_gyro) {

libraries/AP_InertialSensor/AP_InertialSensor_tempcal.cpp

@@ -26,7 +26,7 @@
 // this scale factor ensures params are easy to work with in GUI parameter editors
 #define SCALE_FACTOR 1.0e6
 #define INV_SCALE_FACTOR 1.0e-6
-#define TEMP_RANGE_MIN 15
+#define TEMP_RANGE_MIN 10
 
 extern const AP_HAL::HAL& hal;
 
@@ -35,9 +35,10 @@ const AP_Param::GroupInfo AP_InertialSensor::TCal::var_info[] = {
 
     // @Param: ENABLE
     // @DisplayName: Enable temperature calibration
-    // @Description: Enable the use of temperature calibration parameters for this IMU
+    // @Description: Enable the use of temperature calibration parameters for this IMU. For automatic learning set to 2 and also set the INS_TCALn_TMAX to the target temperature, then reboot
     // @Values: 0:Disabled,1:Enabled,2:LearnCalibration
     // @User: Advanced
+    // @RebootRequired: True
     AP_GROUPINFO_FLAGS("ENABLE", 1, AP_InertialSensor::TCal, enable,  float(Enable::Disabled), AP_PARAM_FLAG_ENABLE),
 
     // @Param: TMIN
@@ -413,11 +414,6 @@ void AP_InertialSensor::TCal::Learn::finish_calibration(float temperature)
                   instance()+1,
                   tcal.temp_min.get(), tcal.temp_max.get());
     tcal.enable.set_and_save(int8_t(TCal::Enable::Enabled));
-
-    if (!AP::ins().temperature_cal_running()) {
-        AP_Notify::flags.temp_cal_running = false;
-        AP_Notify::events.temp_cal_saved = 1;
-    }
 }
 
 uint8_t AP_InertialSensor::TCal::instance(void) const