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AP_Airspeed: added EAS2TAS in airspeed driver

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this keeps the true airspeed ratio in the airspeed driver, which seems
the most logical place
This commit is contained in:
Andrew Tridgell 2013-07-20 11:11:04 +10:00
parent 9bbe6c1967
commit 3c66cb8af1
2 changed files with 19 additions and 8 deletions
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17
libraries/AP_Airspeed/AP_Airspeed.h
View File

@ -26,7 +26,6 @@ private:
const float Q1; // process noise matrix bottom right element
Vector3f state; // state vector
const float DT; // time delta
};
class AP_Airspeed
@ -34,7 +33,8 @@ class AP_Airspeed
public:
// constructor
AP_Airspeed() :
_ets_fd(-1)
_ets_fd(-1),
_EAS2TAS(1.0f)
{
AP_Param::setup_object_defaults(this, var_info);
};
@ -99,8 +99,18 @@ public:
return max(_last_pressure - _offset, 0);
}
// set the apparent to true airspeed ratio
void set_EAS2TAS(float v) {
_EAS2TAS = v;
}
// get the apparent to true airspeed ratio
float get_EAS2TAS(void) const {
return _EAS2TAS;
}
// update airspeed ratio calibration
void update_calibration(Vector3f vground, float EAS2TAS);
void update_calibration(Vector3f vground);
static const struct AP_Param::GroupInfo var_info[];
@ -116,6 +126,7 @@ private:
float _airspeed;
int _ets_fd;
float _last_pressure;
float _EAS2TAS;
Airspeed_Calibration _calibration;
float _last_saved_ratio;

10
libraries/AP_Airspeed/Airspeed_Calibration.cpp
View File

@ -2,7 +2,7 @@
/*
* auto_calibration.cpp - airspeed auto calibration
* Algorithm by Paul Riseborough
* Algorithm by Paul Riseborough
*
*/
@ -102,15 +102,15 @@ float Airspeed_Calibration::update(float airspeed, const Vector3f &vg)
/*
called once a second to do calibration update
*/
void AP_Airspeed::update_calibration(Vector3f vground, float EAS2TAS)
void AP_Airspeed::update_calibration(Vector3f vground)
{
if (!_autocal) {
// auto-calibration not enabled
return;
}
// calculate true airspeed, assuming a ratio of 1.0
float airspeed = sqrtf(get_differential_pressure()) * EAS2TAS;
float ratio = _calibration.update(airspeed, vground);
// calculate true airspeed, assuming a airspeed ratio of 1.0
float true_airspeed = sqrtf(get_differential_pressure()) * _EAS2TAS;
float ratio = _calibration.update(true_airspeed, vground);
if (isnan(ratio) || isinf(ratio)) {
return;
}