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Code Issues Releases Activity

Added a moving-average-filter to the pressure reading, and increased BMP085 oversampling from 2 to 3

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git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@2336 ebee16cc-31ac-478f-84a7-5cbb03baadba
This commit is contained in:
pip 2011-01-05 11:26:47 +00:00 committed by pip
parent 6eae425644
commit cb8e9ef07b
2 changed files with 33 additions and 3 deletions
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33
flight/OpenPilot/Modules/Altitude/altitude.c
View File

@ -39,6 +39,8 @@
#include "openpilot.h"
#include "baroaltitude.h" // object that will be updated by the module
#define ALT_PRES_MAF // uncommment this to not use the pressure moving-average-filter
// Private constants
#define STACK_SIZE configMINIMAL_STACK_SIZE
#define TASK_PRIORITY (tskIDLE_PRIORITY+3)
@ -49,6 +51,13 @@
// Private variables
static xTaskHandle taskHandle;
// moving average filter variables
#ifdef ALT_PRES_MAF
#define alt_maf_size 4
static int32_t alt_maf_buf[alt_maf_size];
static int32_t alt_maf_out = 0;
#endif
// Private functions
static void altitudeTask(void *parameters);
@ -61,6 +70,11 @@ int32_t AltitudeInitialize()
// Start main task
xTaskCreate(altitudeTask, (signed char *)"Altitude", STACK_SIZE, NULL, TASK_PRIORITY, &taskHandle);
// clear the moving average filter
for (int i = 0; i < alt_maf_size; i++)
alt_maf_buf[i] = 0;
alt_maf_out = 0;
return 0;
}
@ -89,9 +103,24 @@ static void altitudeTask(void *parameters)
PIOS_BMP085_StartADC(PressureConv);
xSemaphoreTake(PIOS_BMP085_EOC, portMAX_DELAY);
// read pressure
PIOS_BMP085_ReadADC();
// Convert from Pa to kPa
data.Pressure = PIOS_BMP085_GetPressure() / 1000.0;
int32_t pressure = PIOS_BMP085_GetPressure();
#ifdef ALT_PRES_MAF
// moving average filter the pressure
alt_maf_out -= alt_maf_buf[0];
for (int i = 0; i < alt_maf_size - 1; i++)
alt_maf_buf[i] = alt_maf_buf[i + 1];
alt_maf_buf[alt_maf_size - 1] = pressure;
alt_maf_out += pressure;
// Convert from Pa to kPa
data.Pressure = alt_maf_out / (1000.0f * alt_maf_size);
#else
// Convert from Pa to kPa
data.Pressure = pressure / 1000.0f;
#endif
// Compute the current altitude (all pressures in kPa)
data.Altitude = 44330.0 * (1.0 - powf((data.Pressure / (BMP085_P0 / 1000.0)), (1.0 / 5.255)));

3
flight/PiOS/Boards/STM3210E_OP.h
View File

@ -117,7 +117,8 @@ TIM8 | Servo 5 | Servo 6 | Servo 7 | Servo 8
#define PIOS_BMP085_EOC_EXTI_LINE EXTI_Line15
#define PIOS_BMP085_EOC_IRQn EXTI15_10_IRQn
#define PIOS_BMP085_EOC_PRIO PIOS_IRQ_PRIO_HIGH
#define PIOS_BMP085_OVERSAMPLING 2
//#define PIOS_BMP085_OVERSAMPLING 2
#define PIOS_BMP085_OVERSAMPLING 3
//-------------------------
// USART