mirror of https://github.com/ArduPilot/ardupilot
125 lines
4.0 KiB
C++
125 lines
4.0 KiB
C++
#include "SIM_MS5611.h"
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#include <SITL/SITL.h>
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#include <stdio.h>
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using namespace SITL;
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// forward conversion, copied from driver:
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void MS5611::convert_forward(int32_t D1, int32_t D2, float &P_Pa, float &Temp_C)
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{
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// _D1 and _D2 are stored as floats in driver
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const float _D1 = D1;
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const float _D2 = D2;
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float dT;
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float TEMP;
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float OFF;
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float SENS;
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dT = _D2-(((uint32_t)prom[5])<<8);
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TEMP = (dT * prom[6])/8388608;
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OFF = prom[2] * 65536.0f + (prom[4] * dT) / 128;
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SENS = prom[1] * 32768.0f + (prom[3] * dT) / 256;
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TEMP += 2000;
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if (TEMP < 2000) {
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// second order temperature compensation when under 20 degrees C
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float T2 = (dT*dT) / 0x80000000;
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float Aux = sq(TEMP-2000.0);
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float OFF2 = 2.5f*Aux;
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float SENS2 = 1.25f*Aux;
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if (TEMP < -1500) {
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// extra compensation for temperatures below -15C
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OFF2 += 7 * sq(TEMP+1500);
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SENS2 += sq(TEMP+1500) * 11.0*0.5;
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}
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TEMP = TEMP - T2;
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OFF = OFF - OFF2;
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SENS = SENS - SENS2;
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}
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P_Pa = (_D1*SENS/2097152 - OFF)/32768;
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Temp_C = TEMP * 0.01f;
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}
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void MS5611::convert(float P_Pa, float Temp_C, uint32_t &D1, uint32_t &D2)
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{
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const uint8_t Q1 = Qx_coeff[0];
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const uint8_t Q2 = Qx_coeff[1];
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const uint8_t Q3 = Qx_coeff[2];
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const uint8_t Q4 = Qx_coeff[3];
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const uint8_t Q5 = Qx_coeff[4];
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const uint8_t Q6 = Qx_coeff[5];
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const float TEMP = Temp_C * 100;
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// second order temperature compensation when under 20 degrees C
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if (TEMP < 2000) {
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// Solve the quadratic equation for D2 when TEMP < 2000
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D2 = 128 * (2 * int64_t(prom[5]) - sqrt(sq(int64_t(prom[6])) - 131072 * (TEMP - 2000)) + int64_t(prom[6]));
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// Must compute the pressure compensation values using D2
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const float dT = float(D2) - (int64_t(prom[5]) << Q5);
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float TEMP_forward = 2000 + (dT * int64_t(prom[6])) / (1L << Q6);
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float OFF = int64_t(prom[2]) * (1L << Q2) + (int64_t(prom[4]) * dT) / (1L << Q4);
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float SENS = int64_t(prom[1]) * (1L << Q1) + (int64_t(prom[3]) * dT) / (1L << Q3);
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const float Aux = sq(TEMP_forward - 2000);
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float OFF2 = 2.5 * Aux;
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float SENS2 = 1.25 * Aux;
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if (TEMP < -1500) {
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// extra compensation for temperatures below -15C
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OFF2 += 7 * sq(TEMP_forward + 1500);
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SENS2 += sq(TEMP_forward + 1500) * 11.0 * 0.5;
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}
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OFF = OFF - OFF2;
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SENS = SENS - SENS2;
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D1 = ((P_Pa * float(1L << 15) + OFF) * float(1L << 21)) / SENS;
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} else {
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const float dT = (TEMP - 2000) * (1L << Q6) / int64_t(prom[6]);
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const float OFF = int64_t(prom[2]) * (1L << Q2) + (int64_t(prom[4]) * dT) / (1L << Q4);
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const float SENS = int64_t(prom[1]) * (1L << Q1) + (int64_t(prom[3]) * dT) / (1L << Q3);
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D1 = ((P_Pa * float(1L << 15) + OFF) * float(1L << 21)) / SENS;
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D2 = dT + (int64_t(prom[5]) << Q5);
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}
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}
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void MS5611::check_conversion_accuracy(float P_Pa, float Temp_C, uint32_t D1, uint32_t D2)
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{
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float f_P_Pa;
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float f_Temp_C;
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convert_forward(D1, D2, f_P_Pa, f_Temp_C);
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if (fabs(f_P_Pa - P_Pa) > 0.2) {
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AP_HAL::panic("Invalid pressure conversion");
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}
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if (fabs(f_Temp_C - Temp_C) > 0.02) {
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AP_HAL::panic("Invalid temperature conversion");
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}
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}
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void MS5611::get_pressure_temperature_readings(float &P_Pa, float &Temp_C)
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{
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float sigma, delta, theta;
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float sim_alt = AP::sitl()->state.altitude;
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sim_alt += 2 * rand_float();
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AP_Baro::SimpleAtmosphere(sim_alt * 0.001f, sigma, delta, theta);
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P_Pa = SSL_AIR_PRESSURE * delta;
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Temp_C = (SSL_AIR_TEMPERATURE * theta - C_TO_KELVIN) + AP::sitl()->temp_board_offset;
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// TO DO add in temperature adjustment by inheritting from AP_Baro_SITL_Generic?
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// AP_Baro_SITL::temperature_adjustment(P_Pa, Temp_C);
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// TO DO add in wind correction by inheritting from AP_Baro_SITL_Generic?
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// P_Pa += AP_Baro_SITL::wind_pressure_correction(instance);
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}
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