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Diffstat (limited to 'ao-tools/altosui/AltosConvert.java')
| -rw-r--r-- | ao-tools/altosui/AltosConvert.java | 192 |
1 files changed, 0 insertions, 192 deletions
diff --git a/ao-tools/altosui/AltosConvert.java b/ao-tools/altosui/AltosConvert.java deleted file mode 100644 index 8cc1df27..00000000 --- a/ao-tools/altosui/AltosConvert.java +++ /dev/null @@ -1,192 +0,0 @@ -/* - * Copyright © 2010 Keith Packard <keithp@keithp.com> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; version 2 of the License. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. - */ - -/* - * Sensor data conversion functions - */ -package altosui; - -public class AltosConvert { - /* - * Pressure Sensor Model, version 1.1 - * - * written by Holly Grimes - * - * Uses the International Standard Atmosphere as described in - * "A Quick Derivation relating altitude to air pressure" (version 1.03) - * from the Portland State Aerospace Society, except that the atmosphere - * is divided into layers with each layer having a different lapse rate. - * - * Lapse rate data for each layer was obtained from Wikipedia on Sept. 1, 2007 - * at site <http://en.wikipedia.org/wiki/International_Standard_Atmosphere - * - * Height measurements use the local tangent plane. The postive z-direction is up. - * - * All measurements are given in SI units (Kelvin, Pascal, meter, meters/second^2). - * The lapse rate is given in Kelvin/meter, the gas constant for air is given - * in Joules/(kilogram-Kelvin). - */ - - static final double GRAVITATIONAL_ACCELERATION = -9.80665; - static final double AIR_GAS_CONSTANT = 287.053; - static final double NUMBER_OF_LAYERS = 7; - static final double MAXIMUM_ALTITUDE = 84852.0; - static final double MINIMUM_PRESSURE = 0.3734; - static final double LAYER0_BASE_TEMPERATURE = 288.15; - static final double LAYER0_BASE_PRESSURE = 101325; - - /* lapse rate and base altitude for each layer in the atmosphere */ - static final double[] lapse_rate = { - -0.0065, 0.0, 0.001, 0.0028, 0.0, -0.0028, -0.002 - }; - - static final int[] base_altitude = { - 0, 11000, 20000, 32000, 47000, 51000, 71000 - }; - - /* outputs atmospheric pressure associated with the given altitude. - * altitudes are measured with respect to the mean sea level - */ - static double - altitude_to_pressure(double altitude) - { - double base_temperature = LAYER0_BASE_TEMPERATURE; - double base_pressure = LAYER0_BASE_PRESSURE; - - double pressure; - double base; /* base for function to determine pressure */ - double exponent; /* exponent for function to determine pressure */ - int layer_number; /* identifies layer in the atmosphere */ - double delta_z; /* difference between two altitudes */ - - if (altitude > MAXIMUM_ALTITUDE) /* FIX ME: use sensor data to improve model */ - return 0; - - /* calculate the base temperature and pressure for the atmospheric layer - associated with the inputted altitude */ - for(layer_number = 0; layer_number < NUMBER_OF_LAYERS - 1 && altitude > base_altitude[layer_number + 1]; layer_number++) { - delta_z = base_altitude[layer_number + 1] - base_altitude[layer_number]; - if (lapse_rate[layer_number] == 0.0) { - exponent = GRAVITATIONAL_ACCELERATION * delta_z - / AIR_GAS_CONSTANT / base_temperature; - base_pressure *= Math.exp(exponent); - } - else { - base = (lapse_rate[layer_number] * delta_z / base_temperature) + 1.0; - exponent = GRAVITATIONAL_ACCELERATION / - (AIR_GAS_CONSTANT * lapse_rate[layer_number]); - base_pressure *= Math.pow(base, exponent); - } - base_temperature += delta_z * lapse_rate[layer_number]; - } - - /* calculate the pressure at the inputted altitude */ - delta_z = altitude - base_altitude[layer_number]; - if (lapse_rate[layer_number] == 0.0) { - exponent = GRAVITATIONAL_ACCELERATION * delta_z - / AIR_GAS_CONSTANT / base_temperature; - pressure = base_pressure * Math.exp(exponent); - } - else { - base = (lapse_rate[layer_number] * delta_z / base_temperature) + 1.0; - exponent = GRAVITATIONAL_ACCELERATION / - (AIR_GAS_CONSTANT * lapse_rate[layer_number]); - pressure = base_pressure * Math.pow(base, exponent); - } - - return pressure; - } - - -/* outputs the altitude associated with the given pressure. the altitude - returned is measured with respect to the mean sea level */ - static double - pressure_to_altitude(double pressure) - { - - double next_base_temperature = LAYER0_BASE_TEMPERATURE; - double next_base_pressure = LAYER0_BASE_PRESSURE; - - double altitude; - double base_pressure; - double base_temperature; - double base; /* base for function to determine base pressure of next layer */ - double exponent; /* exponent for function to determine base pressure - of next layer */ - double coefficient; - int layer_number; /* identifies layer in the atmosphere */ - int delta_z; /* difference between two altitudes */ - - if (pressure < 0) /* illegal pressure */ - return -1; - if (pressure < MINIMUM_PRESSURE) /* FIX ME: use sensor data to improve model */ - return MAXIMUM_ALTITUDE; - - /* calculate the base temperature and pressure for the atmospheric layer - associated with the inputted pressure. */ - layer_number = -1; - do { - layer_number++; - base_pressure = next_base_pressure; - base_temperature = next_base_temperature; - delta_z = base_altitude[layer_number + 1] - base_altitude[layer_number]; - if (lapse_rate[layer_number] == 0.0) { - exponent = GRAVITATIONAL_ACCELERATION * delta_z - / AIR_GAS_CONSTANT / base_temperature; - next_base_pressure *= Math.exp(exponent); - } - else { - base = (lapse_rate[layer_number] * delta_z / base_temperature) + 1.0; - exponent = GRAVITATIONAL_ACCELERATION / - (AIR_GAS_CONSTANT * lapse_rate[layer_number]); - next_base_pressure *= Math.pow(base, exponent); - } - next_base_temperature += delta_z * lapse_rate[layer_number]; - } - while(layer_number < NUMBER_OF_LAYERS - 1 && pressure < next_base_pressure); - - /* calculate the altitude associated with the inputted pressure */ - if (lapse_rate[layer_number] == 0.0) { - coefficient = (AIR_GAS_CONSTANT / GRAVITATIONAL_ACCELERATION) - * base_temperature; - altitude = base_altitude[layer_number] - + coefficient * Math.log(pressure / base_pressure); - } - else { - base = pressure / base_pressure; - exponent = AIR_GAS_CONSTANT * lapse_rate[layer_number] - / GRAVITATIONAL_ACCELERATION; - coefficient = base_temperature / lapse_rate[layer_number]; - altitude = base_altitude[layer_number] - + coefficient * (Math.pow(base, exponent) - 1); - } - - return altitude; - } - - static double - cc_battery_to_voltage(double battery) - { - return battery / 32767.0 * 5.0; - } - - static double - cc_ignitor_to_voltage(double ignite) - { - return ignite / 32767 * 15.0; - } -} |