micro-bit-led-compass/independent_logic/src/tilt_compensation.rs
2023-10-28 23:02:22 -05:00

54 lines
1.6 KiB
Rust

use libm::{atan2f, atanf, cosf, sinf};
#[derive(Debug)]
pub struct Attitude {
pub pitch: f32,
pub roll: f32,
}
#[derive(Debug)]
pub struct NedMeasurement {
pub x: f32,
pub y: f32,
pub z: f32,
}
//theta=0 at north, pi/-pi at south, pi/2 at east, and -pi/2 at west (desired)
//theta=0 at south, pi/-pi at north, pi/2 at east, and -pi/2 at west (current)
pub struct Heading(pub f32);
pub fn calc_attitude(measurement: &NedMeasurement) -> Attitude {
//based off of: https://www.nxp.com/docs/en/application-note/AN4248.pdf
let roll = atan2f(measurement.y, measurement.z);
let pitch = atanf(-measurement.x / (measurement.y * sinf(roll) + measurement.z * cosf(roll)));
Attitude { pitch, roll }
// Attitude { pitch: 0.0, roll: 0.0 }
}
pub fn calc_tilt_calibrated_measurement(
mag_measurement: NedMeasurement,
attitde: &Attitude,
) -> NedMeasurement {
//based off of: https://www.nxp.com/docs/en/application-note/AN4248.pdf
let corrected_mag_y =
mag_measurement.z * sinf(attitde.roll) - mag_measurement.y * cosf(attitde.roll);
let corrected_mag_x = mag_measurement.x * cosf(attitde.pitch)
+ mag_measurement.y * sinf(attitde.pitch) * sinf(attitde.roll)
+ mag_measurement.z * sinf(attitde.pitch) * cosf(attitde.roll);
NedMeasurement {
x: corrected_mag_x,
y: corrected_mag_y,
z: 0.0,
}
}
//0 is the top sector and positive is clockwise, negative is counterclockwise.
pub fn heading_from_measurement(measurement: NedMeasurement) -> Heading {
Heading(atan2f(-measurement.y, measurement.x))
}
//I have no freaking clue how to test this...