Struct StaticSample 

pub struct StaticSample {
    pub imu: ImuSample,
    pub mag: Option<MagField<Body>>,
    pub baro: Option<Altitude>,
    pub velocity: Option<Velocity<Ned>>,
}

One sample from the quasi-static initialization window.

The magnetometer is optional: without it nothing observes the rotation about gravity, ψ₀ of equation (6) stays zero, and the first accepted heading, magnetic, GNSS or course, is what establishes it. A window with none anywhere in it says so: Validity::heading stays false until a heading source accepts one, because sigma_yaw is a prior and would otherwise read as an estimate of a quantity nothing measured.

The barometer is optional in the same way, but less forgivingly: its reference is established by a start and only refined after one (30′), so a window carrying none leaves nothing for a later altitude to be relative to and barometric fusion is refused for the whole flight.

GNSS velocity is the one field a window taken in motion can use, and the only reason this type is not simply an IMU sample plus what stillness needs: see velocity.

Fields

imu: ImuSample

IMU measurement.

mag: Option<MagField<Body>>

Magnetometer measurement, if the vehicle has one.

Averaged over the window to fix ψ₀, the initial heading (equation (6)), and averaged rather than taken from one sample for the reason the barometer and the gyroscope bias are: a single reading carries the sensor’s full noise.

baro: Option<Altitude>

Barometric altitude, if the vehicle has a barometer.

Averaged over the window to fix α₀, the barometer’s reference at the navigation origin (equation (30)). Averaged rather than taken from one sample for the same reason the gyroscope bias is: a single reading carries the sensor’s full noise.

Without it the window fixes no reference, and Eskf::fuse_baro_altitude reads one from the estimate at the first altitude instead. α₀ is refined in flight by (30′), and the scatter of these readings is the variance it starts with, so a window needs two of them.

velocity: Option<Velocity<Ned>>

GNSS velocity in the navigation frame, if the vehicle has a receiver.

Differenced across the window for ā_n, the vehicle’s own acceleration (equation (5′)). At rest that term is zero and equation (5) reads tilt straight off the accelerometer; in motion the accelerometer reads specific force, and ā_n is what separates the two. It is the whole of what a moving window has that a still one does not need.

Attach it to the epoch it arrived on rather than holding it across the IMU epochs that follow, as mag and baro may be held: those are averaged, and an average survives a repeated value, while a difference is dated by the samples carrying it and a held reading dates from before the epoch it sits on. Holding costs up to one GNSS interval of span, in either direction.

Stub. Measured and reported on Coarse::NotStationary; nothing levels with it. Not built: equation (5′), #59.

Trait Implementations

impl Clone for StaticSample

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for StaticSample

impl Debug for StaticSample

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for StaticSample

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for StaticSample

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for StaticSample