Class: NavMath

Defined in: src/sdk/geo/NavMath.ts:10

Navigational mathematics functions.

Constructors

Constructor

new NavMath(): NavMath

Returns

NavMath

Methods

alongTrack()

static alongTrack(start, end, pos): number

Defined in: src/sdk/geo/NavMath.ts:278

Calculates the along-track distance from a starting point to another point along a great-circle track running through the starting point.

Parameters

Parameter	Type	Description
start	LatLonInterface	The start of the great-circle track.
end	LatLonInterface	The end of the great-circle track.
pos	LatLonInterface	The point for which to calculate the along-track distance.

Returns

number

The along-track distance, in nautical miles.

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angleToHeading()

static angleToHeading(angle, turnDirection): number

Defined in: src/sdk/geo/NavMath.ts:234

Converts a degrees north turn circle angle to a degrees north heading.

Parameters

Parameter	Type	Description
angle	number	The turn circle angle to convert.
turnDirection	"left" | "right"	The direction of the turn.

Returns

number

A degrees north heading.

---

bankAngle()

static bankAngle(airspeedTrue, radius): number

Defined in: src/sdk/geo/NavMath.ts:66

Gets the required bank angle for a given true airspeed and turn radius.

Parameters

Parameter	Type	Description
airspeedTrue	number	The true airspeed of the plane, in knots.
radius	number	The airplane turn radius, in meters.

Returns

number

The required bank angle, in degrees.

---

bearingIsBetween()

static bearingIsBetween(bearing, start, end): boolean

Defined in: src/sdk/geo/NavMath.ts:211

Checks if a degrees north bearing is between two other degrees north bearings.

Parameters

Parameter	Type	Description
bearing	number	The bearing in degrees north to check.
start	number	The start bearing in degrees north.
end	number	The end bearing, in degrees north.

Returns

boolean

True if the bearing is between the two provided bearings, false otherwise.

---

calculateArcDistance()

static calculateArcDistance(startBearing, endBearing, radius): number

Defined in: src/sdk/geo/NavMath.ts:134

Calculates the distance along an arc on Earth's surface. The arc begins at the intersection of the great circle passing through the center of a circle of radius radius meters in the direction of 'startBearing', and ends at the intersection of the great circle passing through the center of the circle in the direction of 'endBearing', proceeding clockwise (as viewed from above).

Parameters

Parameter	Type	Description
startBearing	number	The degrees of the start of the arc.
endBearing	number	The degrees of the end of the arc.
radius	number	The radius of the arc, in meters.

Returns

number

The arc distance.

---

circleIntersection()

static circleIntersection(x1, y1, x2, y2, cx, cy, r, sRef): 0 | 1 | 2

Defined in: src/sdk/geo/NavMath.ts:152

Calculates the intersection of a line and a circle.

Parameters

Parameter	Type	Description
x1	number	The start x of the line.
y1	number	The start y of the line.
x2	number	The end x of the line.
y2	number	The end y of the line.
cx	number	The circle center x.
cy	number	The circle center y.
r	number	The radius of the circle.
sRef	CircleIntersection	The reference to the solution object to write the solution to.

Returns

0 | 1 | 2

The number of solutions (0, 1 or 2).

---

clamp()

static clamp(val, min, max): number

Defined in: src/sdk/geo/NavMath.ts:22

Clamps a value to a min and max.

Parameters

Parameter	Type	Description
val	number	The value to clamp.
min	number	The minimum value to clamp to.
max	number	The maximum value to clamp to.

Returns

number

The clamped value.

---

crossTrack()

static crossTrack(start, end, pos): number

Defined in: src/sdk/geo/NavMath.ts:260

Calculates the cross track deviation from the provided leg fixes.

Parameters

Parameter	Type	Description
start	LatLonInterface	The location of the starting fix of the leg.
end	LatLonInterface	The location of the ending fix of the leg.
pos	LatLonInterface	The current plane location coordinates.

Returns

number

The amount of cross track deviation, in nautical miles.

---

crossTrackArc()

static crossTrackArc(center, radius, pos): number

Defined in: src/sdk/geo/NavMath.ts:367

Gets the cross track distance for a given arc.

Parameters

Parameter	Type	Description
center	LatLonInterface	The center of the arc.
radius	number	The radius of the arc, in meters.
pos	LatLonInterface	The current plane position.

Returns

number

The cross track distance, in NM.

---

degreesNorthToPolar()

static degreesNorthToPolar(degrees): number

Defined in: src/sdk/geo/NavMath.ts:120

Converts degrees north to polar radians.

Parameters

Parameter	Type	Description
degrees	number	The degrees to convert.

Returns

number

The angle radians, in polar.

---

desiredTrack()

static desiredTrack(start, end, pos): number

Defined in: src/sdk/geo/NavMath.ts:296

Calculates the desired track from the provided leg fixes.

Parameters

Parameter	Type	Description
start	LatLonInterface	The location of the starting fix of the leg.
end	LatLonInterface	The location of the ending fix of the leg.
pos	LatLonInterface	The current plane location coordinates.

Returns

number

The desired track, in degrees true.

---

desiredTrackArc()

static desiredTrackArc(center, turnDirection, pos): number

Defined in: src/sdk/geo/NavMath.ts:313

Gets the desired track for a given arc.

Parameters

Parameter	Type	Description
center	LatLonInterface	The center of the arc.
turnDirection	"left" | "right"	The direction of the turn.
pos	LatLonInterface	The current plane position.

Returns

number

The desired track.

---

diffAngle()

static diffAngle(a, b): number

Defined in: src/sdk/geo/NavMath.ts:377

Gets the total difference in degrees between two angles.

Parameters

Parameter	Type	Description
a	number	The first angle.
b	number	The second angle.

Returns

number

The difference between the two angles, in degrees, in range -180°...+180°.

---

getTurnDirection()

static getTurnDirection(startCourse, endCourse): "left" | "right"

Defined in: src/sdk/geo/NavMath.ts:102

Get the turn direction for a given course change.

Parameters

Parameter	Type	Description
startCourse	number	The start course.
endCourse	number	The end course.

Returns

"left" | "right"

The turn direction for the course change.

---

headingToAngle()

static headingToAngle(heading, turnDirection): number

Defined in: src/sdk/geo/NavMath.ts:224

Converts a degrees north heading to a degrees north turn circle angle.

Parameters

Parameter	Type	Description
heading	number	The heading to convert.
turnDirection	"left" | "right"	The direction of the turn.

Returns

number

A degrees north turn circle angle.

---

headingToGroundTrack()

static headingToGroundTrack(heading, tas, windDirection, windSpeed): number

Defined in: src/sdk/geo/NavMath.ts:81

Calculates the expected ground track of an airplane for a given heading, true airspeed, and wind conditions.

Parameters

Parameter	Type	Description
heading	number	The airplane's heading, in degrees.
tas	number	The airplane's true airspeed, in the same units as windSpeed.
windDirection	number	The wind direction, in degrees. Wind direction is defined as the heading from which the wind is blowing.
windSpeed	number	The wind speed, in the same units as tas.

Returns

number

The expected ground track of an airplane, in degrees, for the specified heading, true airspeed, and wind conditions. If the specified parameters result in an expected ground speed of zero, then NaN is returned.

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napierSide()

static napierSide(b, c, beta, gamma): number

Defined in: src/sdk/geo/NavMath.ts:396

Finds side a given sides b, c, and angles beta, gamma.

Parameters

Parameter	Type	Description
b	number	The length of side b, as a trigonometric ratio.
c	number	The length of side c, as a trigonometric ratio.
beta	number	The angle, in radians, of the opposite of side b.
gamma	number	The angle, in radians, of the opposite of side c

Returns

number

The length of side a, as a trigonometric ratio.

---

normal()

static normal(course, turnDirection, outVector): void

Defined in: src/sdk/geo/NavMath.ts:407

Calculates a normal vector to a provided course in degrees north.

Parameters

Parameter	Type	Description
course	number	The course in degrees north.
turnDirection	"left" | "right"	The direction of the turn to orient the normal.
outVector	Float64Array	The normal vector for the provided course.

Returns

void

---

normalizeHeading()

static normalizeHeading(heading): number

Defined in: src/sdk/geo/NavMath.ts:31

Normalizes a heading to a 0-360 range.

Parameters

Parameter	Type	Description
heading	number	The heading to normalize.

Returns

number

The normalized heading.

---

northAngle()

static northAngle(cx, cy, x, y): number

Defined in: src/sdk/geo/NavMath.ts:200

Gets the degrees north that a point lies on a circle.

Parameters

Parameter	Type	Description
cx	number	The x point of the center of the circle.
cy	number	The y point of the center of the circle.
x	number	The x point to get the bearing for.
y	number	The y point to get the bearing for.

Returns

number

The angle in degrees north that the point is relative to the center.

---

percentAlongTrackArc()

static percentAlongTrackArc(start, end, center, turnDirection, pos): number

Defined in: src/sdk/geo/NavMath.ts:328

Gets the percentage along the arc path that the plane currently is.

Parameters

Parameter	Type	Description
start	number	The start of the arc, in degrees north.
end	number	The end of the arc, in degrees north.
center	LatLonInterface	The center location of the arc.
turnDirection	"left" | "right"	The direction of the turn.
pos	LatLonInterface	The current plane position.

Returns

number

The percentage along the arc the plane is.

---

polarToDegreesNorth()

static polarToDegreesNorth(radians): number

Defined in: src/sdk/geo/NavMath.ts:111

Converts polar radians to degrees north.

Parameters

Parameter	Type	Description
radians	number	The radians to convert.

Returns

number

The angle, in degrees north.

---

positionAlongArc()

static positionAlongArc(start, center, radius, turnDirection, distance, out): GeoPoint

Defined in: src/sdk/geo/NavMath.ts:350

Gets a position given an arc and a distance from the arc start.

Parameters

Parameter	Type	Description
start	number	The start bearing of the arc.
center	GeoPoint	The center of the arc.
radius	number	The radius of the arc.
turnDirection	"left" | "right"	The turn direction for the arc.
distance	number	The distance along the arc to get the position for.
out	GeoPoint	The position to write to.

Returns

GeoPoint

The position along the arc that was written to.

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reciprocateHeading()

static reciprocateHeading(heading): number

Defined in: src/sdk/geo/NavMath.ts:45

Inverts a heading value by adding 180 and normalizing.

Parameters

Parameter	Type	Description
heading	number	The heading to invert/reciprocate.

Returns

number

The inverted/reciprocated heading.

---

turnRadius()

static turnRadius(airspeedTrue, bankAngle): number

Defined in: src/sdk/geo/NavMath.ts:55

Gets the turn radius for a given true airspeed.

Parameters

Parameter	Type	Description
airspeedTrue	number	The true airspeed of the plane, in knots.
bankAngle	number	The bank angle of the plane, in degrees.

Returns

number

The airplane turn radius, in meters.

---

windCorrectionAngle()

static windCorrectionAngle(course, airspeedTrue, windDirection, windSpeed): number

Defined in: src/sdk/geo/NavMath.ts:246

Calculates the wind correction angle.

Parameters

Parameter	Type	Description
course	number	The current plane true course.
airspeedTrue	number	The current plane true airspeed.
windDirection	number	The direction of the wind, in degrees true.
windSpeed	number	The current speed of the wind.

Returns

number

The calculated wind correction angle.