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fix(spk): correct de442s parsing and state chaining

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This commit is contained in:
Hanzalah Ravat 2026-04-02 21:59:22 +01:00
parent e8b0afd119
commit 65d2def00a
1 changed files with 26 additions and 10 deletions
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36
src/spk/index.ts
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@ -147,8 +147,8 @@ export class SpkKernel {
const svSunSsb = evaluateSegment(this.buffer, sSunSsb, et, this.le)
const svEmbSsb = evaluateSegment(this.buffer, sEmbSsb, et, this.le)
const svEarthEmb = evaluateSegment(this.buffer, sEarthEmb, et, this.le)
// Earth/SSB = EMB/SSB - Earth/EMB
const earthSsb = subtractSV(svEmbSsb, svEarthEmb)
// Earth/SSB = EMB/SSB + Earth/EMB because the kernel stores 399:3.
const earthSsb = addSV(svEmbSsb, svEarthEmb)
return subtractSV(svSunSsb, earthSsb)
}
}
@ -192,9 +192,11 @@ function parseDafFileRecord(buffer: ArrayBuffer): {
}
const ni = dv.getInt32(12, le)
const fward = dv.getInt32(256, le)
const bward = dv.getInt32(260, le)
const free = dv.getInt32(264, le)
// DAF file record layout stores the forward/backward/free record numbers
// directly after the 60-byte internal file name, not at byte 256.
const fward = dv.getInt32(76, le)
const bward = dv.getInt32(80, le)
const free = dv.getInt32(84, le)
return { nd, ni, fward, bward, free, le }
}
@ -279,9 +281,8 @@ export function evaluateType2(
const intlen = dv.getFloat64(endOffset - 3 * BYTES_PER_DOUBLE, le)
const init = dv.getFloat64(endOffset - 4 * BYTES_PER_DOUBLE, le)
// degree = (rsize - 2) / 3 (Type 2 stores 3 components)
const degree = Math.round((rsize - 2) / 3)
const nCoeffs = degree + 1
// Type 2 record size is RSIZE = 3 * NCOEFF + 2.
const nCoeffs = Math.round((rsize - 2) / 3)
let recIdx = Math.floor((et - init) / intlen)
recIdx = Math.max(0, Math.min(Math.round(N) - 1, recIdx))
@ -320,8 +321,8 @@ export function evaluateType3(
const intlen = dv.getFloat64(endOffset - 3 * BYTES_PER_DOUBLE, le)
const init = dv.getFloat64(endOffset - 4 * BYTES_PER_DOUBLE, le)
const degree = Math.round((rsize - 2) / 6)
const nCoeffs = degree + 1
// Type 3 record size is RSIZE = 6 * NCOEFF + 2.
const nCoeffs = Math.round((rsize - 2) / 6)
let recIdx = Math.floor((et - init) / intlen)
recIdx = Math.max(0, Math.min(Math.round(N) - 1, recIdx))
@ -374,6 +375,21 @@ function subtractSV(a: StateVector, b: StateVector): StateVector {
}
}
function addSV(a: StateVector, b: StateVector): StateVector {
return {
position: [
a.position[0] + b.position[0],
a.position[1] + b.position[1],
a.position[2] + b.position[2],
],
velocity: [
a.velocity[0] + b.velocity[0],
a.velocity[1] + b.velocity[1],
a.velocity[2] + b.velocity[2],
],
}
}
// ─── Leap-second kernel ───────────────────────────────────────────────────────
/**