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linter first pass #7

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14 changes: 5 additions & 9 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -12,19 +12,15 @@ I decided to port the SGP4 library to GoLang as one of my first projects with th
#### Constants

```go
const DEG2RAD float64 = math.Pi / 180.0
const deg2rad float64 = math.Pi / 180.0
```

```go
const RAD2DEG float64 = 180.0 / math.Pi
const twopi float64 = math.Pi * 2.0
```

```go
const TWOPI float64 = math.Pi * 2.0
```

```go
const XPDOTP float64 = 1440.0 / (2.0 * math.Pi)
const xPDOTP float64 = 1440.0 / (2.0 * math.Pi)
```

#### func ECIToLLA
Expand Down Expand Up @@ -57,10 +53,10 @@ func Propagate(sat Satellite, year int, month int, day, hours, minutes, seconds
```
Calculates position and velocity vectors for given time

#### func ThetaG_JD
#### func ThetaGFromJulianDate

```go
func ThetaG_JD(jday float64) (ret float64)
func ThetaGFromJulianDate(jday float64) (ret float64)
```
Calculate GMST from Julian date. Reference: The 1992 Astronomical Almanac, page
B6.
Expand Down
40 changes: 20 additions & 20 deletions conversions.go
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Expand Up @@ -20,7 +20,7 @@ func days2mdhms(year int64, epochDays float64) (mon, day, hr, min, sec float64)

for dayofyr > inttemp+float64(lmonth[int(i-1)]) && i < 22 {
inttemp = inttemp + float64(lmonth[int(i-1)])
i += 1
i++
}

mon = i
Expand All @@ -37,7 +37,7 @@ func days2mdhms(year int64, epochDays float64) (mon, day, hr, min, sec float64)
return
}

// Calc julian date given year, month, day, hour, minute and second
// JDay calc julian date given year, month, day, hour, minute and second
// the julian date is defined by each elapsed day since noon, jan 1, 4713 bc.
func JDay(year, mon, day, hr, min, sec int) float64 {
return (367.0*float64(year) - math.Floor((7*(float64(year)+math.Floor((float64(mon)+9)/12.0)))*0.25) + math.Floor(275*float64(mon)/9.0) + float64(day) + 1721013.5 + ((float64(sec)/60.0+float64(min))/60.0+float64(hr))/24.0)
Expand All @@ -47,22 +47,22 @@ func JDay(year, mon, day, hr, min, sec int) float64 {
func gstime(jdut1 float64) (temp float64) {
tut1 := (jdut1 - 2451545.0) / 36525.0
temp = -6.2e-6*tut1*tut1*tut1 + 0.093104*tut1*tut1 + (876600.0*3600+8640184.812866)*tut1 + 67310.54841
temp = math.Mod((temp * DEG2RAD / 240.0), TWOPI)
temp = math.Mod((temp * deg2rad / 240.0), twoPi)

if temp < 0.0 {
temp += TWOPI
temp += twoPi
}

return
}

// Calc GST given year, month, day, hour, minute and second
// GSTimeFromDate calc GST given year, month, day, hour, minute and second
func GSTimeFromDate(year, mon, day, hr, min, sec int) float64 {
jDay := JDay(year, mon, day, hr, min, sec)
return gstime(jDay)
}

// Convert Earth Centered Inertial coordinated into equivalent latitude, longitude, altitude and velocity.
// ECIToLLA converts Earth Centered Inertial coordinated into equivalent latitude, longitude, altitude and velocity.
// Reference: http://celestrak.com/columns/v02n03/
func ECIToLLA(eciCoords Vector3, gmst float64) (altitude, velocity float64, ret LatLong) {
a := 6378.137 // Semi-major Axis
Expand Down Expand Up @@ -95,7 +95,7 @@ func ECIToLLA(eciCoords Vector3, gmst float64) (altitude, velocity float64, ret
return
}

// Convert LatLong in radians to LatLong in degrees
// LatLongDeg converts LatLong in radians to LatLong in degrees
func LatLongDeg(rad LatLong) (deg LatLong) {
deg.Longitude = math.Mod(rad.Longitude/math.Pi*180, 360)
if deg.Longitude > 180 {
Expand All @@ -111,9 +111,9 @@ func LatLongDeg(rad LatLong) (deg LatLong) {
return
}

// Calculate GMST from Julian date.
// ThetaGFromJulianDate calculates GMST from Julian date.
// Reference: The 1992 Astronomical Almanac, page B6.
func ThetaG_JD(jday float64) (ret float64) {
func ThetaGFromJulianDate(jday float64) (ret float64) {
_, UT := math.Modf(jday + 0.5)
jday = jday - UT
TU := (jday - 2451545.0) / 36525.0
Expand All @@ -123,19 +123,19 @@ func ThetaG_JD(jday float64) (ret float64) {
return
}

// Convert latitude, longitude and altitude into equivalent Earth Centered Intertial coordinates
// LLAToECI converts latitude, longitude and altitude into equivalent Earth Centered Intertial coordinates
// Reference: The 1992 Astronomical Almanac, page K11.
func LLAToECI(obsCoords LatLong, alt, jday float64) (eciObs Vector3) {
re := 6378.137
theta := math.Mod(ThetaG_JD(jday)+obsCoords.Longitude, TWOPI)
theta := math.Mod(ThetaGFromJulianDate(jday)+obsCoords.Longitude, twoPi)
r := (re + alt) * math.Cos(obsCoords.Latitude)
eciObs.X = r * math.Cos(theta)
eciObs.Y = r * math.Sin(theta)
eciObs.Z = (re + alt) * math.Sin(obsCoords.Latitude)
return
}

// Convert Earth Centered Intertial coordinates into Earth Cenetered Earth Final coordinates
// ECIToECEF converts Earth Centered Intertial coordinates into Earth Cenetered Earth Final coordinates
// Reference: http://ccar.colorado.edu/ASEN5070/handouts/coordsys.doc
func ECIToECEF(eciCoords Vector3, gmst float64) (ecfCoords Vector3) {
ecfCoords.X = eciCoords.X*math.Cos(gmst) + eciCoords.Y*math.Sin(gmst)
Expand All @@ -144,30 +144,30 @@ func ECIToECEF(eciCoords Vector3, gmst float64) (ecfCoords Vector3) {
return
}

// Calculate look angles for given satellite position and observer position
// ECIToLookAngles calculates look angles for given satellite position and observer position
// obsAlt in km
// Reference: http://celestrak.com/columns/v02n02/
func ECIToLookAngles(eciSat Vector3, obsCoords LatLong, obsAlt, jday float64) (lookAngles LookAngles) {
theta := math.Mod(ThetaG_JD(jday)+obsCoords.Longitude, 2*math.Pi)
theta := math.Mod(ThetaGFromJulianDate(jday)+obsCoords.Longitude, 2*math.Pi)
obsPos := LLAToECI(obsCoords, obsAlt, jday)

rx := eciSat.X - obsPos.X
ry := eciSat.Y - obsPos.Y
rz := eciSat.Z - obsPos.Z

top_s := math.Sin(obsCoords.Latitude)*math.Cos(theta)*rx + math.Sin(obsCoords.Latitude)*math.Sin(theta)*ry - math.Cos(obsCoords.Latitude)*rz
top_e := -math.Sin(theta)*rx + math.Cos(theta)*ry
top_z := math.Cos(obsCoords.Latitude)*math.Cos(theta)*rx + math.Cos(obsCoords.Latitude)*math.Sin(theta)*ry + math.Sin(obsCoords.Latitude)*rz
topS := math.Sin(obsCoords.Latitude)*math.Cos(theta)*rx + math.Sin(obsCoords.Latitude)*math.Sin(theta)*ry - math.Cos(obsCoords.Latitude)*rz
topE := -math.Sin(theta)*rx + math.Cos(theta)*ry
topZ := math.Cos(obsCoords.Latitude)*math.Cos(theta)*rx + math.Cos(obsCoords.Latitude)*math.Sin(theta)*ry + math.Sin(obsCoords.Latitude)*rz

lookAngles.Az = math.Atan(-top_e / top_s)
if top_s > 0 {
lookAngles.Az = math.Atan(-topE / topS)
if topS > 0 {
lookAngles.Az = lookAngles.Az + math.Pi
}
if lookAngles.Az < 0 {
lookAngles.Az = lookAngles.Az + 2*math.Pi
}
lookAngles.Rg = math.Sqrt(rx*rx + ry*ry + rz*rz)
lookAngles.El = math.Asin(top_z / lookAngles.Rg)
lookAngles.El = math.Asin(topZ / lookAngles.Rg)

return
}
33 changes: 16 additions & 17 deletions dspace.go
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Expand Up @@ -4,12 +4,12 @@ import (
"math"
)

// A struct returned from the dsinit function
// DeepSpaceInitResult a struct returned from the dsinit function
type DeepSpaceInitResult struct {
em, argpm, inclm, mm, nm, nodem, irez, atime, d2201, d2211, d3210, d3222, d4410, d4422, d5220, d5232, d5421, d5433, dedt, didt, dmdt, dndt, dnodt, domdt, del1, del2, del3, xfact, xlamo, xli, xni float64
}

// A struct returned from the dspace function
// DeepSpaceResult a struct returned from the dspace function
type DeepSpaceResult struct {
atime, em, argpm, inclm, xli, mm, xni, nodem, dndt, nm float64
}
Expand All @@ -34,7 +34,6 @@ func dsinit(whichconst GravConst, cosim, emsq, argpo, s1, s2, s3, s4, s5, sinim,

xke := whichconst.xke

irez = 0
if 0.0034906585 < nm && nm < 0.0052359877 {
irez = 1
}
Expand Down Expand Up @@ -74,7 +73,7 @@ func dsinit(whichconst GravConst, cosim, emsq, argpo, s1, s2, s3, s4, s5, sinim,
}

dndt := 0.0
theta = math.Mod(gsto+tc*rptim, TWOPI)
theta = math.Mod(gsto+tc*rptim, twoPi)
em = em + dedt*t
inclm = inclm + didt*t
argpm = argpm + domdt*t
Expand Down Expand Up @@ -154,7 +153,7 @@ func dsinit(whichconst GravConst, cosim, emsq, argpo, s1, s2, s3, s4, s5, sinim,
temp = 2.0 * temp1 * root54
d5421 = temp * f542 * g521
d5433 = temp * f543 * g533
xlamo = math.Mod(mo+nodeo+nodeo-theta-theta, TWOPI)
xlamo = math.Mod(mo+nodeo+nodeo-theta-theta, twoPi)
xfact = mdot + dmdt + 2.0*(nodedot+dnodt-rptim) - no
em = emo
emsq = emsqo
Expand All @@ -171,7 +170,7 @@ func dsinit(whichconst GravConst, cosim, emsq, argpo, s1, s2, s3, s4, s5, sinim,
del2 = 2.0 * del1 * f220 * g200 * q22
del3 = 3.0 * del1 * f330 * g300 * q33 * aonv
del1 = del1 * f311 * g310 * q31 * aonv
xlamo = math.Mod(mo+nodeo+argpo-theta, TWOPI)
xlamo = math.Mod(mo+nodeo+argpo-theta, twoPi)
xfact = mdot + xpidot - rptim + dmdt + domdt + dnodt - no
}
xli = xlamo
Expand Down Expand Up @@ -233,7 +232,7 @@ func dspace(irez, d2201, d2211, d3210, d3222, d4410, d4422, d5220, d5232, d5421,
step2 := 259200.0

dndt := 0.0
theta = math.Mod((gsto + tc*rptim), TWOPI)
theta = math.Mod((gsto + tc*rptim), twoPi)
em = em + dedt*t

inclm = inclm + didt*t
Expand Down Expand Up @@ -314,7 +313,7 @@ func dspace(irez, d2201, d2211, d3210, d3222, d4410, d4422, d5220, d5232, d5421,
return
}

// A struct returned from the dpper function
// DpperResult a struct returned from the dpper function
type DpperResult struct {
ep, inclp, nodep, argpp, mp float64
}
Expand Down Expand Up @@ -423,21 +422,21 @@ func dpper(satrec *Satellite, inclo float64, init string, ep, inclp, nodep, argp

alfdp = alfdp + dalf
betdp = betdp + dbet
nodep = math.Mod(nodep, TWOPI)
nodep = math.Mod(nodep, twoPi)
if nodep < 0.0 && opsmode == "a" {
nodep = nodep + TWOPI
nodep = nodep + twoPi
}
xls := mp + argpp + pl + pgh + (cosip-pinc*sinip)*nodep
xnoh := nodep
nodep = math.Atan2(alfdp, betdp)
if nodep < 0.0 && opsmode == "a" {
nodep = nodep + TWOPI
nodep = nodep + twoPi
}
if math.Abs(xnoh-nodep) > math.Pi {
if nodep < xnoh {
nodep = nodep + TWOPI
nodep = nodep + twoPi
} else {
nodep = nodep - TWOPI
nodep = nodep - twoPi
}
}
mp += pl
Expand All @@ -454,7 +453,7 @@ func dpper(satrec *Satellite, inclo float64, init string, ep, inclp, nodep, argp
return
}

// A struct returned from the dscom function
// DSComResults a struct returned from the dscom function
type DSComResults struct {
snodm, cnodm, sinim, cosim, sinomm, cosomm, day, e3, ee2, em, emsq, gam, peo, pgho, pho, pinco, plo, rtemsq, se2, se3, sgh2, sgh3, sgh4, sh2, sh3, si2, si3, sl2, sl3, sl4, s1, s2, s3, s4, s5, s6, s7, ss1, ss2, ss3, ss4, ss5, ss6, ss7, sz1, sz2, sz3, sz11, sz12, sz13, sz21, sz22, sz23, sz31, sz32, sz33, xgh2, xgh3, xgh4, xh2, xh3, xi2, xi3, xl2, xl3, xl4, nm, z1, z2, z3, z11, z12, z13, z21, z22, z23, z31, z32, z33, zmol, zmos float64
}
Expand Down Expand Up @@ -490,7 +489,7 @@ func dscom(epoch, ep, argpp, tc, inclp, nodep, np, e3, ee2, peo, pgho, pho, pinc
pgho = 0.0
pho = 0.0
day := epoch + 18261.5 + tc/1440.0
xnodce = math.Mod(4.5236020-9.2422029e-4*day, TWOPI)
xnodce = math.Mod(4.5236020-9.2422029e-4*day, twoPi)
stem = math.Sin(xnodce)
ctem = math.Cos(xnodce)
zcosil = 0.91375164 - 0.03568096*ctem
Expand Down Expand Up @@ -588,8 +587,8 @@ func dscom(epoch, ep, argpp, tc, inclp, nodep, np, e3, ee2, peo, pgho, pho, pinc
}
}

zmol = math.Mod(4.7199672+0.22997150*day-gam, TWOPI)
zmos = math.Mod(6.2565837+0.017201977*day, TWOPI)
zmol = math.Mod(4.7199672+0.22997150*day-gam, twoPi)
zmos = math.Mod(6.2565837+0.017201977*day, twoPi)

se2 = 2.0 * ss1 * ss6
se3 = 2.0 * ss1 * ss7
Expand Down
36 changes: 18 additions & 18 deletions helpers.go
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Expand Up @@ -7,28 +7,28 @@ import (
"strings"
)

// Constants
const TWOPI float64 = math.Pi * 2.0
const DEG2RAD float64 = math.Pi / 180.0
const RAD2DEG float64 = 180.0 / math.Pi
const XPDOTP float64 = 1440.0 / (2.0 * math.Pi)
const (
twoPi float64 = math.Pi * 2.0
deg2rad float64 = math.Pi / 180.0
xPDOTP float64 = 1440.0 / (2.0 * math.Pi)
)

// Holds latitude and Longitude in either degrees or radians
// LatLong holds latitude and Longitude in either degrees or radians
type LatLong struct {
Latitude, Longitude float64
}

// Holds X, Y, Z position
// Vector3 holds X, Y, Z position
type Vector3 struct {
X, Y, Z float64
}

// Holds an azimuth, elevation and range
// LookAngles holds an azimuth, elevation and range
type LookAngles struct {
Az, El, Rg float64
}

// Parses a two line element dataset into a Satellite struct
// ParseTLE parses a two line element dataset into a Satellite struct
func ParseTLE(line1, line2, gravconst string) (sat Satellite) {
sat.Line1 = line1
sat.Line2 = line2
Expand Down Expand Up @@ -58,23 +58,23 @@ func ParseTLE(line1, line2, gravconst string) (sat Satellite) {
return
}

// Converts a two line element data set into a Satellite struct and runs sgp4init
// TLEToSat converts a two line element data set into a Satellite struct and runs sgp4init
func TLEToSat(line1, line2 string, gravconst string) Satellite {
//sat := Satellite{Line1: line1, Line2: line2}
sat := ParseTLE(line1, line2, gravconst)

opsmode := "i"

sat.no = sat.no / XPDOTP
sat.ndot = sat.ndot / (XPDOTP * 1440.0)
sat.nddot = sat.nddot / (XPDOTP * 1440.0 * 1440)
sat.no = sat.no / xPDOTP
sat.ndot = sat.ndot / (xPDOTP * 1440.0)
sat.nddot = sat.nddot / (xPDOTP * 1440.0 * 1440)

sat.inclo = sat.inclo * DEG2RAD
sat.nodeo = sat.nodeo * DEG2RAD
sat.argpo = sat.argpo * DEG2RAD
sat.mo = sat.mo * DEG2RAD
sat.inclo = sat.inclo * deg2rad
sat.nodeo = sat.nodeo * deg2rad
sat.argpo = sat.argpo * deg2rad
sat.mo = sat.mo * deg2rad

var year int64 = 0
var year int64
if sat.epochyr < 57 {
year = sat.epochyr + 2000
} else {
Expand Down
2 changes: 0 additions & 2 deletions satellite.go
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Expand Up @@ -24,8 +24,6 @@ type Satellite struct {
argpo float64
mo float64
no float64
alta float64
altp float64

method string
operationmode string
Expand Down
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