🔧 Update lighting_condition

src/lighting_condition.jl

@@ -1,53 +1,62 @@
-# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 #
 # Description
-# ==============================================================================
+# ==========================================================================================
 #
 # Compute the satellite lighting condition considering the Earth eclipse.
 #
-# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 #
 # References
-# ==============================================================================
+# ==========================================================================================
 #
-# [1] Longo, C. R. O., Rickman, S. L (1995). Method for the Calculation of
-# Spacecraft Umbra and Penumbra Shadow Terminator Points. NASA Technical
-# Paper 3547.
+# [1] Longo, C. R. O., Rickman, S. L (1995). Method for the Calculation of Spacecraft Umbra
+# and Penumbra Shadow Terminator Points. NASA Technical Paper 3547.
 #
-# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 
 export lighting_condition
 
 """
  lighting_condition(r_i::AbstractVector, s_i::AbstractVector)
 
-Compute the lighting condition at the position `r_i` [m] considering the Sun
-position vector `s_i` [m]. The possible return values are:
+Compute the lighting condition at the position `r_i` [m] considering the Sun position vector
+`s_i` [m]. The possible return values are:
 
 - `:sunlight`: The point is under direct sunlight.
 - `:penumbra`: The point is in penumbra region.
 - `:umbra`: The point is in umbra region.
 
+The algorithm used in this function was based on **[1]**.
+
 !!! note
  The vectors `r_i` and `s_i` must be represented in the same reference frame.
+
+# References
+
+- **[1]** Longo, C. R. O., Rickman, S. L (1995). Method for the Calculation of Spacecraft
+ Umbra and Penumbra Shadow Terminator Points. NASA Technical Paper 3547.
 """
 function lighting_condition(r_i::AbstractVector, s_i::AbstractVector)
+ # Constants.
+ R₀ = EARTH_EQUATORIAL_RADIUS
+ Rs = SUN_RADIUS
+
  # Distance from the Earth to the Sun.
  norm_s_i = norm(s_i)
 
  # Projection of the satellite position vector on the Sun direction [1].
  rs_i = (r_i ⋅ s_i) * s_i / (norm_s_i * norm_s_i)
 
  # Check if the satellite is under sunlight, umbra or penumbra.
-
  if (rs_i ⋅ s_i / norm_s_i) < 0
  # Distance of the umbral cone and the spacecraft [1].
  Δ_i = r_i - rs_i
  norm_Δ_i = norm(Δ_i)
 
  # Penumbra section [1].
- xp = R0 * norm_s_i / (Rs + R0)
- αp = asin(R0 / xp)
+ xp = R₀ * norm_s_i / (Rs + R₀)
+ αp = asin(R₀ / xp)
 
  # Location of the penumbral cone terminator at the projected spacecraft
  # location [1].
@@ -57,8 +66,8 @@ function lighting_condition(r_i::AbstractVector, s_i::AbstractVector)
  return :sunlight
  else
  # Umbra section [1].
- xu = R0 * norm_s_i / (Rs - R0)
- αu = asin(R0 / xu)
+ xu = R₀ * norm_s_i / (Rs - R₀)
+ αu = asin(R₀ / xu)
 
  # Location of the umbral cone terminator at the projected spacecraft
  # location [1].

test/lighting_condition.jl

@@ -1,34 +1,34 @@
-# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 #
 # Description
-# ==============================================================================
+# ==========================================================================================
 #
 # Tests related to lighting condition analysis.
 #
-# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 
 # File: ./src/lighting_condition.jl
-# ==============================================================================
+# ==========================================================================================
 
 # Function: lighting_condition
-# ------------------------------------------------------------------------------
+# ------------------------------------------------------------------------------------------
 
 @testset "Function lighting_condition" begin
  jd = date_to_jd(2021, 12, 8, 0, 0, 25)
- s_i = sun_position_i(jd)
+ s_i = sun_position_mod(jd)
 
  r_i = SVector(1.06746e6, 3.22132e6, -6.2841e6)
  lc = lighting_condition(r_i, s_i)
- @test lc === :sunlight
+ @test lc == :sunlight
 
  r_i = SVector(2.52449e6, 4.89401e6, -4.54648e6)
  lc = lighting_condition(r_i, s_i)
- @test lc === :penumbra
+ @test lc == :penumbra
 
  r_i = SVector(3.9575e6, 5.91988e6, -489577.0)
  lc = lighting_condition(r_i, s_i)
- @test lc === :umbra
+ @test lc == :umbra
 
  lc = lighting_condition(s_i / norm(s_i) * 7000e3, s_i)
- @test lc === :sunlight
+ @test lc == :sunlight
 end

test/runtests.jl

@@ -8,9 +8,9 @@ using SatelliteAnalysis
  include("./beta_angle.jl")
 end
 
-# @testset "Lighting condition" verbose = true begin
-#  include("./lighting_condition.jl")
-# end
+@testset "Lighting condition" verbose = true begin
+ include("./lighting_condition.jl")
+end
 
 # @testset "Miscellaneous" verbose = true begin
 # include("./misc.jl")