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Update package dependencies. Add relative orbit transforms. Fix broke…
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,242 @@ | ||
| ############## | ||
| # RTN | LVLH # | ||
| ############## | ||
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| export rRTNtoECI | ||
| export rECItoRTN | ||
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| """ | ||
| Compute the radial, along-track, cross-track (RTN) to Earth-centered inertial | ||
| rotation matrix. If applied to a position vector in the RTN frame, it will | ||
| transform that vector to into the equivalent position vector in the ECI frame. | ||
| The RTN frame is also commonly refered to as the local-vertical, local-horizontal (LVLH) frame. | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| Returns: | ||
| - `R_rtn2eci::SMatrix{3,3}`: Rotation matrix transforming _from_ the RTN frame _to_ the ECI frame | ||
| """ | ||
| function rRTNtoECI(x::AbstractVector{<:Real}) | ||
| r = x[idx1t3] | ||
| v = x[idx4t6] | ||
| n = cross(r, v) | ||
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| R = normalize(r) | ||
| N = normalize(n) | ||
| T = cross(N, R) | ||
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| R_rtn2eci = hcat(R, T, N) | ||
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| return R_rtn2eci | ||
| end | ||
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| """ | ||
| Compute the Earth-centered inertial to radial, along-track, cross-track (RTN) | ||
| rotation matrix. If applied to a position vector in the ECI frame, it will | ||
| transform that vector into the equivalent position vector in the RTN frame. | ||
| The RTN frame is also commonly refered to as the local-vertical, local-horizontal (LVLH) frame. | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| Returns: | ||
| - `R_eci2rtn::SMatrix{3,3}`: Rotation matrix transforming _from_ the ECI frame _to_ the RTN frame | ||
| """ | ||
| function rECItoRTN(x::AbstractVector{<:Real}) | ||
| r = x[idx1t3] | ||
| v = x[idx4t6] | ||
| n = cross(r, v) | ||
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| R = normalize(r) | ||
| N = normalize(n) | ||
| T = cross(N, R) | ||
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| R_eci2rtn = hcat(R, T, N)' | ||
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| return R_eci2rtn | ||
| end | ||
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| export sECItoRTN | ||
| """ | ||
| Compute the radial, along-track, cross-track (RTN) coordinates of a target satellite in the primary satellites RTN frame. | ||
| The RTN frame is also commonly refered to as the local-vertical, local-horizontal (LVLH) frame. | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| - `xt::AbstractVector{<:Real}`: Inertial state (position and velocity) of the target satellite | ||
| Returns: | ||
| - `xrtn::AbstractVector{<:Real}`: Position and velocity of the target relative of the observing satellite in the RTN. | ||
| """ | ||
| function sECItoRTN(x::AbstractVector{<:Real}, xt::AbstractVector{<:Real}) | ||
| if length(xt) >= 6 | ||
| return sECItoRTN(x, xt[idx1t6]) | ||
| else | ||
| return sECItoRTN(x, xt[idx1t3]) | ||
| end | ||
| end | ||
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| """ | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| - `xt::SVector{3,<:Real}`: Inertial state (position) of the target satellite | ||
| Returns: | ||
| - `xrtn::SVector{3,<:Real}`: Position of the target relative of the observing satellite in the RTN. | ||
| """ | ||
| function sECItoRTN(x::AbstractVector{<:Real}, xt::SVector{3,<:Real}) | ||
| # Create RTN rotation matrix | ||
| R_eci2rtn = rECItoRTN(x) | ||
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| # Transform Position | ||
| r = x[idx1t3] | ||
| rho = xt[idx1t3] - r | ||
| r_rtn = R_eci2rtn*rho | ||
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| return r_rtn | ||
| end | ||
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| """ | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| - `xt::SVector{6,<:Real}`: Inertial state (position and velocity) of the target satellite | ||
| Returns: | ||
| - `xrtn::SVector{6,<:Real}`: Position and velocity of the target relative of the observing satellite in the RTN. | ||
| """ | ||
| function sECItoRTN(x::AbstractVector{<:Real}, xt::SVector{6,<:Real}) | ||
| # Create RTN rotation matrix | ||
| R_eci2rtn = rECItoRTN(x) | ||
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| # Transform Position | ||
| r = x[idx1t3] | ||
| rho = xt[idx1t3] - r | ||
| r_rtn = R_eci2rtn*rho | ||
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| v = x[idx4t6] | ||
| f_dot = norm(cross(r, v)) / norm(r)^2 | ||
| omega = SVector(0, 0, f_dot) | ||
| rho_dot = xt[idx4t6] - v | ||
| v_rtn = R_eci2rtn*rho_dot - cross(omega, r_rtn) | ||
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| return vcat(r_rtn, v_rtn) | ||
| end | ||
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| export sRTNtoECI | ||
| """ | ||
| Compute the Earth-center | ||
| The RTN frame is also commonly refered to as the local-vertical, local-horizontal (LVLH) frame. | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| - `xrtn::AbstractVector{<:Real}`: Inertial state (position and velocity) of the target satellite | ||
| Returns: | ||
| - `xt::AbstractVector{<:Real}`: Position and velocity of the target relative of the observing satellite in the RTN. | ||
| """ | ||
| function sRTNtoECI(x::AbstractVector{<:Real}, xrtn::AbstractVector{<:Real}) | ||
| if length(xrtn) >= 6 | ||
| return sRTNtoECI(x, xrtn[idx1t6]) | ||
| else | ||
| return sRTNtoECI(x, xrtn[idx1t3]) | ||
| end | ||
| end | ||
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| """ | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| - `xrtn::SVector{3,<:Real}`: Inertial state (position) of the target satellite | ||
| Returns: | ||
| - `xt::SVector{3,<:Real}`: Position of the target relative of the observing satellite in the RTN. | ||
| """ | ||
| function sRTNtoECI(x::AbstractVector{<:Real}, xrtn::SVector{3,<:Real}) | ||
| # Create RTN rotation matrix | ||
| R_rtn2eci = rRTNtoECI(x) | ||
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| # Transform position | ||
| r = x[idx1t3] | ||
| r_t = R_rtn2eci*xrtn + r | ||
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| return r_t | ||
| end | ||
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| """ | ||
| Arguments: | ||
| - `x::AbstractVector{<:Real}`: Inertial state (position and velocity) of primary (observing) satellite | ||
| - `xrtn::SVector{6,<:Real}`: Inertial state (position and velocity) of the target satellite | ||
| Returns: | ||
| - `xt::SVector{6,<:Real}`: Position and velocity of the target relative of the observing satellite in the RTN. | ||
| """ | ||
| function sRTNtoECI(x::AbstractVector{<:Real}, xrtn::SVector{6,<:Real}) | ||
| # Create RTN rotation matrix | ||
| R_rtn2eci = rRTNtoECI(x) | ||
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| # Transform position | ||
| r = x[idx1t3] | ||
| r_rtn = xrtn[idx1t3] | ||
| r_t = R_rtn2eci*r_rtn + r | ||
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| # Transform velocity | ||
| v = x[idx4t6] | ||
| v_rtn = xrtn[idx4t6] | ||
| f_dot = norm(cross(r, v)) / norm(r)^2 | ||
| omega = SVector(0, 0, f_dot) | ||
| v_t = R_rtn2eci*(v_rtn + cross(omega, r_rtn)) + v | ||
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| return vcat(r_t, v_t) | ||
| end | ||
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| ####### | ||
| # ROE # | ||
| ####### | ||
|
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| """ | ||
| Convert Keplerian relative orbital element state to ROE relative state | ||
| """ | ||
| function sOSCtoROE(oe_c::SVector{6,<:Real}, oe_d::SVector{6,<:Real}) | ||
| end | ||
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| """ | ||
| Convert ROE relative state and chief relative orbital elements and return | ||
| osculating orbital elements | ||
| """ | ||
| function sROEtoOSC(oe_c::SVector{6,<:Real}, roe_d::SVector{6,<:Real}) | ||
| end | ||
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| """ | ||
| Convert inertial states to relative orbital element | ||
| """ | ||
| function sECItoROE(x_c::SVector{6,<:Real}, x_d::SVector{6,<:Real}) | ||
| end | ||
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| """ | ||
| Convert ROE relative state and chief absolute inertial state and return | ||
| osculating orbital elements | ||
| """ | ||
| function sROEtoECI(x_c::SVector{6,<:Real}, roe_d::SVector{6,<:Real}) | ||
| end | ||
|
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| """ | ||
| Convert RTN state and chief absolute inertial state and return relative | ||
| orbital element state | ||
| """ | ||
| function sRTNtoROE(x_c::SVector{6,<:Real}, rtn_d::SVector{6,<:Real}) | ||
| end | ||
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| """ | ||
| Covert relative orbital element state and chief inertial state and return | ||
| RTN state. | ||
| """ | ||
| function sROEtoRTN(x_c::SVector{6,<:Real}, roe_d::SVector{6,<:Real}) | ||
| end |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,53 @@ | ||
| let | ||
| epc = Epoch(2018,1,1,12,0,0) | ||
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| a = R_EARTH + 500e3 | ||
| oe = [a, 0, 0, 0, 0, sqrt(GM_EARTH/a)] | ||
| eci = sOSCtoCART(oe, use_degrees=true) | ||
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| r_rtn = rRTNtoECI(eci) | ||
| r_rtn_t = rECItoRTN(eci) | ||
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| r = r_rtn * r_rtn_t | ||
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| tol = 1e-8 | ||
| @test isapprox(r[1, 1], 1.0, atol=tol) | ||
| @test isapprox(r[1, 2], 0.0, atol=tol) | ||
| @test isapprox(r[1, 3], 0.0, atol=tol) | ||
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| @test isapprox(r[2, 1], 0.0, atol=tol) | ||
| @test isapprox(r[2, 2], 1.0, atol=tol) | ||
| @test isapprox(r[2, 3], 0.0, atol=tol) | ||
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| @test isapprox(r[3, 1], 0.0, atol=tol) | ||
| @test isapprox(r[3, 2], 0.0, atol=tol) | ||
| @test isapprox(r[3, 3], 1.0, atol=tol) | ||
| end | ||
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| let | ||
| epc = Epoch(2018,1,1,12,0,0) | ||
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| oe = [R_EARTH + 500e3, 0, 0, 0, 0, 0] | ||
| eci = sOSCtoCART(oe, use_degrees=true) | ||
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| xt = deepcopy(eci) + [100, 0, 0, 0, 0, 0] | ||
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| x_rtn = sECItoRTN(eci, xt) | ||
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| tol = 1e-8 | ||
| @test isapprox(x_rtn[1], 100.0, atol=tol) | ||
| @test isapprox(x_rtn[2], 0.0, atol=tol) | ||
| @test isapprox(x_rtn[3], 0.0, atol=tol) | ||
| @test isapprox(x_rtn[4], 0.0, atol=tol) | ||
| @test isapprox(x_rtn[5], 0.0, atol=0.5) | ||
| @test isapprox(x_rtn[6], 0.0, atol=tol) | ||
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| xt2 = sRTNtoECI(eci, x_rtn) | ||
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| @test isapprox(xt[1], xt2[1], atol=tol) | ||
| @test isapprox(xt[2], xt2[2], atol=tol) | ||
| @test isapprox(xt[3], xt2[3], atol=tol) | ||
| @test isapprox(xt[4], xt2[4], atol=tol) | ||
| @test isapprox(xt[5], xt2[5], atol=tol) | ||
| @test isapprox(xt[6], xt2[6], atol=tol) | ||
| end |