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Fix off-center gaussian position angle #229

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Fix off-center gaussian position angle #229

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460ba93
Start fixing Gaussian position angle
tammojan Sep 13, 2019
60a511e
Weet niet of dit klopt
tammojan Nov 28, 2019
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22 changes: 16 additions & 6 deletions DPPP/Simulator.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,7 @@ void Simulator::simulate(const ModelComponent::ConstPtr &component)

void Simulator::visit(const PointSource &component) {
// Compute LMN coordinates.
double lmn[3];
double lmn[4];
radec2lmn(itsReference, component.position(), lmn);

// Compute station phase shifts.
Expand Down Expand Up @@ -155,7 +155,7 @@ void Simulator::visit(const PointSource &component) {
void Simulator::visit(const GaussianSource &component)
{
// Compute LMN coordinates.
double lmn[3];
double lmn[4];
radec2lmn(itsReference, component.position(), lmn);

// Compute station phase shifts.
Expand Down Expand Up @@ -262,14 +262,24 @@ inline void radec2lmn(const Position &reference, const Position &position,
const double dRA = position[0] - reference[0];
const double pDEC = position[1];
const double rDEC = reference[1];
const double cDEC = cos(pDEC);

const double l = cDEC * sin(dRA);
const double m = sin(pDEC) * cos(rDEC) - cDEC * sin(rDEC) * cos(dRA);
const double sdRA = sin(dRA);
const double cdRA = cos(dRA);
const double spDEC = sin(pDEC);
const double cpDEC = cos(pDEC);
const double srDEC = sin(rDEC);
const double crDEC = cos(rDEC);

const double l = cpDEC * sdRA;
const double m = spDEC * crDEC - cpDEC * srDEC * cdRA;
// Derivative of l, m w.r.t. declination, needed for position angle
const double lprime = -sdRA * spDEC;
const double mprime = cpDEC * crDEC + cdRA * spDEC * srDEC;
const double correction = atan2(lprime, mprime);

lmn[0] = l;
lmn[1] = m;
lmn[2] = sqrt(1.0 - l * l - m * m);
lmn[3] = correction;
}

// Compute station phase shifts.
Expand Down