Computes the phase model coefficients necessary for a successful demodulation. More...

Prototypes
static void	TimeToFloat (REAL8 f, LIGOTimeGPS tgps)

static void	FloatToTime (LIGOTimeGPS tgps, REAL8 f)

void	LALComputeSky (LALStatus status, REAL8 skyConst, INT8 iSkyCoh, CSParams *params)
	Given an input index which refers to the sky patch under consideration, this routine returns the phase model coefficients \( A_{s\alpha} \) and \( B_{s\alpha} \) which are needed to correctly account for the phase variance of a signal over time. More...

Detailed Description

Computes the phase model coefficients necessary for a successful demodulation.

Author: Berukoff, S.J., Papa, M.A.

Definition in file ComputeSky.c.

Go to the source code of this file.

Function Documentation

◆ TimeToFloat()

static void TimeToFloat	(	REAL8 *	f,
		LIGOTimeGPS *	tgps
	)

static

Definition at line 144 of file ComputeSky.c.

◆ FloatToTime()

static void FloatToTime	(	LIGOTimeGPS *	tgps,
		REAL8 *	f
	)

static

Definition at line 153 of file ComputeSky.c.

◆ LALComputeSky()

void LALComputeSky	(	LALStatus *	status,
		REAL8 *	skyConst,
		INT8	iSkyCoh,
		CSParams *	params
	)

Given an input index which refers to the sky patch under consideration, this routine returns the phase model coefficients \( A_{s\alpha} \) and \( B_{s\alpha} \) which are needed to correctly account for the phase variance of a signal over time.

The CSParams parameter structure contains relevant information for this routine to properly run. In particular, it contains an array of timestamps in LIGOTimeGPS format, which are the GPS times of the first data from each SFT. The input is an INT4 variable iSkyCoh, which is the index of the sky patch under consideration. For each sky patch, this code needs to be run once; the necessary phase model coefficients are calculated, and can then be applied to the relevant spindown parameter sets one is using in their search.

Algorithm

The routine uses a simplistic nested for-loop structure. The outer loop is over the number of SFTs in the observation timescale; this accounts for the temporal variability of the phase model coefficients. The inner loop is over the number of spindown parameters in one set. Inside the inner loop, the values are calculated using the analytical formulae given in the ComputeSky.h documentation.

Notes

The reference-time, at which the pulsar spin-parameters are defined, is taken to be the start-time INTERPRETED as an SSB time (i.e. no translation is done, the times are numerically equal!).

Definition at line 65 of file ComputeSky.c.