From 2e48cbc261fdf23769a3fe0d58765f01e38c93d7 Mon Sep 17 00:00:00 2001 From: fenrir Date: Sun, 3 Jul 2022 22:59:40 +0900 Subject: [PATCH 1/2] Fix F2 coefficient of ast_args() According to pp.23 of Chapter.5 of IERS Conventions (1996), F2 coefficient for 3rd power of t is -0.000136, not 0.000136. --- src/rtkcmn.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/rtkcmn.c b/src/rtkcmn.c index da9b34e1a..4ee028593 100644 --- a/src/rtkcmn.c +++ b/src/rtkcmn.c @@ -1755,7 +1755,7 @@ static void ast_args(double t, double *f) { static const double fc[][5]={ /* coefficients for iau 1980 nutation */ { 134.96340251, 1717915923.2178, 31.8792, 0.051635, -0.00024470}, - { 357.52910918, 129596581.0481, -0.5532, 0.000136, -0.00001149}, + { 357.52910918, 129596581.0481, -0.5532, -0.000136, -0.00001149}, { 93.27209062, 1739527262.8478, -12.7512, -0.001037, 0.00000417}, { 297.85019547, 1602961601.2090, -6.3706, 0.006593, -0.00003169}, { 125.04455501, -6962890.2665, 7.4722, 0.007702, -0.00005939} From e51af072c00acbe1a5f02076611303fa851ce89d Mon Sep 17 00:00:00 2001 From: fenrir Date: Mon, 4 Jul 2022 12:11:37 +0900 Subject: [PATCH 2/2] Revert F2 coefficient of ast_args() with comment --- src/rtkcmn.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/rtkcmn.c b/src/rtkcmn.c index 4ee028593..6c423705d 100644 --- a/src/rtkcmn.c +++ b/src/rtkcmn.c @@ -1755,7 +1755,9 @@ static void ast_args(double t, double *f) { static const double fc[][5]={ /* coefficients for iau 1980 nutation */ { 134.96340251, 1717915923.2178, 31.8792, 0.051635, -0.00024470}, - { 357.52910918, 129596581.0481, -0.5532, -0.000136, -0.00001149}, + { 357.52910918, 129596581.0481, -0.5532, /*-*/0.000136, -0.00001149}, + // some documents say -0.000136, however, the latest says 0.000136. see Eq.(5.36) of IERS 2010. + // https://www.iers.org/SharedDocs/Publikationen/EN/IERS/Publications/tn/TechnNote36/tn36_043.pdf#page=25 { 93.27209062, 1739527262.8478, -12.7512, -0.001037, 0.00000417}, { 297.85019547, 1602961601.2090, -6.3706, 0.006593, -0.00003169}, { 125.04455501, -6962890.2665, 7.4722, 0.007702, -0.00005939}