1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
* geoid.c -- ECEF to WGS84 conversions, including ellipsoid-to-MSL height
*
* Geoid separation code by Oleg Gusev, from data by Peter Dana.
* ECEF conversion by Rob Janssen.
*/
#include <math.h>
#include "gpsd.h"
static double bilinear(double x1, double y1, double x2, double y2, double x, double y, double z11, double z12, double z21, double z22)
{
double delta;
if (y1 == y2 && x1 == x2 ) return (z11);
if (y1 == y2 && x1 != x2 ) return (z22*(x-x1)+z11*(x2-x))/(x2-x1);
if (x1 == x2 && y1 != y2 ) return (z22*(y-y1)+z11*(y2-y))/(y2-y1);
delta=(y2-y1)*(x2-x1);
return (z22*(y-y1)*(x-x1)+z12*(y2-y)*(x-x1)+z21*(y-y1)*(x2-x)+z11*(y2-y)*(x2-x))/delta;
}
/* return geoid separtion (MSL - WGS84) in meters, given a lat/lot in degrees */
/*@ +charint @*/
double wgs84_separation(double lat, double lon)
{
#define GEOID_ROW 19
#define GEOID_COL 37
const char geoid_delta[GEOID_COL*GEOID_ROW]={
/* 90S */ -30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30, -30,-30,-30,-30,-30,-30,-30,-30,-30,-30,-30,
/* 80S */ -53,-54,-55,-52,-48,-42,-38,-38,-29,-26,-26,-24,-23,-21,-19,-16,-12, -8, -4, -1, 1, 4, 4, 6, 5, 4, 2, -6,-15,-24,-33,-40,-48,-50,-53,-52,-53,
/* 70S */ -61,-60,-61,-55,-49,-44,-38,-31,-25,-16, -6, 1, 4, 5, 4, 2, 6, 12, 16, 16, 17, 21, 20, 26, 26, 22, 16, 10, -1,-16,-29,-36,-46,-55,-54,-59,-61,
/* 60S */ -45,-43,-37,-32,-30,-26,-23,-22,-16,-10, -2, 10, 20, 20, 21, 24, 22, 17, 16, 19, 25, 30, 35, 35, 33, 30, 27, 10, -2,-14,-23,-30,-33,-29,-35,-43,-45,
/* 50S */ -15,-18,-18,-16,-17,-15,-10,-10, -8, -2, 6, 14, 13, 3, 3, 10, 20, 27, 25, 26, 34, 39, 45, 45, 38, 39, 28, 13, -1,-15,-22,-22,-18,-15,-14,-10,-15,
/* 40S */ 21, 6, 1, -7,-12,-12,-12,-10, -7, -1, 8, 23, 15, -2, -6, 6, 21, 24, 18, 26, 31, 33, 39, 41, 30, 24, 13, -2,-20,-32,-33,-27,-14, -2, 5, 20, 21,
/* 30S */ 46, 22, 5, -2, -8,-13,-10, -7, -4, 1, 9, 32, 16, 4, -8, 4, 12, 15, 22, 27, 34, 29, 14, 15, 15, 7, -9,-25,-37,-39,-23,-14, 15, 33, 34, 45, 46,
/* 20S */ 51, 27, 10, 0, -9,-11, -5, -2, -3, -1, 9, 35, 20, -5, -6, -5, 0, 13, 17, 23, 21, 8, -9,-10,-11,-20, -40,-47,-45,-25, 5, 23, 45, 58, 57, 63, 51,
/* 10S */ 36, 22, 11, 6, -1, -8,-10, -8,-11, -9, 1, 32, 4,-18,-13, -9, 4, 14, 12, 13, -2,-14,-25,-32,-38,-60, -75,-63,-26, 0, 35, 52, 68, 76, 64, 52, 36,
/* 00N */ 22, 16, 17, 13, 1,-12,-23,-20,-14, -3, 14, 10,-15,-27,-18, 3, 12, 20, 18, 12,-13, -9,-28,-49,-62,-89,-102,-63, -9, 33, 58, 73, 74, 63, 50, 32, 22,
/* 10N */ 13, 12, 11, 2,-11,-28,-38,-29,-10, 3, 1,-11,-41,-42,-16, 3, 17, 33, 22, 23, 2, -3, -7,-36,-59,-90, -95,-63,-24, 12, 53, 60, 58, 46, 36, 26, 13,
/* 20N */ 5, 10, 7, -7,-23,-39,-47,-34, -9,-10,-20,-45,-48,-32, -9, 17, 25, 31, 31, 26, 15, 6, 1,-29,-44,-61, -67,-59,-36,-11, 21, 39, 49, 39, 22, 10, 5,
/* 30N */ -7, -5, -8,-15,-28,-40,-42,-29,-22,-26,-32,-51,-40,-17, 17, 31, 34, 44, 36, 28, 29, 17, 12,-20,-15,-40, -33,-34,-34,-28, 7, 29, 43, 20, 4, -6, -7,
/* 40N */ -12,-10,-13,-20,-31,-34,-21,-16,-26,-34,-33,-35,-26, 2, 33, 59, 52, 51, 52, 48, 35, 40, 33, -9,-28,-39, -48,-59,-50,-28, 3, 23, 37, 18, -1,-11,-12,
/* 50N */ -8, 8, 8, 1,-11,-19,-16,-18,-22,-35,-40,-26,-12, 24, 45, 63, 62, 59, 47, 48, 42, 28, 12,-10,-19,-33, -43,-42,-43,-29, -2, 17, 23, 22, 6, 2, -8,
/* 60N */ 2, 9, 17, 10, 13, 1,-14,-30,-39,-46,-42,-21, 6, 29, 49, 65, 60, 57, 47, 41, 21, 18, 14, 7, -3,-22, -29,-32,-32,-26,-15, -2, 13, 17, 19, 6, 2,
/* 70N */ 2, 2, 1, -1, -3, -7,-14,-24,-27,-25,-19, 3, 24, 37, 47, 60, 61, 58, 51, 43, 29, 20, 12, 5, -2,-10, -14,-12,-10,-14,-12, -6, -2, 3, 6, 4, 2,
/* 80N */ 3, 1, -2, -3, -3, -3, -1, 3, 1, 5, 9, 11, 19, 27, 31, 34, 33, 34, 33, 34, 28, 23, 17, 13, 9, 4, 4, 1, -2, -2, 0, 2, 3, 2, 1, 1, 3,
/* 90N */ 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13};
/*@ -charint @*/
int ilat, ilon;
int ilat1, ilat2, ilon1, ilon2;
ilat=(int)floor(( 90.+lat)/10);
ilon=(int)floor((180.+lon)/10);
ilat1=ilat;
ilon1=ilon;
ilat2=(ilat < GEOID_ROW-1)? ilat+1:ilat;
ilon2=(ilon < GEOID_COL-1)? ilon+1:ilon;
return bilinear(
ilon1*10.-180.,ilat1*10.-90.,
ilon2*10.-180.,ilat2*10.-90.,
lon, lat,
(double)geoid_delta[ilon1+ilat1*GEOID_COL],
(double)geoid_delta[ilon2+ilat1*GEOID_COL],
(double)geoid_delta[ilon1+ilat2*GEOID_COL],
(double)geoid_delta[ilon2+ilat2*GEOID_COL]
);
}
void ecef_to_wgs84fix(struct gps_data_t *gpsdata,
double x, double y, double z,
double vx, double vy, double vz)
/* fill in WGS84 position/velocity fields from ECEF coordinates */
{
double lambda,phi,p,theta,n,h,vnorth,veast,heading;
const double a = 6378137; /* equatorial radius */
const double f = 1 / 298.257223563; /* flattening */
const double b = a * (1 - f); /* polar radius */
const double e2 = (a*a - b*b) / (a*a);
const double e_2 = (a*a - b*b) / (b*b);
/* geodetic location */
lambda = atan2(y,x);
/*@ -evalorder @*/
p = sqrt(pow(x,2) + pow(y,2));
theta = atan2(z*a,p*b);
phi = atan2(z + e_2*b*pow(sin(theta),3),p - e2*a*pow(cos(theta),3));
n = a / sqrt(1.0 - e2*pow(sin(phi),2));
h = p / cos(phi) - n;
gpsdata->newdata.latitude = phi * RAD_2_DEG;
gpsdata->newdata.longitude = lambda * RAD_2_DEG;
gpsdata->separation = wgs84_separation(gpsdata->newdata.latitude, gpsdata->newdata.longitude);
gpsdata->newdata.altitude = h - gpsdata->separation;
/* velocity computation */
vnorth = -vx*sin(phi)*cos(lambda)-vy*sin(phi)*sin(lambda)+vz*cos(phi);
veast = -vx*sin(lambda)+vy*cos(lambda);
gpsdata->newdata.climb = vx*cos(phi)*cos(lambda)+vy*cos(phi)*sin(lambda)+vz*sin(phi);
gpsdata->newdata.speed = sqrt(pow(vnorth,2) + pow(veast,2));
heading = atan2(veast,vnorth);
/*@ +evalorder @*/
if (heading < 0)
heading += 2 * PI;
gpsdata->newdata.track = heading * RAD_2_DEG;
}
#ifdef TESTMAIN
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
double lat, lon;
if (argc != 3) {
fprintf(stderr,"Usage: %s lat lon\n",argv[0]);
return 1;
}
lat=atof(argv[1]);
lon=atof(argv[2]);
if (lat > 90. || lat < -90.)
{
fprintf(stderr," -90 <= lat=%s(%.f) <= 90 ?\n",argv[1],lat);
return 1;
}
if (lon > 180. || lat < -180.)
{
fprintf(stderr," -180 <= lon=%s(%.f) <= 180 ?\n",argv[2],lon);
return 1;
}
printf(" lat= %f lon= %f geoid correction= %f\n",
lat, lon, wgs84_separation(lat, lon));
return 0;
}
#endif /* TESTMAIN */
|
