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|
/* subframe.c -- interpret satellite subframe data.
*
* This file is Copyright (c) 2010 by the GPSD project
* BSD terms apply: see the file COPYING in the distribution root for details.
*/
#include <math.h>
#include "gpsd.h"
/* convert unsigned to signed */
#define uint2int( u, bit) ( u & (1<<(bit-1)) ? u - (1<<bit) : u)
/*@ -usedef @*/
gps_mask_t gpsd_interpret_subframe_raw(struct gps_device_t *session,
unsigned int tSVID, uint32_t words[])
{
unsigned int i;
uint8_t preamble;
uint32_t parity;
if (session->subframe_count++ == 0) {
speed_t speed = gpsd_get_speed(session);
if (speed < 38400)
gpsd_report(session->context->debug, LOG_WARN,
"speed less than 38,400 may cause data lag and loss of functionality\n");
}
/*
* This function assumes an array of 10 ints, each of which carries
* a raw 30-bit GPS word use your favorite search engine to find the
* latest version of the specification: IS-GPS-200.
*
* Each raw 30-bit word is made of 24 data bits and 6 parity bits. The
* raw word and transport word are emitted from the GPS MSB-first and
* right justified. In other words, masking the raw word against 0x3f
* will return just the parity bits. Masking with 0x3fffffff and shifting
* 6 bits to the right returns just the 24 data bits. The top two bits
* (b31 and b30) are undefined; chipset designers may store copies of
* the bits D29* and D30* here to aid parity checking.
*
* Since bits D29* and D30* are not available in word 0, it is tested for
* a known preamble to help check its validity and determine whether the
* word is inverted.
*
*/
gpsd_report(session->context->debug, LOG_DATA,
"50B: gpsd_interpret_subframe_raw: "
"%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x\n",
words[0], words[1], words[2], words[3], words[4],
words[5], words[6], words[7], words[8], words[9]);
preamble = (uint8_t)((words[0] >> 22) & 0xFF);
if (preamble == 0x8b) { /* preamble is inverted */
words[0] ^= 0x3fffffc0; /* invert */
} else if (preamble != 0x74) {
/* strangely this is very common, so don't log it */
gpsd_report(session->context->debug, LOG_DATA,
"50B: gpsd_interpret_subframe_raw: bad preamble 0x%x\n",
preamble);
return 0;
}
words[0] = (words[0] >> 6) & 0xffffff;
for (i = 1; i < 10; i++) {
int invert;
/* D30* says invert */
invert = (words[i] & 0x40000000) ? 1 : 0;
/* inverted data, invert it back */
if (invert) {
words[i] ^= 0x3fffffc0;
}
parity = (uint32_t)isgps_parity((isgps30bits_t)words[i]);
if (parity != (words[i] & 0x3f)) {
gpsd_report(session->context->debug, LOG_DATA,
"50B: gpsd_interpret_subframe_raw parity fail words[%d] 0x%x != 0x%x\n",
i, parity, (words[i] & 0x1));
return 0;
}
words[i] = (words[i] >> 6) & 0xffffff;
}
return gpsd_interpret_subframe(session, tSVID, words);
}
/* you can find up to date almanac data for comparision here:
* https://gps.afspc.af.mil/gps/Current/current.alm
*/
static void subframe_almanac(uint8_t tSVID, uint32_t words[],
uint8_t subframe, uint8_t sv,
uint8_t data_id,
/*@out@*/struct almanac_t *almp,
const int debug)
{
/*@+matchanyintegral -shiftimplementation@*/
almp->sv = sv; /* ignore the 0 sv problem for now */
almp->e = ( words[2] & 0x00FFFF);
almp->d_eccentricity = pow(2.0,-21) * almp->e;
/* carefull, each SV can have more than 2 toa's active at the same time
* you can not just store one or two almanacs for each sat */
almp->toa = ((words[3] >> 16) & 0x0000FF);
almp->l_toa = almp->toa << 12;
almp->deltai = ( words[3] & 0x00FFFF);
almp->d_deltai = pow(2.0, -19) * almp->deltai;
almp->Omegad = ((words[4] >> 8) & 0x00FFFF);
almp->d_Omegad = pow(2.0, -38) * almp->Omegad;
almp->svh = ( words[4] & 0x0000FF);
almp->sqrtA = ( words[5] & 0xFFFFFF);
almp->d_sqrtA = pow(2.0,-11) * almp->sqrtA;
almp->Omega0 = ( words[6] & 0xFFFFFF);
almp->Omega0 = uint2int(almp->Omega0, 24);
almp->d_Omega0 = pow(2.0, -23) * almp->Omega0;
almp->omega = ( words[7] & 0xFFFFFF);
almp->omega = uint2int(almp->omega, 24);
almp->d_omega = pow(2.0, -23) * almp->omega;
almp->M0 = ( words[8] & 0x00FFFFFF);
almp->M0 = uint2int(almp->M0, 24);
/* if you want radians, multiply by GPS_PI, but we do semi-circles
* to match IS-GPS-200E */
almp->d_M0 = pow(2.0,-23) * almp->M0;
almp->af1 = ((words[9] >> 5) & 0x0007FF);
almp->af1 = (short)uint2int(almp->af1, 11);
almp->d_af1 = pow(2.0,-38) * almp->af1;
almp->af0 = ((words[9] >> 16) & 0x0000FF);
almp->af0 <<= 3;
almp->af0 |= ((words[9] >> 2) & 0x000007);
almp->af0 = (short)uint2int(almp->af0, 11);
almp->d_af0 = pow(2.0,-20) * almp->af0;
gpsd_report(debug, LOG_PROG,
"50B: SF:%d SV:%2u TSV:%2u data_id %d e:%g toa:%lu "
"deltai:%.10e Omegad:%.5e svh:%u sqrtA:%.10g Omega0:%.10e "
"omega:%.10e M0:%.11e af0:%.5e af1:%.5e\n",
subframe, almp->sv, tSVID, data_id,
almp->d_eccentricity,
almp->l_toa,
almp->d_deltai,
almp->d_Omegad,
almp->svh,
almp->d_sqrtA,
almp->d_Omega0,
almp->d_omega,
almp->d_M0,
almp->d_af0,
almp->d_af1);
/*@-matchanyintegral -shiftimplementation@*/
}
gps_mask_t gpsd_interpret_subframe(struct gps_device_t *session,
unsigned int tSVID, uint32_t words[])
{
/*
* Heavy black magic begins here!
*
* A description of how to decode these bits is at
* <http://home-2.worldonline.nl/~samsvl/nav2eu.htm>
*
* We're mostly looking for subframe 4 page 18 word 9, the leap second
* correction. This functions assumes an array of words without parity
* or inversion (inverted word 0 is OK). It may be called directly by a
* driver if the chipset emits acceptable data.
*
* To date this code has been tested on iTrax, SiRF and ublox.
*/
/* FIXME!! I really doubt this is Big Endian compatible */
uint8_t preamble;
struct subframe_t *subp = &session->gpsdata.subframe;
gpsd_report(session->context->debug, LOG_DATA,
"50B: gpsd_interpret_subframe: (%d) "
"%06x %06x %06x %06x %06x %06x %06x %06x %06x %06x\n",
tSVID, words[0], words[1], words[2], words[3], words[4],
words[5], words[6], words[7], words[8], words[9]);
preamble = (uint8_t)((words[0] >> 16) & 0x0FF);
if (preamble == 0x8b) {
/* somehow missed an inversion */
preamble ^= 0xff;
words[0] ^= 0xffffff;
}
if (preamble != 0x74) {
gpsd_report(session->context->debug, LOG_WARN,
"50B: gpsd_interpret_subframe bad preamble: 0x%x header 0x%x\n",
preamble, words[0]);
return 0;
}
subp->integrity = (bool)((words[0] >> 1) & 0x01);
/* The subframe ID is in the Hand Over Word (page 80) */
subp->TOW17 = ((words[1] >> 7) & 0x01FFFF);
subp->l_TOW17 = (long)(subp->TOW17 * 6);
subp->tSVID = (uint8_t)tSVID;
subp->subframe_num = ((words[1] >> 2) & 0x07);
subp->alert = (bool)((words[1] >> 6) & 0x01);
subp->antispoof = (bool)((words[1] >> 6) & 0x01);
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:%d SV:%2u TOW17:%7lu Alert:%u AS:%u IF:%d\n",
subp->subframe_num, subp->tSVID, subp->l_TOW17,
(unsigned)subp->alert, (unsigned)subp->antispoof,
(unsigned)subp->integrity);
/*
* Consult the latest revision of IS-GPS-200 for the mapping
* between magic SVIDs and pages.
*/
subp->pageid = (words[2] >> 16) & 0x00003F; /* only in frames 4 & 5 */
subp->data_id = (words[2] >> 22) & 0x3; /* only in frames 4 & 5 */
subp->is_almanac = 0;
switch (subp->subframe_num) {
case 1:
/* subframe 1: clock parameters for transmitting SV */
/* get Week Number (WN) from subframe 1 */
/*
* This only extracts 10 bits of GPS week.
* 13 bits are available in the extension CNAV message,
* which we don't decode yet because we don't know
* of any receiver that reports it.
*/
session->context->gps_week =
(unsigned short)((words[2] >> 14) & 0x03ff);
subp->sub1.WN = (uint16_t)session->context->gps_week;
subp->sub1.l2 = (uint8_t)((words[2] >> 12) & 0x000003); /* L2 Code */
subp->sub1.ura = (unsigned int)((words[2] >> 8) & 0x00000F); /* URA Index */
subp->sub1.hlth = (unsigned int)((words[2] >> 2) & 0x00003F); /* SV health */
subp->sub1.IODC = (words[2] & 0x000003); /* IODC 2 MSB */
subp->sub1.l2p = ((words[3] >> 23) & 0x000001); /* L2 P flag */
subp->sub1.Tgd = (int8_t)( words[6] & 0x0000FF);
subp->sub1.d_Tgd = pow(2.0, -31) * (int)subp->sub1.Tgd;
subp->sub1.toc = ( words[7] & 0x00FFFF);
subp->sub1.l_toc = (long)subp->sub1.toc << 4;
subp->sub1.af2 = (int8_t)((words[8] >> 16) & 0x0FF);
subp->sub1.d_af2 = pow(2.0, -55) * (int)subp->sub1.af2;
subp->sub1.af1 = (int16_t)( words[8] & 0x00FFFF);
subp->sub1.d_af1 = pow(2.0, -43) * subp->sub1.af1;
subp->sub1.af0 = (int32_t)((words[9] >> 2) & 0x03FFFFF);
subp->sub1.af0 = uint2int(subp->sub1.af0, 22);
subp->sub1.d_af0 = pow(2.0, -31) * subp->sub1.af0;
subp->sub1.IODC <<= 8;
subp->sub1.IODC |= ((words[7] >> 16) & 0x00FF);
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:1 SV:%2u WN:%4u IODC:%4u"
" L2:%u ura:%u hlth:%u L2P:%u Tgd:%g toc:%lu af2:%.4g"
" af1:%.6e af0:%.7e\n",
subp->tSVID,
subp->sub1.WN,
subp->sub1.IODC,
subp->sub1.l2,
subp->sub1.ura,
subp->sub1.hlth,
subp->sub1.l2p,
subp->sub1.d_Tgd,
subp->sub1.l_toc,
subp->sub1.d_af2,
subp->sub1.d_af1,
subp->sub1.d_af0);
break;
case 2:
/* subframe 2: ephemeris for transmitting SV */
subp->sub2.IODE = ((words[2] >> 16) & 0x00FF);
subp->sub2.Crs = (int16_t)( words[2] & 0x00FFFF);
subp->sub2.d_Crs = pow(2.0,-5) * subp->sub2.Crs;
subp->sub2.deltan = (int16_t)((words[3] >> 8) & 0x00FFFF);
subp->sub2.d_deltan = pow(2.0,-43) * subp->sub2.deltan;
subp->sub2.M0 = (int32_t)( words[3] & 0x0000FF);
subp->sub2.M0 <<= 24;
subp->sub2.M0 |= ( words[4] & 0x00FFFFFF);
subp->sub2.d_M0 = pow(2.0,-31) * subp->sub2.M0 * GPS_PI;
subp->sub2.Cuc = (int16_t)((words[5] >> 8) & 0x00FFFF);
subp->sub2.d_Cuc = pow(2.0,-29) * subp->sub2.Cuc;
subp->sub2.e = ( words[5] & 0x0000FF);
subp->sub2.e <<= 24;
subp->sub2.e |= ( words[6] & 0x00FFFFFF);
subp->sub2.d_eccentricity = pow(2.0,-33) * subp->sub2.e;
subp->sub2.Cus = (int16_t)((words[7] >> 8) & 0x00FFFF);
subp->sub2.d_Cus = pow(2.0,-29) * subp->sub2.Cus;
subp->sub2.sqrtA = ( words[7] & 0x0000FF);
subp->sub2.sqrtA <<= 24;
subp->sub2.sqrtA |= ( words[8] & 0x00FFFFFF);
subp->sub2.d_sqrtA = pow(2.0, -19) * subp->sub2.sqrtA;
subp->sub2.toe = ((words[9] >> 8) & 0x00FFFF);
subp->sub2.l_toe = (long)(subp->sub2.toe << 4);
subp->sub2.fit = ((words[9] >> 7) & 0x000001);
subp->sub2.AODO = ((words[9] >> 2) & 0x00001F);
subp->sub2.u_AODO = subp->sub2.AODO * 900;
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:2 SV:%2u IODE:%3u Crs:%.6e deltan:%.6e "
"M0:%.11e Cuc:%.6e e:%f Cus:%.6e sqrtA:%.11g "
"toe:%lu FIT:%u AODO:%5u\n",
subp->tSVID,
subp->sub2.IODE,
subp->sub2.d_Crs,
subp->sub2.d_deltan,
subp->sub2.d_M0,
subp->sub2.d_Cuc,
subp->sub2.d_eccentricity,
subp->sub2.d_Cus,
subp->sub2.d_sqrtA,
subp->sub2.l_toe,
subp->sub2.fit,
subp->sub2.u_AODO);
break;
case 3:
/* subframe 3: ephemeris for transmitting SV */
subp->sub3.Cic = (int16_t)((words[2] >> 8) & 0x00FFFF);
subp->sub3.d_Cic = pow(2.0, -29) * subp->sub3.Cic;
subp->sub3.Omega0 = (int32_t)(words[2] & 0x0000FF);
subp->sub3.Omega0 <<= 24;
subp->sub3.Omega0 |= ( words[3] & 0x00FFFFFF);
subp->sub3.d_Omega0 = pow(2.0, -31) * subp->sub3.Omega0;
subp->sub3.Cis = (int16_t)((words[4] >> 8) & 0x00FFFF);
subp->sub3.d_Cis = pow(2.0, -29) * subp->sub3.Cis;
subp->sub3.i0 = (int32_t)(words[4] & 0x0000FF);
subp->sub3.i0 <<= 24;
subp->sub3.i0 |= ( words[5] & 0x00FFFFFF);
subp->sub3.d_i0 = pow(2.0, -31) * subp->sub3.i0;
subp->sub3.Crc = (int16_t)((words[6] >> 8) & 0x00FFFF);
subp->sub3.d_Crc = pow(2.0, -5) * subp->sub3.Crc;
subp->sub3.omega = (int32_t)(words[6] & 0x0000FF);
subp->sub3.omega <<= 24;
subp->sub3.omega |= ( words[7] & 0x00FFFFFF);
subp->sub3.d_omega = pow(2.0, -31) * subp->sub3.omega;
subp->sub3.Omegad = (int32_t)(words[8] & 0x00FFFFFF);
subp->sub3.Omegad = uint2int(subp->sub3.Omegad, 24);
subp->sub3.d_Omegad = pow(2.0, -43) * subp->sub3.Omegad;
subp->sub3.IODE = ((words[9] >> 16) & 0x0000FF);
subp->sub3.IDOT = (int16_t)((words[9] >> 2) & 0x003FFF);
subp->sub3.IDOT = uint2int(subp->sub3.IDOT, 14);
subp->sub3.d_IDOT = pow(2.0, -43) * subp->sub3.IDOT;
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:3 SV:%2u IODE:%3u I IDOT:%.6g Cic:%.6e Omega0:%.11e "
" Cis:%.7g i0:%.11e Crc:%.7g omega:%.11e Omegad:%.6e\n",
subp->tSVID, subp->sub3.IODE, subp->sub3.d_IDOT,
subp->sub3.d_Cic, subp->sub3.d_Omega0, subp->sub3.d_Cis,
subp->sub3.d_i0, subp->sub3.d_Crc, subp->sub3.d_omega,
subp->sub3.d_Omegad );
break;
case 4:
{
int i = 0; /* handy loop counter */
int sv = -2;
switch (subp->pageid) {
case 0:
/* almanac for dummy sat 0, which is same as transmitting sat */
sv = 0;
break;
case 1:
case 6:
case 11:
case 16:
case 21:
case 57:
/* for some inscutable reason these pages are all sent
* as page 57, IS-GPS-200E Table 20-V */
break;
case 12:
case 24:
case 62:
/* for some inscrutable reason these pages are all sent
* as page 62, IS-GPS-200E Table 20-V */
break;
case 14:
case 53:
/* for some inscrutable reason page 14 is sent
* as page 53, IS-GPS-200E Table 20-V */
break;
case 15:
case 54:
/* for some inscrutable reason page 15 is sent
* as page 54, IS-GPS-200E Table 20-V */
break;
case 19:
/* for some inscrutable reason page 20 is sent
* as page 58, IS-GPS-200E Table 20-V */
/* reserved page */
break;
case 20:
/* for some inscrutable reason page 20 is sent
* as page 59, IS-GPS-200E Table 20-V */
/* reserved page */
break;
case 22:
case 60:
/* for some inscrutable reason page 22 is sent
* as page 60, IS-GPS-200E Table 20-V */
/* reserved page */
break;
case 23:
case 61:
/* for some inscrutable reason page 23 is sent
* as page 61, IS-GPS-200E Table 20-V */
/* reserved page */
break;
/* almanac data for SV 25 through 32 respectively; */
case 2:
sv = 25;
break;
case 3:
sv = 26;
break;
case 4:
sv = 27;
break;
case 5:
sv = 28;
break;
case 7:
sv = 29;
break;
case 8:
sv = 30;
break;
case 9:
sv = 31;
break;
case 10:
sv = 32;
break;
case 13:
case 52:
/* NMCT */
sv = -1;
subp->sub4_13.ai = (unsigned char)((words[2] >> 22) & 0x000003);
/*@+charint@*/
subp->sub4_13.ERD[1] = (char)((words[2] >> 8) & 0x00003F);
subp->sub4_13.ERD[2] = (char)((words[2] >> 2) & 0x00003F);
subp->sub4_13.ERD[3] = (char)((words[2] >> 0) & 0x000003);
subp->sub4_13.ERD[3] <<= 2;
subp->sub4_13.ERD[3] |= (char)((words[3] >> 20) & 0x00000F);
subp->sub4_13.ERD[4] = (char)((words[3] >> 14) & 0x00003F);
subp->sub4_13.ERD[5] = (char)((words[3] >> 8) & 0x00003F);
subp->sub4_13.ERD[6] = (char)((words[3] >> 2) & 0x00003F);
subp->sub4_13.ERD[7] = (char)((words[3] >> 0) & 0x000003);
subp->sub4_13.ERD[7] <<= 2;
subp->sub4_13.ERD[7] |= (char)((words[4] >> 20) & 0x00000F);
subp->sub4_13.ERD[8] = (char)((words[4] >> 14) & 0x00003F);
subp->sub4_13.ERD[9] = (char)((words[4] >> 8) & 0x00003F);
subp->sub4_13.ERD[10] = (char)((words[4] >> 2) & 0x00003F);
subp->sub4_13.ERD[11] = (char)((words[4] >> 0) & 0x00000F);
subp->sub4_13.ERD[11] <<= 2;
subp->sub4_13.ERD[11] |= (char)((words[5] >> 20) & 0x00000F);
subp->sub4_13.ERD[12] = (char)((words[5] >> 14) & 0x00003F);
subp->sub4_13.ERD[13] = (char)((words[5] >> 8) & 0x00003F);
subp->sub4_13.ERD[14] = (char)((words[5] >> 2) & 0x00003F);
subp->sub4_13.ERD[15] = (char)((words[5] >> 0) & 0x000003);
subp->sub4_13.ERD[15] <<= 2;
subp->sub4_13.ERD[15] |= (char)((words[6] >> 20) & 0x00000F);
subp->sub4_13.ERD[16] = (char)((words[6] >> 14) & 0x00003F);
subp->sub4_13.ERD[17] = (char)((words[6] >> 8) & 0x00003F);
subp->sub4_13.ERD[18] = (char)((words[6] >> 2) & 0x00003F);
subp->sub4_13.ERD[19] = (char)((words[6] >> 0) & 0x000003);
subp->sub4_13.ERD[19] <<= 2;
subp->sub4_13.ERD[19] |= (char)((words[7] >> 20) & 0x00000F);
subp->sub4_13.ERD[20] = (char)((words[7] >> 14) & 0x00003F);
subp->sub4_13.ERD[21] = (char)((words[7] >> 8) & 0x00003F);
subp->sub4_13.ERD[22] = (char)((words[7] >> 2) & 0x00003F);
subp->sub4_13.ERD[23] = (char)((words[7] >> 0) & 0x000003);
subp->sub4_13.ERD[23] <<= 2;
subp->sub4_13.ERD[23] |= (char)((words[8] >> 20) & 0x00000F);
subp->sub4_13.ERD[24] = (char)((words[8] >> 14) & 0x00003F);
subp->sub4_13.ERD[25] = (char)((words[8] >> 8) & 0x00003F);
subp->sub4_13.ERD[26] = (char)((words[8] >> 2) & 0x00003F);
subp->sub4_13.ERD[27] = (char)((words[8] >> 0) & 0x000003);
subp->sub4_13.ERD[27] <<= 2;
subp->sub4_13.ERD[27] |= (char)((words[9] >> 20) & 0x00000F);
subp->sub4_13.ERD[28] = (char)((words[9] >> 14) & 0x00003F);
subp->sub4_13.ERD[29] = (char)((words[9] >> 8) & 0x00003F);
subp->sub4_13.ERD[30] = (char)((words[9] >> 2) & 0x00003F);
for ( i = 1; i < 31; i++ ) {
subp->sub4_13.ERD[i] = uint2int(subp->sub4_13.ERD[i], 6);
}
/*@-charint@*/
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:4-13 data_id %d ai:%u "
"ERD1:%d ERD2:%d ERD3:%d ERD4:%d "
"ERD5:%d ERD6:%d ERD7:%d ERD8:%d "
"ERD9:%d ERD10:%d ERD11:%d ERD12:%d "
"ERD13:%d ERD14:%d ERD15:%d ERD16:%d "
"ERD17:%d ERD18:%d ERD19:%d ERD20:%d "
"ERD21:%d ERD22:%d ERD23:%d ERD24:%d "
"ERD25:%d ERD26:%d ERD27:%d ERD28:%d "
"ERD29:%d ERD30:%d\n",
subp->data_id, subp->sub4_13.ai,
subp->sub4_13.ERD[1], subp->sub4_13.ERD[2],
subp->sub4_13.ERD[3], subp->sub4_13.ERD[4],
subp->sub4_13.ERD[5], subp->sub4_13.ERD[6],
subp->sub4_13.ERD[7], subp->sub4_13.ERD[8],
subp->sub4_13.ERD[9], subp->sub4_13.ERD[10],
subp->sub4_13.ERD[11], subp->sub4_13.ERD[12],
subp->sub4_13.ERD[13], subp->sub4_13.ERD[14],
subp->sub4_13.ERD[15], subp->sub4_13.ERD[16],
subp->sub4_13.ERD[17], subp->sub4_13.ERD[18],
subp->sub4_13.ERD[19], subp->sub4_13.ERD[20],
subp->sub4_13.ERD[21], subp->sub4_13.ERD[22],
subp->sub4_13.ERD[23], subp->sub4_13.ERD[24],
subp->sub4_13.ERD[25], subp->sub4_13.ERD[26],
subp->sub4_13.ERD[27], subp->sub4_13.ERD[28],
subp->sub4_13.ERD[29], subp->sub4_13.ERD[30]);
break;
case 25:
case 63:
/* for some inscrutable reason page 25 is sent
* as page 63, IS-GPS-200E Table 20-V */
/* A-S flags/SV configurations for 32 SVs,
* plus SV health for SV 25 through 32
*/
sv = -1;
subp->sub4_25.svf[1] = (unsigned char)((words[2] >> 12) & 0x0F);
subp->sub4_25.svf[2] = (unsigned char)((words[2] >> 8) & 0x0F);
subp->sub4_25.svf[3] = (unsigned char)((words[2] >> 4) & 0x0F);
subp->sub4_25.svf[4] = (unsigned char)((words[2] >> 0) & 0x0F);
subp->sub4_25.svf[5] = (unsigned char)((words[3] >> 20) & 0x0F);
subp->sub4_25.svf[6] = (unsigned char)((words[3] >> 16) & 0x0F);
subp->sub4_25.svf[7] = (unsigned char)((words[3] >> 12) & 0x0F);
subp->sub4_25.svf[8] = (unsigned char)((words[3] >> 8) & 0x0F);
subp->sub4_25.svf[9] = (unsigned char)((words[3] >> 4) & 0x0F);
subp->sub4_25.svf[10] = (unsigned char)((words[3] >> 0) & 0x0F);
subp->sub4_25.svf[11] = (unsigned char)((words[4] >> 20) & 0x0F);
subp->sub4_25.svf[12] = (unsigned char)((words[4] >> 16) & 0x0F);
subp->sub4_25.svf[13] = (unsigned char)((words[4] >> 12) & 0x0F);
subp->sub4_25.svf[14] = (unsigned char)((words[4] >> 8) & 0x0F);
subp->sub4_25.svf[15] = (unsigned char)((words[4] >> 4) & 0x0F);
subp->sub4_25.svf[16] = (unsigned char)((words[4] >> 0) & 0x0F);
subp->sub4_25.svf[17] = (unsigned char)((words[5] >> 20) & 0x0F);
subp->sub4_25.svf[18] = (unsigned char)((words[5] >> 16) & 0x0F);
subp->sub4_25.svf[19] = (unsigned char)((words[5] >> 12) & 0x0F);
subp->sub4_25.svf[20] = (unsigned char)((words[5] >> 8) & 0x0F);
subp->sub4_25.svf[21] = (unsigned char)((words[5] >> 4) & 0x0F);
subp->sub4_25.svf[22] = (unsigned char)((words[5] >> 0) & 0x0F);
subp->sub4_25.svf[23] = (unsigned char)((words[6] >> 20) & 0x0F);
subp->sub4_25.svf[24] = (unsigned char)((words[6] >> 16) & 0x0F);
subp->sub4_25.svf[25] = (unsigned char)((words[6] >> 12) & 0x0F);
subp->sub4_25.svf[26] = (unsigned char)((words[6] >> 8) & 0x0F);
subp->sub4_25.svf[27] = (unsigned char)((words[6] >> 4) & 0x0F);
subp->sub4_25.svf[28] = (unsigned char)((words[6] >> 0) & 0x0F);
subp->sub4_25.svf[29] = (unsigned char)((words[7] >> 20) & 0x0F);
subp->sub4_25.svf[30] = (unsigned char)((words[7] >> 16) & 0x0F);
subp->sub4_25.svf[31] = (unsigned char)((words[7] >> 12) & 0x0F);
subp->sub4_25.svf[32] = (unsigned char)((words[7] >> 8) & 0x0F);
subp->sub4_25.svhx[0] = ((words[7] >> 0) & 0x00003F);
subp->sub4_25.svhx[1] = ((words[8] >> 18) & 0x00003F);
subp->sub4_25.svhx[2] = ((words[8] >> 12) & 0x00003F);
subp->sub4_25.svhx[3] = ((words[8] >> 6) & 0x00003F);
subp->sub4_25.svhx[4] = ((words[8] >> 0) & 0x00003F);
subp->sub4_25.svhx[5] = ((words[9] >> 18) & 0x00003F);
subp->sub4_25.svhx[6] = ((words[9] >> 12) & 0x00003F);
subp->sub4_25.svhx[7] = ((words[9] >> 6) & 0x00003F);
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:4-25 data_id %d "
"SV1:%u SV2:%u SV3:%u SV4:%u "
"SV5:%u SV6:%u SV7:%u SV8:%u "
"SV9:%u SV10:%u SV11:%u SV12:%u "
"SV13:%u SV14:%u SV15:%u SV16:%u "
"SV17:%u SV18:%u SV19:%u SV20:%u "
"SV21:%u SV22:%u SV23:%u SV24:%u "
"SV25:%u SV26:%u SV27:%u SV28:%u "
"SV29:%u SV30:%u SV31:%u SV32:%u "
"SVH25:%u SVH26:%u SVH27:%u SVH28:%u "
"SVH29:%u SVH30:%u SVH31:%u SVH32:%u\n",
subp->data_id,
subp->sub4_25.svf[1], subp->sub4_25.svf[2],
subp->sub4_25.svf[3], subp->sub4_25.svf[4],
subp->sub4_25.svf[5], subp->sub4_25.svf[6],
subp->sub4_25.svf[7], subp->sub4_25.svf[8],
subp->sub4_25.svf[9], subp->sub4_25.svf[10],
subp->sub4_25.svf[11], subp->sub4_25.svf[12],
subp->sub4_25.svf[13], subp->sub4_25.svf[14],
subp->sub4_25.svf[15], subp->sub4_25.svf[16],
subp->sub4_25.svf[17], subp->sub4_25.svf[18],
subp->sub4_25.svf[19], subp->sub4_25.svf[20],
subp->sub4_25.svf[21], subp->sub4_25.svf[22],
subp->sub4_25.svf[23], subp->sub4_25.svf[24],
subp->sub4_25.svf[25], subp->sub4_25.svf[26],
subp->sub4_25.svf[27], subp->sub4_25.svf[28],
subp->sub4_25.svf[29], subp->sub4_25.svf[30],
subp->sub4_25.svf[31], subp->sub4_25.svf[32],
subp->sub4_25.svhx[0], subp->sub4_25.svhx[1],
subp->sub4_25.svhx[2], subp->sub4_25.svhx[3],
subp->sub4_25.svhx[4], subp->sub4_25.svhx[5],
subp->sub4_25.svhx[6], subp->sub4_25.svhx[7]);
break;
case 33:
case 34:
case 35:
case 36:
case 37:
case 38:
case 39:
case 40:
case 41:
case 42:
case 43:
case 44:
case 45:
case 46:
case 47:
case 48:
case 49:
case 50:
/* unassigned */
break;
case 51:
/* unknown */
break;
case 17:
case 55:
/* for some inscrutable reason page 17 is sent
* as page 55, IS-GPS-200E Table 20-V */
sv = -1;
/*
* "The requisite 176 bits shall occupy bits 9 through 24
* of word TWO, the 24 MSBs of words THREE through EIGHT,
* plus the 16 MSBs of word NINE." (word numbers changed
* to account for zero-indexing)
* Since we've already stripped the low six parity bits,
* and shifted the data to a byte boundary, we can just
* copy it out. */
/*@ -type @*/
i = 0;
subp->sub4_17.str[i++] = (words[2] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[2]) & 0xff;
subp->sub4_17.str[i++] = (words[3] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[3] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[3]) & 0xff;
subp->sub4_17.str[i++] = (words[4] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[4] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[4]) & 0xff;
subp->sub4_17.str[i++] = (words[5] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[5] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[5]) & 0xff;
subp->sub4_17.str[i++] = (words[6] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[6] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[6]) & 0xff;
subp->sub4_17.str[i++] = (words[7] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[7] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[7]) & 0xff;
subp->sub4_17.str[i++] = (words[8] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[8] >> 8) & 0xff;
subp->sub4_17.str[i++] = (words[8]) & 0xff;
subp->sub4_17.str[i++] = (words[9] >> 16) & 0xff;
subp->sub4_17.str[i++] = (words[9] >> 8) & 0xff;
subp->sub4_17.str[i] = '\0';
/*@ +type @*/
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:4-17 system message: %.24s\n",
subp->sub4_17.str);
break;
case 18:
case 56:
/* for some inscrutable reason page 18 is sent
* as page 56, IS-GPS-200E Table 20-V */
/* ionospheric and UTC data */
sv = -1;
/* current leap seconds */
subp->sub4_18.alpha0 = (int8_t)((words[2] >> 8) & 0x0000FF);
subp->sub4_18.d_alpha0 = pow(2.0, -30) * (int)subp->sub4_18.alpha0;
subp->sub4_18.alpha1 = (int8_t)((words[2] >> 0) & 0x0000FF);
subp->sub4_18.d_alpha1 = pow(2.0, -27) * (int)subp->sub4_18.alpha1;
subp->sub4_18.alpha2 = (int8_t)((words[3] >> 16) & 0x0000FF);
subp->sub4_18.d_alpha2 = pow(2.0, -24) * (int)subp->sub4_18.alpha2;
subp->sub4_18.alpha3 = (int8_t)((words[3] >> 8) & 0x0000FF);
subp->sub4_18.d_alpha3 = pow(2.0, -24) * (int)subp->sub4_18.alpha3;
subp->sub4_18.beta0 = (int8_t)((words[3] >> 0) & 0x0000FF);
subp->sub4_18.d_beta0 = pow(2.0, 11) * (int)subp->sub4_18.beta0;
subp->sub4_18.beta1 = (int8_t)((words[4] >> 16) & 0x0000FF);
subp->sub4_18.d_beta1 = pow(2.0, 14) * (int)subp->sub4_18.beta1;
subp->sub4_18.beta2 = (int8_t)((words[4] >> 8) & 0x0000FF);
subp->sub4_18.d_beta2 = pow(2.0, 16) * (int)subp->sub4_18.beta2;
subp->sub4_18.beta3 = (int8_t)((words[4] >> 0) & 0x0000FF);
subp->sub4_18.d_beta3 = pow(2.0, 16) * (int)subp->sub4_18.beta3;
subp->sub4_18.A1 = (int32_t)((words[5] >> 0) & 0xFFFFFF);
subp->sub4_18.A1 = uint2int(subp->sub4_18.A1, 24);
subp->sub4_18.d_A1 = pow(2.0,-50) * subp->sub4_18.A1;
subp->sub4_18.A0 = (int32_t)((words[6] >> 0) & 0xFFFFFF);
subp->sub4_18.A0 <<= 8;
subp->sub4_18.A0 |= ((words[7] >> 16) & 0x0000FF);
subp->sub4_18.d_A0 = pow(2.0,-30) * subp->sub4_18.A0;
/* careful WN is 10 bits, but WNt is 8 bits! */
/* WNt (Week Number of LSF) */
subp->sub4_18.tot = ((words[7] >> 8) & 0x0000FF);
subp->sub4_18.d_tot = pow(2.0,12) * subp->sub4_18.tot;
subp->sub4_18.WNt = ((words[7] >> 0) & 0x0000FF);
subp->sub4_18.leap = (int8_t)((words[8] >> 16) & 0x0000FF);
subp->sub4_18.WNlsf = ((words[8] >> 8) & 0x0000FF);
/* DN (Day Number of LSF) */
subp->sub4_18.DN = (words[8] & 0x0000FF);
/* leap second future */
subp->sub4_18.lsf = (int8_t)((words[9] >> 16) & 0x0000FF);
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:4-18 a0:%.5g a1:%.5g a2:%.5g a3:%.5g "
"b0:%.5g b1:%.5g b2:%.5g b3:%.5g "
"A1:%.11e A0:%.11e tot:%.5g WNt:%u "
"ls: %d WNlsf:%u DN:%u, lsf:%d\n",
subp->sub4_18.d_alpha0, subp->sub4_18.d_alpha1,
subp->sub4_18.d_alpha2, subp->sub4_18.d_alpha3,
subp->sub4_18.d_beta0, subp->sub4_18.d_beta1,
subp->sub4_18.d_beta2, subp->sub4_18.d_beta3,
subp->sub4_18.d_A1, subp->sub4_18.d_A0,
subp->sub4_18.d_tot, subp->sub4_18.WNt,
subp->sub4_18.leap, subp->sub4_18.WNlsf,
subp->sub4_18.DN, subp->sub4_18.lsf);
#ifdef TIMEHINT_ENABLE
/* IS-GPS-200 Revision E, paragraph 20.3.3.5.2.4 */
if (((session->context->gps_week % 256) == (unsigned short)subp->sub4_18.WNlsf) &&
/* notify the leap seconds correction in the end of current day */
((double)((subp->sub4_18.DN - 1) * SECS_PER_DAY) < session->context->gps_tow) &&
((double)(subp->sub4_18.DN * SECS_PER_DAY) > session->context->gps_tow)) {
if ( subp->sub4_18.leap < subp->sub4_18.lsf )
session->context->leap_notify = LEAP_ADDSECOND;
else if ( subp->sub4_18.leap > subp->sub4_18.lsf )
session->context->leap_notify = LEAP_DELSECOND;
else
session->context->leap_notify = LEAP_NOWARNING;
} else
session->context->leap_notify = LEAP_NOWARNING;
#endif /* TIMEHINT_ENABLE */
session->context->leap_seconds = (int)subp->sub4_18.leap;
session->context->valid |= LEAP_SECOND_VALID;
break;
default:
; /* no op */
}
if ( -1 < sv ) {
subp->is_almanac = 1;
subframe_almanac(subp->tSVID, words, subp->subframe_num,
(uint8_t)sv, subp->data_id,
&subp->sub4.almanac,
session->context->debug);
} else if ( -2 == sv ) {
/* unknown or secret page */
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:4-%d data_id %d\n",
subp->pageid, subp->data_id);
return 0;
}
/* else, already handled */
}
break;
case 5:
/* Pages 0, dummy almanac for dummy SV 0
* Pages 1 through 24: almanac data for SV 1 through 24
* Page 25: SV health data for SV 1 through 24, the almanac
* reference time, the almanac reference week number.
*/
if ( 25 > subp->pageid ) {
subp->is_almanac = 1;
subframe_almanac(subp->tSVID, words, subp->subframe_num,
subp->pageid, subp->data_id, &subp->sub5.almanac,
session->context->debug);
} else if ( 51 == subp->pageid ) {
/* for some inscrutable reason page 25 is sent as page 51
* IS-GPS-200E Table 20-V */
subp->sub5_25.toa = ((words[2] >> 8) & 0x0000FF);
subp->sub5_25.l_toa <<= 12;
subp->sub5_25.WNa = ( words[2] & 0x0000FF);
subp->sub5_25.sv[1] = ((words[2] >> 18) & 0x00003F);
subp->sub5_25.sv[2] = ((words[2] >> 12) & 0x00003F);
subp->sub5_25.sv[3] = ((words[2] >> 6) & 0x00003F);
subp->sub5_25.sv[4] = ((words[2] >> 0) & 0x00003F);
subp->sub5_25.sv[5] = ((words[3] >> 18) & 0x00003F);
subp->sub5_25.sv[6] = ((words[3] >> 12) & 0x00003F);
subp->sub5_25.sv[7] = ((words[3] >> 6) & 0x00003F);
subp->sub5_25.sv[8] = ((words[3] >> 0) & 0x00003F);
subp->sub5_25.sv[9] = ((words[4] >> 18) & 0x00003F);
subp->sub5_25.sv[10] = ((words[4] >> 12) & 0x00003F);
subp->sub5_25.sv[11] = ((words[4] >> 6) & 0x00003F);
subp->sub5_25.sv[12] = ((words[4] >> 0) & 0x00003F);
subp->sub5_25.sv[13] = ((words[5] >> 18) & 0x00003F);
subp->sub5_25.sv[14] = ((words[5] >> 12) & 0x00003F);
subp->sub5_25.sv[15] = ((words[5] >> 6) & 0x00003F);
subp->sub5_25.sv[16] = ((words[5] >> 0) & 0x00003F);
subp->sub5_25.sv[17] = ((words[6] >> 18) & 0x00003F);
subp->sub5_25.sv[18] = ((words[6] >> 12) & 0x00003F);
subp->sub5_25.sv[19] = ((words[6] >> 6) & 0x00003F);
subp->sub5_25.sv[20] = ((words[6] >> 0) & 0x00003F);
subp->sub5_25.sv[21] = ((words[7] >> 18) & 0x00003F);
subp->sub5_25.sv[22] = ((words[7] >> 12) & 0x00003F);
subp->sub5_25.sv[23] = ((words[7] >> 6) & 0x00003F);
subp->sub5_25.sv[24] = ((words[7] >> 0) & 0x00003F);
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:5-25 SV:%2u ID:%u toa:%lu WNa:%u "
"SV1:%u SV2:%u SV3:%u SV4:%u "
"SV5:%u SV6:%u SV7:%u SV8:%u "
"SV9:%u SV10:%u SV11:%u SV12:%u "
"SV13:%u SV14:%u SV15:%u SV16:%u "
"SV17:%u SV18:%u SV19:%u SV20:%u "
"SV21:%u SV22:%u SV23:%u SV24:%u\n",
subp->tSVID, subp->data_id,
subp->sub5_25.l_toa, subp->sub5_25.WNa,
subp->sub5_25.sv[1], subp->sub5_25.sv[2],
subp->sub5_25.sv[3], subp->sub5_25.sv[4],
subp->sub5_25.sv[5], subp->sub5_25.sv[6],
subp->sub5_25.sv[7], subp->sub5_25.sv[8],
subp->sub5_25.sv[9], subp->sub5_25.sv[10],
subp->sub5_25.sv[11], subp->sub5_25.sv[12],
subp->sub5_25.sv[13], subp->sub5_25.sv[14],
subp->sub5_25.sv[15], subp->sub5_25.sv[16],
subp->sub5_25.sv[17], subp->sub5_25.sv[18],
subp->sub5_25.sv[19], subp->sub5_25.sv[20],
subp->sub5_25.sv[21], subp->sub5_25.sv[22],
subp->sub5_25.sv[23], subp->sub5_25.sv[24]);
} else {
/* unknown page */
gpsd_report(session->context->debug, LOG_PROG,
"50B: SF:5-%d data_id %d uknown page\n",
subp->pageid, subp->data_id);
return 0;
}
break;
default:
/* unknown/illegal subframe */
return 0;
}
return SUBFRAME_SET;
}
/*@ +usedef @*/
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