From 7d2c2144f169043e95bf8d1d4283d84f9daade82 Mon Sep 17 00:00:00 2001
From: Tim Everett <tim.everett3@gmail.com>
Date: Wed, 18 Dec 2019 10:48:25 -0700
Subject: [PATCH] - Add ublox receiver option to adjust carrier phase quality
threshold for valid measurement - Increase default valid carrier phase
threshold from 5 to 7
---
src/rcv/ublox.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/src/rcv/ublox.c b/src/rcv/ublox.c
index 6724710..9b758f9 100644
--- a/src/rcv/ublox.c
+++ b/src/rcv/ublox.c
@@ -100,7 +100,8 @@ typedef enum { false, true } bool;
#define P2_10 0.0009765625 /* 2^-10 */
-#define CPSTD_VALID 5 /* std-dev threshold of carrier-phase valid */
+#define MAX_CPSTD_VALID 7 /* max std-dev for valid carrier-phase */
+#define CPSTD_SLIP 15 /* std-dev threshold for slip */
#define ROUND(x) (int)floor((x)+0.5)
@@ -334,7 +335,7 @@ static int decode_rxmrawx(raw_t *raw)
unsigned char *p=raw->buff+6;
char *q,tstr[64];
double tow,P,L,D,tn,tadj=0.0,toff=0.0;
- int i,j,k,f,sys,prn,sat,code,slip,halfv,halfc,LLI,n=0,std_slip=0;
+ int i,j,k,f,sys,prn,sat,code,slip,halfv,halfc,LLI,n=0,cpstd_valid,cpstd_slip;
int week,nmeas,ver,gnss,svid,sigid,frqid,lockt,cn0,cpstd,prstd,tstat;
trace(4,"decode_rxmrawx: len=%d\n",raw->len);
@@ -367,10 +368,15 @@ static int decode_rxmrawx(raw_t *raw)
if ((q=strstr(raw->opt,"-TADJ="))) {
sscanf(q,"-TADJ=%lf",&tadj);
}
+ /* max valid std-dev of carrier-phase (-MAX_STD_CP) */
+ if ((q=strstr(raw->opt,"-MAX_STD_CP="))) {
+ sscanf(q,"-MAX_STD_CP=%d",&cpstd_valid);
+ } else cpstd_valid=MAX_CPSTD_VALID;
/* slip threshold of std-dev of carrier-phase (-STD_SLIP) */
if ((q=strstr(raw->opt,"-STD_SLIP="))) {
- sscanf(q,"-STD_SLIP=%d",&std_slip);
- }
+ sscanf(q,"-STD_SLIP=%d",&cpstd_slip);
+ } else cpstd_slip=CPSTD_SLIP;
+
/* time tag adjustment */
if (tadj>0.0) {
tn=time2gpst(time,&week)/tadj;
@@ -390,16 +396,15 @@ static int decode_rxmrawx(raw_t *raw)
prstd=U1(p+27)&15; /* pseudorange std-dev */
cpstd=U1(p+28)&15; /* cpStdev (m) */
prstd=1<<(prstd>=5?prstd-5:0); /* prstd=2^(x-5) */
- prstd=prstd<=9?prstd:9; /* limit to 9 to fit RINEX format */
tstat=U1(p+30); /* trkStat */
if (!(tstat&1)) P=0.0;
- if (!(tstat&2)||L==-0.5||cpstd>CPSTD_VALID) L=0.0; /* invalid phase */
+ if (!(tstat&2)||L==-0.5||cpstd>cpstd_valid) L=0.0; /* invalid phase */
if (!(sys=ubx_sys(gnss))) {
trace(2,"ubx rxmrawx: system error gnss=%d\n", gnss);
continue;
}
- prn=svid+(sys==SYS_QZS?192:0);
+ prn=svid+(sys==SYS_QZS?MINPRNQZS-1:0);
if (!(sat=satno(sys,prn))) {
if (sys==SYS_GLO&&prn==255) {
continue; /* suppress warning for unknown glo satellite */
@@ -432,7 +437,7 @@ static int decode_rxmrawx(raw_t *raw)
halfc=tstat&8?1:0; /* half cycle subtracted from phase */
slip=lockt==0||lockt*1E-3<raw->lockt[sat-1][f-1]||
halfc!=raw->halfc[sat-1][f-1];
- if (std_slip>0&&cpstd>=std_slip) slip=LLI_SLIP;
+ if (cpstd>=cpstd_slip) slip=LLI_SLIP;
if (slip) raw->lockflag[sat-1][f-1]=slip;
raw->lockt[sat-1][f-1]=lockt*1E-3;
raw->halfc[sat-1][f-1]=halfc;
@@ -457,9 +462,11 @@ static int decode_rxmrawx(raw_t *raw)
}
n++;
}
+ prstd=prstd<=9?prstd:9; /* limit to 9 to fit RINEX format */
+ cpstd=cpstd<=9?cpstd:9; /* limit to 9 to fit RINEX format */
raw->obs.data[j].L[f-1]=L;
raw->obs.data[j].P[f-1]=P;
- raw->obs.data[j].qualL[f-1]=cpstd<=7?cpstd:0;
+ raw->obs.data[j].qualL[f-1]=cpstd;
raw->obs.data[j].qualP[f-1]=prstd;
raw->obs.data[j].D[f-1]=(float)D;
raw->obs.data[j].SNR[f-1]=(unsigned char)(cn0*4);
@@ -1269,6 +1276,7 @@ static int sync_ubx(unsigned char *buff, unsigned char data)
* -INVCP : invert polarity of carrier-phase
* -TADJ=tint : adjust time tags to multiples of tint (sec)
* -STD_SLIP=std: slip by std-dev of carrier phase under std
+* -MAX_CP_STD=std: max std-dev of carrier phase
* -GALFNAV : input only F/NAV for galileo ephemeris
*
* The supported messages are as follows.
--
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