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sdk:gps-udp-client-gnsstogps [2019/07/08 13:41] – created fachet | sdk:gps-udp-client-gnsstogps [2021/10/08 10:22] (current) – [SDK Script gps-udp-client-GNSStoGPS.are] dodenhoeft | ||
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+ | ====== Background ====== | ||
+ | GPS was the first Global Navigation Satellite System (GNSS) and the term GPS is often used as a synonym for GNSS. | ||
+ | |||
+ | Older software often only checks for NMEA 0183 sentences starting with < | ||
+ | |||
+ | Newer GNSS receivers often use multiple GNSS systems and therefore < | ||
+ | |||
+ | It would be better to us instead of < | ||
+ | |||
+ | < | ||
+ | NMEA 0183 sentence " | ||
+ | |||
+ | " | ||
+ | " | ||
+ | BD = Beidu | ||
+ | GA = Galileo | ||
+ | GL = GLONASS | ||
+ | GP = GPS | ||
+ | GN = GNSS position fix from more than one constellation (eg. GPS + GLONASS) | ||
+ | " | ||
+ | RMC = Recommended Minimum Sentence C (used in most cases) | ||
+ | GGA = Global Positioning System Fix Data | ||
+ | GNS = GNSS fixed data | ||
+ | GLL = Geographic Position - Latitude/ | ||
+ | ... | ||
+ | |||
+ | Source: https:// | ||
+ | </ | ||
+ | |||
====== SDK Script gps-udp-client-GNSStoGPS.are ====== | ====== SDK Script gps-udp-client-GNSStoGPS.are ====== | ||
- | <code c gps-udp-client-gnstogps.are> | + | <code c gps-udp-client-gnsstogps.are> |
/* DESC: This script sends the local GPS NMEA stream to a remote UDP server. | /* DESC: This script sends the local GPS NMEA stream to a remote UDP server. | ||
* DESC: It checks for the correct CR/LF end of line characters and convert messages $GN to $GP | * DESC: It checks for the correct CR/LF end of line characters and convert messages $GN to $GP | ||
Line 7: | Line 36: | ||
/* default values */ | /* default values */ | ||
- | server_ip | + | local_ip |
- | server_port | + | local_port |
gpsd = -1; | gpsd = -1; | ||
Line 23: | Line 52: | ||
nb_config_set(" | nb_config_set(" | ||
- | sleep(3); | + | do { |
+ | | ||
+ | } while ( nb_config_done() != 0) | ||
+ | |||
nb_config_set(" | nb_config_set(" | ||
- | sleep(5); | + | do { |
+ | | ||
+ | } while ( nb_config_done() != 0) | ||
return 0; | return 0; | ||
} | } | ||
- | |||
int gpsd_connect () | int gpsd_connect () | ||
{ | { | ||
Line 39: | Line 71: | ||
exit(-1); | exit(-1); | ||
} | } | ||
- | for (attempt = 0; attempt <= 5; attempt++) { | + | for (attempt = 0; attempt <= 15; attempt++) { |
- | sleep(3); | + | sleep(15); |
- | if (connect(gpsd, | + | if (connect(gpsd, |
nb_syslog(" | nb_syslog(" | ||
- | + | if (attempt == 12) { | |
- | if (attempt == 3) { | + | |
nb_syslog(" | nb_syslog(" | ||
gpsd_restart(); | gpsd_restart(); | ||
Line 54: | Line 85: | ||
} | } | ||
nb_syslog(" | nb_syslog(" | ||
- | send(gpsd," | + | send(gpsd, " |
nb_syslog(" | nb_syslog(" | ||
return gpsd; | return gpsd; | ||
+ | } | ||
+ | |||
+ | string checksum(string s) | ||
+ | { | ||
+ | pos = strchr(s, " | ||
+ | |||
+ | if (is_void(pos)) | ||
+ | return s; /* no checksum to correct */ | ||
+ | |||
+ | cs = 0; | ||
+ | chars = explode(s); | ||
+ | for (i = 1; i < pos; i++) { /* skip $ and *XX */ | ||
+ | c = ord(chars[i]); | ||
+ | cs ^= c; | ||
+ | } | ||
+ | r = sprintf(" | ||
+ | return r; | ||
} | } | ||
/* main() */ | /* main() */ | ||
- | if(argc | + | if (argc < 2) { |
- | server_ip = trim((string) argv[1]); | + | usage(); |
- | } | + | |
- | if(argc > 1) { | + | |
- | server_port = (int) argv[2]; | + | |
- | } | + | |
- | if(argc > 2) { | + | |
- | usage(); | + | |
} | } | ||
+ | |||
+ | SERVER = trim((string) argv[1]); | ||
+ | PORT = (int) argv[2]; | ||
/* open UDP server socket */ | /* open UDP server socket */ | ||
server = socket(AF_INET, | server = socket(AF_INET, | ||
- | if(server < 0) { | + | if (server < 0) { |
nb_syslog(" | nb_syslog(" | ||
exit(-1); | exit(-1); | ||
Line 109: | Line 154: | ||
data = recv(gpsd); | data = recv(gpsd); | ||
len = strlen(data); | len = strlen(data); | ||
- | |||
/* Check for correct framing: CR+LF */ | /* Check for correct framing: CR+LF */ | ||
if(len > 2) { | if(len > 2) { | ||
Line 128: | Line 172: | ||
} | } | ||
/* Convert message $GN to $GP for backward compatibility */ | /* Convert message $GN to $GP for backward compatibility */ | ||
- | if(strstr(data," | + | if(strstr(data, |
a_arr = explode(data); | a_arr = explode(data); | ||
a_arr[2] = " | a_arr[2] = " | ||
- | data = implode(a_arr); | + | data = checksum(implode(a_arr)); |
} | } | ||
- | |||
/* skip all messages different from GPGGA | /* skip all messages different from GPGGA | ||
* if(strstr(data," | * if(strstr(data," | ||
Line 150: | Line 193: | ||
close(server); | close(server); | ||
} | } | ||
- | exit(-1); | + | exit(-1);</ |
- | + | ||
- | </ | + | |