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sdk:gps-udp-client-gnsstogps [2019/07/09 13:49] fachet |
sdk:gps-udp-client-gnsstogps [2019/11/28 11:23] fachet |
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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 <nowiki>"$GP"</nowiki> (= GPS only) instead of looking for all GNSS systems. | ||
| + | |||
| + | Newer GNSS receivers often use multiple GNSS systems and therefore <nowiki>"$GN"</nowiki> is used (<nowiki>"$GNRMC..."</nowiki>) if it recives a combination of GPS, Galileo and GLONASS signals. | ||
| + | |||
| + | It would be better to us instead of <nowiki>"$GPRMC"</nowiki> either <nowiki>"$G.RMC"</nowiki> ("." = anychar) for using GPS, Galileo and/or GLONASS (GNSS) or even <nowiki>"$..RMC"</nowiki> which means any source. | ||
| + | |||
| + | <code> | ||
| + | NMEA 0183 sentence "$XXYYY..." explanation: | ||
| + | |||
| + | "$" = Start | ||
| + | "XX" = Source device (https://de.wikipedia.org/wiki/NMEA_0183#Ger%C3%A4te-IDs) | ||
| + | BD = Beidu | ||
| + | GA = Galileo | ||
| + | GL = GLONASS | ||
| + | GP = GPS | ||
| + | GN = GNSS(multiple GNSS sources) | ||
| + | "YYY" = Record | ||
| + | RMC = Recommended Minimum Sentence C (used in most cases) | ||
| + | GGA = Global Positioning System Fix Data | ||
| + | GNS = GNSS fixed data | ||
| + | GLL = Geographic Position - Latitude/Longitude | ||
| + | ... | ||
| + | |||
| + | Source: https://de.wikipedia.org/wiki/NMEA_0183 | ||
| + | </code> | ||
| + | |||
| ====== SDK Script gps-udp-client-GNSStoGPS.are ====== | ====== SDK Script gps-udp-client-GNSStoGPS.are ====== | ||
| <code c gps-udp-client-gnsstogps.are> | <code c gps-udp-client-gnsstogps.are> | ||
| Line 70: | Line 99: | ||
| chars = explode(s); | chars = explode(s); | ||
| for (i = 1; i < pos; i++) { /* skip $ and *XX */ | for (i = 1; i < pos; i++) { /* skip $ and *XX */ | ||
| - | printf(" %s ", chars[i]); | + | c = ord(chars[i]); |
| - | c = ord(chars[i]); | + | |
| cs ^= c; | cs ^= c; | ||
| } | } | ||
| Line 144: | Line 172: | ||
| a_arr = explode(data); | a_arr = explode(data); | ||
| a_arr[2] = "P"; | a_arr[2] = "P"; | ||
| - | data = implode(a_arr); | + | data = checksum(implode(a_arr)); |
| } | } | ||
| /* skip all messages different from GPGGA | /* skip all messages different from GPGGA | ||