Questions tagged [nmea]
National Marine Electronics Association (NMEA) is organisation setting standards of communication between marine navigation devices.
47
questions
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1answer
16 views
Is this GSV sentence valid?
According to the specifications, GSV sentence contains information about satellite. But in this sentence (extracted from my Sierra receiver):
$GPGSV,3,3,11,04,,,,08,04,262,,10,06,151,*75
If I ...
1
vote
1answer
28 views
Nmea protocol: How many sattelites are actually used to get position?
NMEA 0183 Version 4.10 defines that there cannot be more than 12 satllites in GGA message:
Number of satellites used (range: 0-12)
But there can be more active sattellites defined in GSA:
...
2
votes
1answer
102 views
Using Live GPS in QGIS - Speed and quality is not shown
I am using QGIS 3.10 together with a ArdusimpleRTK2B Board based on U-Blox ZED F9P processor and a Windows 10 based tablet computer.
Using a SAPOS correction service and having connected it via gpsd ...
0
votes
1answer
99 views
What epoch does Proj4 for EPSG:4326 assume? NMEA stream provides Lat Lon at measurement epoch
I get a NMEA stream exported from Applanix PosPac in the epoch the measurements took place (2019). These coordinates go into a software, that interprets the NMEA Lat Lon as EPSG:4326 with Proj4 ...
1
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0answers
17 views
Understanding PMTK order
I am a high school student trying to decode a pycom code I was given, and within it I found this:
$PMTK001,353,3,1,1,1,1,0'
I have been searching a lot about this online, and I know that for ...
0
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0answers
78 views
Reading NMEA frames on i2c device?
I have a linux machine which is connected by I2C to a F9P Ublock GNSS device. I need to get the GGA frames and some custom Ublocks frames from I2C, do some calculations and forward them to UDP.
Is ...
1
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0answers
194 views
calculating HRMS using NMEA sentences including GPGGA , GPGSV, GLGSV, QZGSV,QZGSA, GPGSA?
I have NMEA sentences including GPGGA , GPGSV, GLGSV, QZGSV,QZGSA, GPGSA and GNGSA. my goal is to achieve HRMS accuracy meter. produced android devices for special intent gives GP/GN GST nmea message ...
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0answers
192 views
Difficulty in getting QGIS to connect with in-built GPS (COM3 NMEA port)
I have a Motion J3500 rugged tablet which was upgraded last year to run Windows 10.
The tablet has a built-in GPS / broadband module (Gobi Sierra 2000).
I use QGIS (v3.2) on the tablet, with the GPS ...
3
votes
2answers
564 views
Where does the Geoid information in a GPS unit come from?
In the NMEA GGA-message the 11th field is Geoid separation. How does the GPS-unit "know" this separation?
Are GPS units preloaded with an EGM (Earth Gravitational Model)?
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1answer
686 views
Change NMEA output messages from u-blox8-M8 via UDX message?
I have RealTerm terminal emulator connected to my receiver via RS-232 serial, and it is outputing variety of NMEA strings via it's default configuration. Currently, it looks like it is outputing GPGSV,...
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0answers
30 views
Get the current serial protocol config of a TU30-D400 Series GPS
I have an old Jupiter GPS from the TU30-D400 Series
When I put its 7th to the GND, I can force it to use the NMEA Protocol with a 4800 baud rate.
The thing is that GPS is used by a pretty old tide ...
3
votes
2answers
2k views
Postprocessing with NMEA-data if no rinex-data is available
I have an UAV which does not give me the raw sensor data (e.g. rinex or ubx). The only format I get is NMEA. Now I want to know how could I use the NMEA-data to get the highest precision of my ...
0
votes
1answer
830 views
Get satellite lon/lat from NMEA sentence
I am working on a satellite tracking application where I can read NMEA data from file.
Here are the NMEA sentences I have:
$GPRMC,104426.591,A,5920.7019,N,01803.2893,E,0.117980,320.93,141204,,*0F
$...
4
votes
2answers
731 views
GPRMC date field overflow
I'm decoding NMEA GPRMC sentences from a GPS device. The date field format is ddmmyy. So 191194 is 19 November 1994. This makes it impossible to represent years greater than 1999. Has the spec been ...
1
vote
1answer
196 views
From List into ArcPy Feature Class with InsertCursor
I am parsing an NMEA file to be able to import it into an ArcGIS with arcpy. I finalised the parsing part and also created a list with the appropriate form. But if I'm trying to insert the List into ...
2
votes
0answers
417 views
Plotting realtime .nmea files with QGIS 2.18.10
I am working on a project that requires us to track 2 GPS targets, one car and one weather balloon. The realtime GPS tracking of the car via the COM port works great. The decoded data from our weather ...
1
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0answers
163 views
What's this JSON format when generically connecting to Mifi/Jetpack GPS over Wi-Fi (NMEA)?
I just bought a Mifi 4G wifi modem, which Verizon, a US mobile company, has rebranded as a 'Jetpack'.
While playing with the settings, I found that it also has a GPS receiver built into it, and ...
0
votes
1answer
1k views
Convert NMEA to GPX in GPSBabel
I have received NMEA data stored in an excel file. Sample data:
DOS_TXT GPS_WS NMEA D
1530000114 379550,0702 $GPGGA,092550.000,6311.7019,N,01429.1063,E,1,09,0.88,357.2,M,33.6,M,,*6B,5567,5567736,...
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votes
2answers
3k views
Calculating VRMS and HRMS from NMEA data?
I am trying to write code to parse the NMEA strings coming from survey-grade RTK/GNSS receivers. The requirements I have are to calculate the 3DRMS (distance RMS at 97.5% probability), VRMS (vertical ...
1
vote
1answer
1k views
Estimating accuracy from raw NMEA data
I am developing an android app for a usb GPS module of UBLOX. Is there any accuracy information in the raw NMEA data which i can use in my GUI? or do I have to use any algorithm to calculate the ...
0
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1answer
1k views
NMEA sentences-PADCH,PAGCD
I was looking on was NMEA sentences. From which I got a series of know how doubts.
I got to know about the terms like $GPGGA, GPHDT, GPGSV, GPGLL from GPS data. Also I could see many new terms like ...
1
vote
2answers
896 views
What will post-process differentially correct raw Bad-Elf Surveyor U-Blox NMEA/raw UBX?
I have a Bad-Elf Surveyor unit which claims accuracy ~1m when post-processed, but I am at a loss to find software that can differentially correct the raw NMEA/UBX logs that the unit will record. I ...
5
votes
2answers
13k views
Enabling/disabling NMEA sentences on u-Blox gps receiver?
I want to disable the $GPGSV sentences on u-Blox NEO-7M because I have serial buffer overflow on Arduino.
I found in the Receiver Discription p.69 and tried sending this:
$PUBX,40,GSV,0,0,0,0,0,0*59
...
3
votes
1answer
2k views
How can I stream attitude (roll,pitch,yaw) into Google Earth?
I am streaming position data (lat, lon) of an airplane into Google Earth via NMEA 0183 ($GPRMC, $GPGGA sentences) and it works OK (I generate and stream these from my own software). Now I would also ...
0
votes
1answer
749 views
What is the difference $GPRMC and $GPRMCA?
What is the difference between $GPRMC and $GPRMCA strings?
I can find online documentation about $GPRMC strings, however I have a device that sends $GPRMCA strings.
$GPRMC,225446,A,4916.45,N,12311....
2
votes
2answers
3k views
NMEA to CSV with timestamp using gpsbabel
I tried to convert a file in NMEA to csv using gpsbabel,
$ gpsbabel -i nmea -f GPS_20160204_092027.log -o csv -F GPS_20160204_092027.csv
I get a csv file with only latitude and longitude, but was ...
2
votes
1answer
798 views
Time of the gps fix in GPGGA sentence is always rounded
I am using QSTARZ 818XT device for my app.
I am using GPGGA sentences to get the GPS fixes, but I have noticed that timings are always rounded like xxxxxx.000 - for 1Hz GPS frequency and xxxxxx.x00 ...
6
votes
4answers
6k views
Relation between Geoidal separation and antenna altitude in GGA sentence?
I have searched about definitions and relations about geoidal separation and antenna altitude reported in GGA sentence. The more I read the more I am confused.So in a simple manner can anyone explain ...
0
votes
1answer
653 views
NMEA-2000 Message 129540 (“GNSS Sats in View”): SNR field is integer or decimal?
If you're familiar with the older NMEA 0183, there was a "GSV" record for reporting information about GPS satellites in view, including their SNR (signal-to-noise ratio, also known as carrier-to-noise-...
2
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0answers
150 views
Are there methods of filtering gps-data with metadata?
In our project we captured GPS-tracks from a few electric vehicles in the timeframe of a year. In total we captured around 13000000 GPS-points this way. The captured data comes from electric powered ...
1
vote
2answers
2k views
Measuring distance between two coordinate pairs taken from NMEA file?
In order to measure momentary speed, first I need to measure the distance between two pairs of coordinates. That's where my lack of knowledge stops me.
I have example data in NMEA format:
$GPGGA,...
0
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1answer
7k views
How to convert negative NMEA latitude and longitude values ('S' and 'W')?
I'm getting from GPS data in the form of NMEA. There I'm getting positive latitude and longitude values('N' and 'E').
How do I convert the negative latitude and longitude values('S' and 'W') into ...
1
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1answer
2k views
How do I import a NMEA file into QGIS 2.8?
I have some NMEA data recorded in a file - this is not a realtime application. How do I import that into QGIS 2.8?
2
votes
0answers
481 views
Given raw NMEA data, how do you estimate accuracy on-the-fly?
I have streaming NMEA data from a GPS device to my application. One of the sentences includes HDOP. I previously calculated the circular error probable (CEP) for this unit. How can I calculate the ...
4
votes
3answers
6k views
How to extract NMEA outputs from an external bluetooth GPS to an Android device
I am requested to create an Android app that have to connect to an external Bluetooth GPS and read the NMEA output and visualize the location on ad digital map. I am a new comer in this aspect. ...
6
votes
3answers
13k views
What does 'Course Made Good' in NMEA string mean?
I was looking at some GPS data that a client sent me. It has lines like this:
$GPRMC,183123,A,1725.4170,N,07825.4779,E,37.80,297,161214,,
I was looking at http://aprs.gids.nl/nmea/#rmc, which says ...
0
votes
1answer
647 views
Where can I find documentation on the NMEA sentences supported by the Garmin GLO?
I just picked up a Garmin GLO Bluetooth GPS device. Does anyone know where I can find documentation of the NMEA sentences it outputs?
5
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0answers
9k views
Translating hdop, pdop and vdop to metric accuracy from given NMEA strings
How can I translate dilution of precision to a metric unit?
For example: say I got 1.2 in hdop from NMEA sentence of my GPS receiver,
in what should I multiply to get a metric accuracy? Just like the ...
1
vote
1answer
125 views
Latitude & Longitude values from Simple Voyage Data Recorder [SVDR]
I am receiving values in the form of 0113.7276,N,10339.0121,E from a Ship Data Recorder. I am not a GIS/ GPS expert and am unable to decipher what do these values mean, because they are out of range ...
8
votes
1answer
18k views
How can I convert Horizontal dilution of position to a radius of 68% confidence?
I am working at mobile app that uses external GPS module. What I need is to calculate accuracy for the fix from GPGGA command to be able to compare it with my mobile platform's GPS accuracy. Mobile ...
1
vote
1answer
462 views
Determining the Geoid model used by GPS receiver
I have the following NMEA output by Holux M-241 GPS receiver:
$GPGGA,144014.000,2227.0987,N,11410.1382,E,2,6,1.67,32.6,M,-1.3,M,0000,0000*7B
I know that WGS84 height is higher than Geoid height 1.3 ...
5
votes
1answer
12k views
Current time from GPRMC or GPZDA?
In GPRMC there is a time field, called fix time. Can I consider this always the same as value from GPZDA time? Is there any possibility that when GPS device is configured to stream both GPRMC and ...
2
votes
0answers
345 views
Will NMEA support the GNxx string in future?
At the moment there is no problem when using GPS only devices, NMEA string with information about speed, DOP value etc starts with GP.. prefix. But with Glonass included NMEA string has different ...
2
votes
0answers
169 views
How to configure various client applications to display AVL data?
Given x number of GPS units transmitting NMEA formatted strings back to a server (xxx.xxx.xxx.xxx:xxxxx) is there a way to listen in on the traffic and parse NMEA formatted strings for display on a ...
12
votes
3answers
2k views
GPS Tracking by SMS
I have a GPS Tracker which sends the GPRMC string of the NMEA 0183 protocol, at fixed periodicity, to a predefined number as SMS. I am looking for a software which can port these incoming SMS to a COM ...
26
votes
6answers
18k views
How correct is the “Accuracy” value given by GPS devices?
I have a Garmin Forerunner 305 and a Google Nexus One Android phone. From the GPS on both these devices I can get a "Accuracy" value that is usually between 6-20 meters. How much can I trust this ...
8
votes
1answer
3k views
Calculating absolute precision confidence number from Dilution of Precision indicators from GPS receiver
End-user GPS receivers typically show an absolute confidence indication, such as Within 25 Metres, for the calculated position.
I am parsing NMEA data from a GPS unit and wan't to calculate a similar ...
