Questions tagged [gps]
This tag refers generically to *any* space-based satellite navigation system that provides location and time information.
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Converting GPS orthometric heights to height above MLLW
I need convert GPS elevation measurements collected along the coast of California to height above Mean Lower Low Water (MLLW) using NOAA's VDatum tool. The measurements were collected from 2010-2022 ...
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Track two live GPS in QGIS
Does anyone know how to display the output of multiple GPS devices at the same time in QGIS for live-tracking in the field?
I have two GPS devices that are both outputting NMEA sentences through ...
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Is it correct to tilt the pole of a GPS / GNSS antenna to procure the position?
Recently a salesperson from a company that sells GPS / GNSS equipment visited our college to demonstrate the GPS / GNSS device in a differential mode. The salesperson was demonstrating a GNSS antenna ...
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QGIS cannot connect to serial "GPS"
I am working on a larger project with the end goal of streaming GPS data via LoRa to a receiver attached to a computer on COM6 and passing the data via a simulated COM4 through a simulated COM5 to ...
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Edit feature without losing GPS data in QField
I use QField to collect data entered manually in the field. But also internal GNSS data (horizontal and vertical precision).
In the QGIS form I save the default values: @gnss_horizontal_accuracy and @...
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Map-matching on table of geometries
I have a table that represents an OSM map. Each row representes an edge of the graph. It has the following attributes:
road_id,
start_node,
end_node,
direction,
linestring
I want to mapmatch a trace ...
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Decode GPS tracker data format send to the server
I have tried to find any documentation regarding the data received from my GPS tracker. Being a Chinese model I could not find any clue to decode the string send by the GPS tracker.
The format is: ...
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Navigating to a point with cm accuracy
I am due to install some monitoring points for a field experiment. I have a GNSS receiver (Arrow 100) and so can record the location of my monitoring points with a high degree of accuracy. I am ...
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Can GPS live tracking log GPGLL strings in QGIS?
I am using QGIS MaidenHead in the field, with one laptop connected to a serial port GPS for ships location, and one laptop connected via serial port GPS for ‘package’ location underwater. The ships ...
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What's wrong with my pseudo ranges?
I would like to figure out how to calculate pseudoranges from the information I receive in RTCM messages. The relevant fields of RTCM messages, if I understand correctly, are DF397, DF398, DF400. And ...
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Bounding box intersection when crossing date-line and meridian
First of all, I check for general intersections:
public bool CheckOverlap(BoundingBox boundingBox)
{
if (this.UpperRight.Longitude < boundingBox.LowerLeft.Longitude)
return ...
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Connecting GNSS receiver and ArcGIS Field Maps
I have a problem with my GNSS receiver and ArcGIS Field Maps by Esri. I´m using Stonex S500 receiver with cube application. In this application receiver working perfect. But if I start Field maps and ...
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Bad-Elf With an iPhone: cannot be paired
I am new with using Qfield on my iPhone XR (formerly with Cartomobile). I do try to link the external Bad-Elf GNSS Surveyor in QField using Parameter-Positionning-Add but the Bad-Elf GPS is not ...
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What does "Common frequency offset" plot means in gnss raw measurements?
I'm using Google's MATLAB code to analyze raw gnss measurement made with gnsslogger android app. In plots, there is one in particular that I don't understand the meaning, which is "Common ...
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Why if I spoof the position with GNSS Analysis MATLAB Google code,I get a spike of horizontal speed but it continue to be active while should be const
I'm using this GNSS Analysis Matlab Google code
to analyze the measurements performed via GNSSLogger app.
I was initially in Palermo,Sicily and tried to spoof to Rome. I get this
Horizontal speed ...
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Vertical CRS my Google Earth Engine code is outputting when I export to a CSV
I am using Google Earth Engine to annotate my movement tracks with high resolution elevation data. I am currently importing lat/long coordinates which have a horizontal crs=EPSG:4326. I am annotating ...
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Importing NMEA RMC sentences into QGIS
I would like to import NMEA RMC datasets into QGIS (I'm using 3.28.3-Firenze). I log these on a separate measurement data logger. So far I have been able to import a .log file with GGA and RMC ...
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GPS NMEA - is VTG 'Course' the same as RMC 'Course over ground'?
I have been reading up on NMEA messages here and other places, but it isn't obvious to me if the VTG message 1 (Course) is the same as RMC message 8 (Course over ground). They use the same number for ...
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How to assign a household (with its GPS latitude and coordinate) to a certain pixel of the .tif file in R-Studio
I have a one-day composite flooding data downloaded from https://www.ssec.wisc.edu/flood-map-demo/ftp-link/ftp-link-viirsrealtime/ for a specific region (called viirs_max_01_2023.tif).
The pixels are ...
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Bad Elf not showing location data in QField
We have a K88 Android tablet running version 7.1.1 (currrent version is 14 something). I can connect the Bad Elf to the app via Bluetooth, but no positioning data appears to be transmitted. I've ...
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Connection between GPGGA HDOP and GPGST deviations
I would like some clarification regarding HDOP in the GPGGA message (Field 9) and standard deviation of latitude/longitude error in GPGST message (Fields 7 and 8). Are the values presented in the ...
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Defining outbound and return directions of GPS points in QGIS
In QGIS, I have a layer of points corresponding to the positions of my vehicles every 2 seconds. So, my layer contains the following information:
XY coordinates
Vehicle number
GPS heading
Timestamp
...
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Getting positional data of LEO satellites
How can we get precise lat, long ( or xyz in ECEF ) location of LEO satellite like FORMOSAT (COSMIC-2 ) - including error matrices?
POD data is available here, and tried with ‘Level 1a - Precise orbit ...
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Finding time data in a .gpx file
This seems like a simple problem but I have searched for answers and apparently reached the limit of my experience.
I have a .gpx file and I am trying to see the time data for various points along the ...
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Drawing a polygon from UTM coordinates without using a computer
all.
I'm having trouble remembering how I used to do something, and I can't find any answers so far online. Years ago, I would take various points of, say, a field using a handheld GPS. I would then ...
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Viewing GPS coordinates on Trimble Geoxh 6000 [closed]
I read that the point coordinate system is proprietary.
What software do I need to view the points as gps coordinates and how would I go about doing it?
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Extracting GPS Coordinates for Grid Square Centers
I'm relatively new to GIS, and I'm currently using QGIS version 3.32.3 Lima. I'm encountering some challenges as I don't have a solid foundation in using GIS, so I'm reaching out for your help and ...
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What is the expected Doppler shift of the GPS C/A L1 PRN code duration? [closed]
For the past few months, I have been writing an SDR-based GPS receiver (L1, LNAV, C/A).
Things are going well, and I've managed to calculate a position fix in deep space. After lots of thinking and ...
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GEE - extract temperature data for a large dataset of GPS locations
I'm trying to extract mean temperature data for specific GPS locations across a large latitudinal/longitudinal range). I am using Google Earth Engine (new at this).
To get to the code I'm showing ...
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What is a tenth of a second (WGS 84) in feet? [duplicate]
What is the equivalent of a tenth of a second (WGS 84) in feet? This would be located in northern NM in the US.
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Calculating from GPS time duration of a linestringM within a polygon
I am analyzing trajectories from GPS points, including timestamp (Linestring M).
I need to clip trajectories that cross polygons, and calculate time spent within those polygons.
However, I have 2 ...
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Finding nearest OSM link (road) to GPS points in Python
I have a large dataset (about 50,000,000 rows) of GPS x,y points related to GPS equipped taxis with timestamps and speeds. I also have a shp. of the OSM links and I want to find the nearest link to ...
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Can differences in Datum make a big difference in RTK surveying?
I'm a student studying surveying and analysis. I have gathered coordinates data on the same point via VRS, RTK, and Thingstream's PPP.
It seems like VRS and RTK goes similar, but PPP keeps getting ...
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Do smartphone GPS error vectors cluster around some fixed vector if I use the same satellites over 10 minutes?
Rather than accurate latitude/longitude/elevation data, I need accurate change-in-latitude/longitude/altitude data. If I use the same satellites over a 10 minute time period, then I expect that two ...
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Get Lat,Lon,Elevation, and IMU data for DSLR camera
I am looking for a way to take images from an airplane window, and record lat/lon/elevation and camera roll,pitch,yaw to image exif data.
The purpose for this is to project detected objects in an ...
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Buffer: shape_Area=0
I used the GPX to feature tool to add data points to my map. I draw buffers with a different radius around each point >10 m (some of them overlap). However, the column shape_Area is 0 for all the ...
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Some iterative way to compute heading and GPS projection at the same time?
I have the following situation:
An off-road machine has a GPS antenna that is not at the center of the rear axle (this point is my path-tracking-control point). Let's say it's 3 meters from the rear ...
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Constructing VTEC values out of UNAVCO data
I'm going through the high-frequency UNAVCO RINEX 2.11 files to create atmospheric maps of the total electron content at a particular timestamp over a particular lat/lon range.
I'm looking for ...
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Connecting to GPS
I am running QGIS on a Panasonic CF-20 toughbook. When I run GPS viewer I get satelite connection and it connects via COM 6 at a baud rate of 9600. Within QGIS when in the GPS panel I select serial ...
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Is there a common method for measuring "curviness" of a line?
I have a bunch of GPS tracks in a Postgres+PostGIS database and want to extract a single metric as a measure of turns shown in the data. Some of the GPS targets travel in almost straight lines while ...
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GPS error introduced by tall cliff
I need to capture the coordinates of several points along the bottom of a tall vertical cliff. Standing at the bottom of the cliff only the half of the sky facing away from the cliff is visible. Is ...
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How to calculate GPS offset given azimuth(bearing) angle and slope distance and inclination angle of the object
If there is an object (tree) which gives back the below data measured from a given GPS location:
Azimuth angle
Slope distance to the tree or object
Inclination angle to the tree or object.
How to ...
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Performance of RTK when observed satellites don’t correspond
When a rover receives observations from a base station (e.g. through NTRIP from a CORS network) it can perform RTK to reduce ambiguities in matching observations to get a more accurate fix.
What ...
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When do permanent RTK base stations need to update their advertised ECEF coordinates to account for continental drift?
I have recently setup an L1/L2 RTK base station in the UK, with the data served via rtklib, NTRIP and rtk2go.com. With a matching rover I am getting reliable 10mm fixes with excellent repeatability ...
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GPS capable rangefinder or camera to capture GPS data
I have looked at this link GPS capable rangefinders or cameras that can capture lat / long data from a distance?
I have looked into the LaserTech product information but it seems to me I can't find a ...
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How to convert a .CSV file to a RINEX file for post-processing?
I will preface this by saying i'm not 100% sure this is the right stack exchange to ask this on and i'm completely out of my depths here with the work i'm trying to do but alas i will proceed.
Field ...
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Get altitude over WGS84 ellipsoid from GPS tracking app [closed]
I have been using multiple GPS tracking apps for sailing in my iPhone, such as iSailor, whose output is a KML file that looks like
...
<when>2023-08-16T09:12:51Z&...
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Saving layers with diferent types to a single GPX file
I have the following twos methods to save a vector layer in the project folder
The first one is generic and the second calls the first to save specifically a GPX file
In order to export one group of ...
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Transform TEME TLE derived positions of a GPS satellite to the WGS84 coordinate system for comparison
I am trying to compare TLE derived x,y,z positions of a GPS satellite with those derived from precise GPS ephemerides (NGA). However, I am having some trouble getting the coordinate systems and ...
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Explanation for the GPS “special message” field
In the GPS specification (p124) there is a facility for the satellite to send a “special message”. The content is “at the discretion of Operating Command” but is anyone aware of any statement of how ...
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