This tag refers generically to *any* space-based satellite navigation system that provides location and time information.

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5
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303 views

GPS data based track/trip calculation algorithm available?

Currently I'm receiving position data of moving assets every 90 or 120 seconds (depending on the asset). What I'd like to achieve now is to detect standstill and movement phases (tracks/trips) on the ...
4
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83 views

Using R to map matching GPS data?

I have a bunch of vehicles GPS data points, which consist of "timestamp, longitude, latitude, fuel consumption and distance" and the data is OSM (open street map) based. I want to match the data ...
4
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925 views

Microsoft Surface vs. iPad for mapping

I was recently introduced to the Avenza PDF app for iPad and I've been using it in the company I work for to help our field crews find their way around, and record waypoints and tracks. The app takes ...
3
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0answers
146 views

Import GPS SINEX (for velocity analysis) into Sarscape or processing with others software

I try to import GPS snx. into Sarscape 5.2 (use GPS Import tool) and getting error 115) ) gps_type : [sinex] 116) ) generate_kml : [OK] 117) ) generate_shape : [OK] 118) ) ...
3
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94 views

How to measure RTK accuracy of a moving vehicle?

I am currently working with tractors using a RTK enhanced automated steering system. One of the biggest problems is that even RTK can have a inaccuracy of 2cm. This can be too much for some possible ...
3
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218 views

Calculating Distances between coordinates

I have perused through the other questions that are very similar to mine but am still having some trouble. I have 75 coordinates in WGS84 that I brought in from an Excel table. They are now on my ...
3
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199 views

How to determine and send alert SMS for next bus stop in a GPS tracking system?

In my gps tracking system (PHP/MySql) I have got 5 Stops for a vehicle. Whenever the bus reaches stop 1, the passengers at stop 2 should get an SMS alert. And in the same way for the sops followed ...
3
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64 views

what criteria should I consider in buying a pocket GPS

It's my first time making this kind of choices, and I really don't know how to go with a choice or another. I basically know that it should have good durability , a good battery life and good ...
3
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150 views

Ways to measure similarities/congruence of tracks (point features) in ArcGIS

I have a sets of GPS coordinates recorded while tracking different cross country runners. What I would like to do is to compare how similar the tracks of the individual runners are. Is there a test ...
3
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352 views

QGIS: GPS Tracking with improved Altitude

I am preparing for archeological fieldwork in Sudan. I recently came up with RTK equipment and software using RTKlib to export the real time corrected data (cm level) to QGIS via a simulated NMEA ...
3
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410 views

Are there any shapefile-based GPS data recorders?

I am looking for a data recorder that can be programmed to send a serial data request to a field computer and then accept and record an incoming data string and tie it to GPS location and then save ...
2
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37 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 ...
2
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35 views

Find gravity normal by ECEF or GPS coordinate of point

How to find gravity normal by ECEF or GPS coordinate of point? Is it the same as normal to elipsoid? Is this ordinary way to calculate normal to ellipse? I'm not quite sure which altitude is ...
2
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20 views

Why time differs between gps and ntp exactly 90 seconds

EDIT: This question can be closed due to figured out the problem was in the NTP configuration. While the gps device is no gps data received, gps device is send gps time to server as zeros ...
2
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0answers
54 views

High-level method for offline future road elevation data

I am new to GIS, so please do not hesitate to call me out in providing limited information. I have a .tiff Terrain (elevation) data file for the east coast of the US and a .osm.pbf OSM file for ...
2
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0answers
79 views

Reaching cm (inch) level elevation precision using drones

A road construction firm needs altitude data of road path before and after the construction and the error should be less than 3 cm (2 inch). Normally, they put a ground station and workers manually ...
2
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33 views

Capturing GPS coords in EXIF header for JPEGs with ArcPad ImageBox control?

Problem with capturing GPS locations in EXIF header for JPEG photo using Esri's ArcPad and its ImageBox control. I have customized forms for ArcPad. I have added three ImageBox controls to a form ...
2
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0answers
41 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 ...
2
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48 views

Understanding Latitude Jumps

I'm decoding some AIS messages and outputting KML files showing routes. Looking at some ships in the Adriatic Sea there are some weird Latitude jumps that I don't understand. Several ships show ...
2
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203 views

Good GPS navigation app for iPhone with downloadable OFFLINE maps?

I am looking for a good GPS navigation app for my iPhone that will work away from wifi and cell coverage (GPS only) and thus allow me to download offline maps. Paid app is OK. Must Have features: ...
2
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43 views

Trimble pathfinder data dictionary default value exclusion

Is it possible to have a numeric attribute in trimble pathfinder without having to use a default value? I am trying to make a numeric attribute compulsory to fill in BUT because the data dictionary ...
2
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0answers
74 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 ...
2
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0answers
453 views

Can I put a button that automatically inputs GPS coordinates into a google form? (or other spreadsheet populator)

I am currently creating a Google Form and part of the questionnaire requires the user's current GPS location. Is it possible for a button to be able to do this and automatically populate the field? Or ...
2
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128 views

About Timestamp in Geotagging

I'm on my reasearch for GPS and sensors integration. I've just wondered that to integrate between GPS and camera you need time offset synchronize which called as a timestamp. But how does software ...
2
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0answers
95 views

How do I accurately measure a gps track over a long distance?

I am measuring the length of the Continental Divide Trail that goes from the Mexican border to the Canadian border. I have a .gpx file of the entire route in NAD83 with tracks about every 50 meters. ...
2
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118 views

Create “mean” line from multiple lines using QGIS

I have multiple lines features (also have them in multipoints...) representing similar path (mountain trails, in this case) with various GPS precision, resulting in many lines close to each other, but ...
2
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52 views

Reference and Beacon Stations in Vietnam

I'm not sure if this question can be asked in this forum, but here it goes. I am on my way to conduct some remote sensing research in Vietnam, which includes logging of coordinates. This should ...
2
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0answers
104 views

How can I store height info from GPS in QGIS?

I want to use QGIS as a tool for collecting GPS-Data in the field. One use case would be simple surevy tasks where I want to store the three dimensional position of points. QGIS is working fine on the ...
2
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194 views

Is it possible to display labels in background files (.imp) on Trimble GPS units?

I have been trying to figure out if this is possible for a while now. I know if you load a file in as a data file, you can click on a feature and the label will pop up. However, you cannot view a data ...
2
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2k 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 ...
2
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175 views

best free easy GPS software? (not necessarily 'real' GIS)

Our search and rescue group is looking for some advice on what free and user-friendly (no computer savvy required) software folks could use to interact with their own GPS. Doesn't have to be a 'real' ...
2
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0answers
78 views

Calculate Moving Time

I am wondering how web apps like Garmin connect or Strava calculate a "moving time" from a gps track. For example I might record a GPS track on my Garmin GPS that has an elapsed time of 5:34:26 but ...
2
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396 views

GLONASS Satellite Position Prediction using Almanac Data

GLONASS ICD has a section named "Algorithm of calculation of satellite motion parameters using almanac". It gives the formulas in order to calculate the position and velocity of the satellite. ...
2
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241 views

how to make decent sense from scattered river depth measurements

I sampled river depth at scattered positions and I want to be able to make a map and GIS layers out of it. My problems are: As the river meanders the interpolation I do in scientific packages i,e. ...
2
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248 views

Should 2D Positions and 3D Positions be considered conceptually different entities?

Let's suppose we want to model GeographicPositions, described by coordinates or coordinate tuples inside some Coordinate Reference System. Also, these would be put inside some sequence to represent ...
2
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0answers
414 views

calculating bounding box from known centre coordinate and zoom

I have a map, the centre of that map (centrepoint) is = -37,175 ( gps) I know the zoom of the map = 13 I know the size = 320x320px I know there is 111111m in a degree of latitude and a varying degree ...
2
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133 views

How can a GPS receiver know the estimated error?

I would like to plot a circle of possible error on the map in a GPS app. From http://en.wikipedia.org/wiki/Dilution_of_precision_(GPS), we can see that GDOP is equal to "delta of output location" ...
2
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0answers
189 views

Interpolate current Course value of GPS using previous Course values

I have a set of GPS data with Lat, lon and Course. I need to interpolate current value of course, using previous values of Course. The formula I am using is not accurate in curves.In C language I was ...
2
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175 views

QGIS on android4 with bluetooth GPS

I'm trying to set up a moving map on my tablet (asus, Android 4). I've installed QGIS (latest version), which works. I've got a blue tooth external GPS, which I've paired to the tablet. However, I ...
2
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0answers
175 views

From gpx to line segment 1Km using ArcGIS 10

I have gpx files containg points with attribute data such as time and date. I'd like to convert them into lines, and that is not a problem, but what I want to do is create 1Km segments with time and ...
2
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0answers
273 views

How would I modify GPS tracker to accept two nmea inputs and gpsmarker to include a heading vector?

I use QGIS on a research vessel and wonder whether I could modify the QGIS 1.8.0 gpsinformation widget. I want to achieve two things. 1. Change the GPS marker to a boat shape which points in the ...
2
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0answers
189 views

How to enable OSM map in Garmin?

I've installed two OSM maps, but I cannot use them in Garmin. See the window of Utilities / Manage Map Products: The maps are not lockable, but I cannot use them in Garmin... What shall I do to be ...
2
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0answers
141 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 ...
2
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0answers
514 views

How to read a .GPB file in C#?

I have a .GPB file, I need to extract the common GPS data from it but I don't find a clear structure that specify the contents of that file. as a sample record from file 00000260 02 11 A9 61 E7 96 ...
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0answers
9 views

Plotting GPS plot without uploading data

I'm not sure if this is possible or not, but I'm wondering if its possible to plot a GPS dataset without uploading the data first to CartoDB. I've been analysing some data by uploading the postcode ...
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12 views

What is the lowest and highest possible pseudo-range?

I am trying to compact the required data that needs to be sent to the server to post-process the receiver's position. To do this, I figured it'd be possible to offset the pseudo-range by a fixed ...
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30 views

Average stationary position with GPS

Is it possible to average a stationary position with a GNSS (GPS, GLONASS...) with a centimeter accuracy without an external corrections (like RTK)? If so, how long does such averaging have to take? ...
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13 views

GPRS data receiving in Java

i am creating a java program that will receive data from GPS tracker device and will store it in MySQL. for this purpose i need to create a GPRS connection for receiving data. Can anyone help me how ...
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32 views

Post-processing GPS Satellite Measurements

I am working on a system that reports its location to a server using very little power. In order to achieve an extremely low power usage, I am avoiding having to download both the almanac and the ...
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15 views

Filter GPS tracks to determine “Moving Time”

I am working with GPS tracks of outdoor activities, think cycling, running, hiking. These activities often have "rest periods" where people take a break, wait at traffic lights, or just stopped their ...