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

learn more… | top users | synonyms (2)

6
votes
3answers
657 views

Using PROJ.4 library to transform from local coordinate system coordinates to global coordinate system using ground control points?

I have a point cloud whose coordinates are with respect to a local coordinate system. I also have ground control points with GPS values. Can I convert these local coordinates to a global coordinate ...
2
votes
1answer
57 views

What is “gps on demand time injection”

Android defineds a GPS device capability I couldn't find reference to It's defined as GPS_CAPABILITY_ON_DEMAND_TIME in gps.h The description in the comment explains: GPS on demand time injection. ...
0
votes
1answer
362 views

downloading waypoints from Garmin GPSmap 60cx to QGIS2.2. Am I missing a step?

QGIS2.2 64 on W7 64 is failing to download waypoints from Garmin GPSMap 60cx USB port. GPSBabel installed and the GPS Tools dialog is OK: GPS device: “Garmin serial”, Port: ”USB”, Feature type ...
0
votes
0answers
26 views

Convert WGS 84 cartesian 3D coordinates(x,y,z) to geographic coordinate (lat/long) [duplicate]

Do you know where can I find the formula and data needed to effectuate this conversion? Sorry I don't give enough information. I get the description file of a CORS ...
0
votes
0answers
30 views

How to visualize GPS dataset fro MysQL database and select dense areas

I am using Geolife dataset for simulation. I followed the pre-processing data tutorial to store all .plt files in a mysql database and export it in a .csv file. However, I want to select the ...
23
votes
4answers
32k views

What are the major differences between GPS, GLONASS and Galileo?

What are the major differences between GPS, GLONASS, COMPASS and Galileo?
0
votes
1answer
42 views

QGIS GPS not editing offline database

I have a set of layers from PostGIS that I have converted to offline. I am attempting to edit them via GPS. If the layer is point data, then I can add in that data without issue. However when I go to ...
1
vote
1answer
46 views

PostGIS and Mobile Devices Maps

I'm still learning the world of GIS reading this Introduction to PostGIS. So far I understand things but since I have an idea that I plan to later work on, I found something that I didn't quiet grasp. ...
1
vote
1answer
33 views

Transfer from Android phone to Windows OS truncates lat long

I am clicking GPS enabled pictures of sites which are less than 500 metres apart through Android based Samsung ACE Duos phone. I later use Google Earth on my Laptop to view these geo tagged pictures. ...
1
vote
4answers
275 views

exporting metadata from gps camera to spreadsheet

I have a question involving exporting metadata from a GPS camera to an application such as a spreadsheet. In essence, I'm working with a significant number of images taken with a GPS digital camera. ...
21
votes
6answers
3k views

Is GPS more accurate on specific hours of the day?

I have heard that the GPS system is more accurate, and less accurate on some specific hours on the day. If this is true, how can I get the information on when GPS is more or less accurate at my ...
2
votes
1answer
6k views

Looking for an android solution for offline kml/kmz file viewer with gps support

I have some KMZ files of cadastral maps. I need to fiscally go to the boundaries of my lands (parcels) and take a look at where they are with the gps and maps support. Some of these places are not ...
0
votes
0answers
28 views

Replicating CSRS PPP solution in RTKPOST, gLAB

I analyzed the GNSS position data using CSRS , RTKPOST, gLAB. From the results, I noticed that the CSRS results for NEU errors is the least, while RTKPOST and gLAB were comparatively larger. I tried ...
9
votes
1answer
657 views

What causes the GPS offset/shift in China?

I've spent close to two full days trying to understand the nature of the infamous GPS shift in China. After sifting through the noise, two recurring symptoms are that: GPS coordinates (WGS-84) plot ...
2
votes
2answers
103 views

GIS Equipment for 911 Call Center [closed]

I am the GIS administrator for a 911 call center. Currently we use ArcGIS for our mapping, and my director recently told me that I have a budget every year to purchase GIS/GPS equipment or training. I ...
0
votes
0answers
73 views

Is there a way to create a custom, navigable GPS route?

Is there some sort of way to create a custom GPS route that can say, be plugged into a maps app like Google or Apple maps? For instance let's say I created a route that is a drive along Pacific ...
0
votes
0answers
25 views

Processing obs files in glab (PPP)

I have data for a trimble receiver and would like to run PPP analysis for its positioning errors. I use glab for this purpose. For the orbit and clock source, I use the final orbit data provided by ...
1
vote
1answer
44 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 ...
1
vote
0answers
43 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 ...
1
vote
2answers
251 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
82 views

Getting Intra-Maps roam to interface with internal GPS

I've got Intramaps Roam installed on a Panasonic Toughpad fz-g1 with integrated u-blox M8 gps. When I open up GPSviewer I can see my position, everything seems fine. When I enable GPS with ...
0
votes
0answers
10 views

Inputs for GNSS data processing : NEU error

I have some .?o and .?n files that i need to process to obtain the NEU errors. I understand that for a very accurate estimate, i need reference stations (the more, the better) to obtain baselines. ...
0
votes
0answers
16 views

Remote USb gps device location in QGIS server

I have QGIS server in linux. I have navika usb GPS device connected to a laptop.Laptop and QGIS server are interconnected via ethernet.How do i get the GPS device location in the server as the devicis ...
4
votes
0answers
118 views

What projection system is used in China which is aligned with WGS84 [closed]

I have some GPS tracks in Beijing. I want to project it and convert the lat long degree values in meters for calculation in euclidian space. I was wondering what is the most suitable coordinate and ...
0
votes
0answers
49 views

ODK Collect GPS Accuracy

Good day. Is it possible to require a minimum accuracy of the GPS widget? I know about accuracy threshold but what I need is to prevent forward swiping/finalization of the form if GPS accuracy is low. ...
1
vote
2answers
184 views

Why does my phone's GPS suffer from “urban canyon” problems in Beijing but not New York?

In a separate question on Travel.SE I asked why my phone's GPS didn't seem to work in Beijing, China. Turns out that it was simply an "urban canyon" problem, and that the GPS did in fact work when I ...
2
votes
1answer
150 views

GPS Live tracking with qgis android

I have a Tablet 10.1 notes on which I installed QGIS Android (v. 2.8) and a Garmin GPS 62 stc. So I tried to do the "live GPS tracking" by connecting through the USB cable the GPS to Tablet. Next, ...
35
votes
9answers
35k views

Why does GPS positioning require four satellites?

I have a question on the GPS positioning algorithm. In all books I've read for 3D positioning we need four satellites, and I don't understand why. We need to calculate three variables: x, y, z. We ...
7
votes
0answers
1k views

Calculating compass bearing between two GPS coordinates… with a twist [closed]

I'm building a virtual tour application that uses Google's streetview code to render the panoramas into a non-distorted view. Each panorama has 1 to n links where the user can select to move on. I ...
0
votes
1answer
45 views

For GPS point data using android, default camera app or other software?

I'm curious to know about your experience using the default android camera app for geotagging photos vs other apps. I am going to trial a few different of these apps over the next month or so on ...
0
votes
0answers
42 views

Why does my Android always show same lat/long for geotagged photos? Can I override this?

I am looking to collect point data with my Samsung Galaxy S3 using Android 4.1.2 However, every photo returns the exact same lat/long position Is it possible to override this and if so, how?
0
votes
0answers
33 views

how do calculate nearest point in earth map with coords

I am having trouble calculating nearest point for another point with earth coordinates. I am particularly interested in calculating the intersection of linestring vector with earth coordinates. I'm ...
0
votes
0answers
29 views

Movement along a path with inaccurate location updates

Given a path and a vehicle traveling along that path. At intervals (~1 sec) the location and speed of the vehicle along that path is provided. The location of the vehicle is not accurate, a noise ...
0
votes
1answer
47 views

Map Positioning and Routing on Android

I have been instructed to create an small offline application in Android that have to: a) Use our own map in JPEG format as the basemap (Google Map / OpenStreet Map is not applicable) b) Show the ...
2
votes
1answer
65 views

Getting started with RTK base stations

My employers are looking into a partnership with a company that provides RTK base stations (they specialize in Topcon equipment) and are planning to replace our old total station with a Topcon HiPer ...
0
votes
2answers
78 views

iPad with real GPS

Historically, iPads have not had true GPS. The GPS they have goes through a cell phone network, called Assisted GPS. Now I hear that iPads are coming with true GPS. How do I know if a particular iPad ...
1
vote
2answers
318 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. ...
2
votes
1answer
227 views

Converting GPS cords to X Y based on wrapper

I'm trying to create some software for an airport and they require me to place icons of aircraft in their position based on GPS. I have 10x10 tiles each tile being 256x256 pixels and the origin point ...
1
vote
2answers
277 views

How to import GPS waypoint, track info into ArcMap 10.2?

I heard that ArcMap 10.2 can import waypoint and track information directly from a GPS without bridging it from MapSource or BaseCamp software. Can someone give me tutorial or link to a video that I ...
0
votes
0answers
29 views

Regarding processing of GNSS data heights

I have a TRIMBLE GPS receiver and in its data, I am able to derive the ECEF xyz coordinates. My objective is to obtain the orthometric heights, which I could do using the equation h = H + N. My ...
2
votes
2answers
64 views

How do some companies receive GPS data from vehicles if GPS's can't send any data?

I know that some companies offer tracking services for vehicles such as live GPS tracking they can access any time, but as you can't use the GPS protocol to send any data i wonder how the do it... I ...
0
votes
0answers
32 views

road network construction using latitude longitude and timestamp

I have gps data(latitude,longitude and timestamp) of a city over a month I want to use some routing algorithms on that data so need to construct road network or graph So how to construct road network ...
2
votes
1answer
155 views

How to change ODK GPS accuracy threshold?

I am using ODK with ONA in XLSForm. As the GPS accuracy default is 5 meters, it automatically accepts it when it reaches 5 meter. Is it possible to change the default accuracy to less than 5 meters ...
0
votes
0answers
191 views

Can't find GPS in QGIS for Android

I have installed QGIS on my samsung galaxy note 10.1 (not 2014 edition) but I can't get contact with the GPS. I have the GPS information tool, but when I try to connect, QGIS shut down or nothing ...
0
votes
0answers
21 views

M-field to a point layer calibration (Linear Reference)

I am working with routes with ArcGis 10.1 and I'm trying to calibrate the routes using a points layer imported from text file obtained from a GPS. But the points layer doesn't have m-field to be ...
0
votes
0answers
41 views

Generating Random Location (newLat,NewLon) given current position lat,lon)

I have been trying to implement a method described on this site to generate a random location given my current position. It is described here: How to generate random locations nearby my location?. ...
2
votes
0answers
47 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
votes
1answer
166 views

Does GPS correct for continental drift?

Does GPS correct for continental drift, and if so, how? (I'm mainly interested from the perspective of consumer devices such as smartphones.)
0
votes
0answers
108 views

Getting OpenLayers degrees rotation to point right way?

I am working on a fairly simply proof of concept for a tutorial to blog. At the moment it is simply to show how a SatNAV type functionality could be achieved in a browser - However I cannot for the ...
0
votes
0answers
75 views

GLONASS speed and altitude limitations

I'm looking for some info about the possible limitations for the GLONASS navigation system, something similar to the GPS COCOM limits. Is there any limitation on speed AND/OR altitude for this ...