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

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How do I calculate ECEF X,Y,Z velocities for GPS if I have no satellites

I'm attempting to simulate a GPS message where know variables are starting location, ending location, speed (m/s), and a bearing (0 - 359 degrees). How can I calculate the ECEF X, Y, Z velocities ...
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52 views

Calculate XYZ velocities between 2 ECEF points [duplicate]

Possible Duplicate: How do I calculate ECEF X,Y,Z velocities for GPS if I have no satellites If I have a starting location (Latitude/Longitude), a bearing (degrees), and a speed (m/s), how ...
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3answers
5k views

Distance between GPS coordinates

Given a database of GPS points, a center GPS location, and a radius R (in meters), how can I find all points in the database that are within a distance of R of the center point? Will the distance ...
7
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1answer
211 views

Analysis of GPS error

I'm wondering if there have been any studies which attempt to analyze or characterize GPS error distribution over different situations/conditions (e.g. surrounded by tall buildings/mountains, ...
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1answer
487 views

Sensitivity of Garmin eTrex 30

I have a very good experience with Garmin eTrex Legend HCx - here and here they write that HCx has a very sensitive chip, that works in forest, deep valleys and in cities - and I can only confirm - ...
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1answer
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Difference between Garmin eTrex Legend HCx and eTrex 30?

I have used etrex Legend HCx a lot and been satisfied. Now I've seen etrex 30 just for a while and it seems to me that the Legend is much more user friendly, good old menus with a lot of ...
3
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2answers
413 views

Classification of GPS trajectory

I need a detailed description of a GPS trajectories. I don't need to know what a GPS trajectory is, I already know it. Exactly I need a paper (better if scientific cut) that talk about different type ...
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3answers
891 views

GPS Elephant Tracking: Utilizing A-GPS, WAAS, DGPS and Understanding HDOP, NSAT, and ZDA

*I'm using a GPS data logger (qstarz bt-q1000xt) to track the movement of zoo elephants, and I have a variety of technical questions. I've had limited success receiving answers from the vendor. You ...
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2answers
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Using OpenLayers (with OpenStreetMaps) and PostGis for rendering data acquired from GPS tracking device?

I'm researching and planing to acquire data from GPS device and store them in postGIS database, then use geodjango to process/work them out and finally chart them on a map with OpenLayers. Will these ...
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0answers
127 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 ...
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1answer
552 views

Overview of GPS tracking system technologies

Background: I've been asked by a friend to estimate the cost of setting up a GPS tracking system for a small fleet of buses, so we can do real time reporting of bus locations via a webmap. In my ...
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4answers
3k views

Connecting GPS to ArcGIS via USB

Is there a way to connect a GPS to ArcGIS via USB? At the moment the GPS extension only appears to support comm port connections. It would be good to know if a USB connection can be made, then perhaps ...
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1answer
321 views

Differentially correct GPX file

Is there any way to differentially correct a GPX file using free or open-source tools? Does a GPX file contain the necessary information for differential correction (I can put the timestamp in it ...
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1answer
2k views

Go to X,Y dialog box

If someone gave you a x,y coordinate numbers he/she got from. I put the numbers in the X,Y events on my ArcMap and they are in Meters numbers. We entered the number into the x,y dialog box. The ...
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2answers
2k views

GPS Module Without Velocity or Altitude Limitations

I am looking for a GPS module that I can use in a high-altitude project. The problem I have discovered is that GPS manufacturers are required to place a set of restrictions on GPS modules. The ...
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2answers
2k views

What algorithm should I use to remove outliers in trace data?

I have GPX traces and want to remove outlying observations. There are some route points that are impossible because it would require acceleration that the vehicle can not achieve. Are there good ...
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1answer
327 views

What GPS unit can I use to track myself all day for a 10 day trip? [duplicate]

Possible Duplicate: Logging GPS and Accelerometer Data - Device Suggestion? I will be visiting China this October as part of a field studies course and I want to be able to take the ...
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2answers
264 views

Is there a time limit on post-processing GPS data with Pathfinder Office?

Do I need to post process my GPS data within a certain amount of time after collection? Do the services that provide the correction data to Pathfinder Office only make that data available for a ...
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3answers
2k views

GPS post processing - Differential Correction

I have a large set of collected GPS points that I'm pulling into Arcgis from SQL and creating an xy event layer to then map them. The fields for the points are as follows: recorded, lat, long, ...
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3answers
954 views

GPS drift during the receiver is stationed

I have developed a GPS Tracking device it is working fine when the receiver is in motion, when it stationed in a position for couple of hours i get some drift for around 10-15meters. The receiver send ...
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1answer
2k views

how to calculate RMS 2D and RMS 1D, using python?

I would like to calculate: RMS 2D: standard deviation for the two coordinates of flat (67% confidence level) and RMS 1D: standard deviation for height (67% confidence level) What is the formula and ...
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1answer
7k views

How to batch convert Garmin GDB to GPX?

I need to convert a lot of garmin GDB files to GPX in order to convert it to another vector format. Is there any tools available can do a batch convert from garmin GDB files to GPX? Using MapSource ...
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1answer
112 views

Programs to log NMEA on Nomad 900?

I am interested in logging NMEA data on a Trimble Nomad 900. Unfortunately the SatViewer records a maximum of 64,000 characters, too little for my application. I don't want to have to purchase ...
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305 views

Is there open source GPS post-processing software? [duplicate]

Possible Duplicate: Post Processing GPS Data with open source software Here at the office we have a couple of 15-year-old Trimble 4700 and 4800 units but now we don't have the software to ...
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4answers
9k views

Why is GPS a free service?

The Global Positioning System (GPS) is a free service that is owned and operated by the U.S. Government and is always available. When we buy a GPS device, we don't pay a monthly fee or pay a tax for ...
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2answers
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What is the difference between triangulation and trilateration?

Looking around I noticed that many people exchange the terms (tringlulation and trilateration) for the same sense. What's, actually, the correct sense of Triangulation and what are the differences ...
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5answers
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How to get an elevation profile for a gps track?

I'd like to get a reasonably accurate elevation profile for a track recorded with a GPS (which often has very unreliable altitude data and occasionally none at all, depending on the model.) Does ...
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3answers
100 views

Looking for a website to produce a file using UTM or LL or LL to UTM or general

Is there a website that allow me to upload my GPS file from UTM to lat and long to produce a new output file ? I am looking for one to run a batch a list of UTM or LL to converstion them in either ...
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1answer
1k views

How to calculate accuracy of latitude/longitude

I'm updating a Windows Mobile application to capture location information using the built-in GPS hardware. The Microsoft API provides a method GPSGetPosition that returns the following struct ...
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1answer
1k views

How to filter wrong GPS readings?

I have absolutely no experience with GIS, it just so happens that one of the hobby projects I am doing at the local hackerspace includes tracking a model boat with a GPS... I hope this is the right ...
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11answers
2k views

Device for Logging GPS and Accelerometer Data?

I am looking for a device that can track my location (lat,long) and speed all day long. Perhaps, I need GPS and accelerometer data bundled together. What I want to do is to log my daily activities. I ...
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1answer
4k views

How to calculate Bearing between two GPS points

The following returns 150 degrees using C# converted from JavaScript Bearing formulas, but Google earth returns 210 degrees for the same values. The broken code is GetBearing() but I've also included ...
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3answers
435 views

GPS and GIS for real time monitoring of an object

How is it possible to store coordinate of object in server in real time using feasible hardware ( can be used by student) GPS into database and retrived in real time?? What are the names of ...
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2answers
309 views

GPS capable rangefinders or cameras that can capture lat / long data from a distance?

Anyone have experience using this technology? i.e. field verifications of structures where you need to capture the lat / long of a house that is 1000 feet from the road with limited access.
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2answers
786 views

Alternative to Terrasync for Trimble Windows Mobile unit

I have a number of Trimble Nomad 900 series devices and am currently using TerraSync. TerraSync does the job, but are there any other alternatives out there that would be even simpler to use? ...
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0answers
290 views

Draw a skyplot with calculated ECEF values (in meters)

I have ECEF values that I calculated from ephemeris subframes 2/3. Using this information, I'd like to place these values on a skyplot based on my current location. I'm using a C# picture box for my ...
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3answers
3k views

Example of a Dynamic Map Service that frequently changes?

A requirement of our web application is to automatically refresh a particular dynamic map service on a timer. Requirement relates to a client who has a dynamic MS that consistently gets updates ...
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4answers
706 views

Looking for software to interface GPS data with PC

I have GPS Unit from Garmin (GPS 18xPC). I'm looking for software I can install on my PC that will allow me to interface with the data I collect on my GPS unit. Any help will be great
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1answer
329 views

How to export offsets from Trimble Rangefinder?

I already asked this question at http://www.rpls.com/forums/viewtopic/8/1276880, but didn't get any answer so far. Maybe here someone can help... I have a question about the use of Trimble Products. ...
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6answers
2k views

Sources of realtime spatial data

I'm trying to set up a demo that serves up live spatial data, but am having trouble finding any suitable example data sources. Ideally I'm looking for something that updates every few seconds; either ...
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8answers
23k 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 ...
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2answers
521 views

What Type of GIS Powers Automobile Navigation Systems

My sister-in-law was inquiring about where she can buy updated DVD's to load into her car's system. Obviously I know the dealer/OEM would love to rip her off for such data, and I knew of no ...
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12answers
3k views

Location-based game using GPS

I am not sure if this forum is proper place for that kind of question but i hope to get some advice... I looking for some scenario (examples, ideas) for urban game (location-based game) with usage of ...
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1answer
324 views

What is the DNSC08 Mean sea surface model ellipsoid based on?

Does anyone know what Danish Space centre DNSC08 mean sea surface model uses as the reference ellipsoid? there is no meta data on the web site: ...
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1answer
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how to convert the easting and northing to a point and saved in a feature class in ArcMap?

I write a program to decode the message from the GPS device to get the easting and northing , but I don't know how to convert the easting and northing to a point and saved in a feature class in ...
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2answers
861 views

GPS - Garmin 60CSX connectivity issue

I have a Garmin 60csx, about 2 years old and I have attempted to connect it to my laptop/ArcView (GPS toolbar) using the Detect GPS Port to no avail. There is no port number being displayed and that ...
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0answers
421 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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1answer
132 views

Finding intermediate points and speed over a segment

I have a dataset which is in the form of ( Time , Car ID, Speed at that moment, Lat,Long) and I need to do some machine learning on the data to answer the following questions : Best route from ...
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How do I download tracks from the GARMIN GPSMAP 78 usin DNRGarmin?

I have been able to download waypoints to DNRGarmin by accessing the GPX file. However, I have only been able to view waypoints. How can I download tracks?
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1answer
1k views

How to read multiple .gpx files in R [closed]

Suppose I have a number of .gpx files (these contain GPX waypoint data from a Garmin eTrex). I want to load them into R with different names and manipulate them. I can read one file thus: ...