You are here: Foswiki>Forum Web>WebHome (26 May 2014, RickMach)EditAttach

Welcome to the GPSTk Forum web

To create a new discussion entry, create a 'New Discussion Forum'. This will create a slashdot.org style main article with the ability to add comments to the posting. If you want a new category of items, you have to add an the category to the 'Form Categories'. Let RickMach know if you have questions or feedback.

New Discussion Forum Forum Categories

Predicting Sattelite Positions - Wheresat
Posted on 28 Sep, 2016 by KasperGl

| Dear m8's

We are trying to create an NMEA Stream simulator that contains the "correct" predicted sattelite positions:

We are trying to use the wheresat tool for this purpose:

When using GPS Yuma almanacs from https://celestrak.com/GPS/almanac/Yuma/2016/

W e can user wheresat for example:

wheresat -e yumafile.alm --pos="x y z" --start=""09/25/2016 00:00:00" --end="09/25/2016 23:59:00" --time="900" --prn="5"

this returns a listn and we can see when PRN 5 is in view and at what elevation it should be. -->Problem: It does not match reality at all! In real we see sats that should be invisible and oposit. (provided x y z Location is correct)

When using Rinex files from here: http://cddis.nasa.gov/Data_and_Derived_Products/GNSS/broadcast_ephemeris_data.html

wheresat -e brdc2710.16n --pos="x y z" --start=""09/25/2016 00:00:00" --end="09/25/2016 23:59:00" --time="900" --prn="5"

Wheresat crashes. Is the file corrupt or is there a problem with wheresat / ephreader?


So i am not sure to fllowing questios:

- what exact files do i have to use to predict Sattelite Positions for near future

- should it work with the Rinex Broadcast files?

- am I doing something wrong?

Id be happy for an advice! Regards and Thanks |

( comments ) last update by AdminRickMach 12 Apr 2017 - 19:22

Precision of orbit prediction with SatOrbitPropaga
Posted on 12 Jan, 2017 by EvgenyB

| Hello everyone!

Could you help me please. I use the GPStk for the prediction of satellite orbit. I use class SatOrbitPropagator. I have exact ephemeris for the Radarsat-1 satellite. I try to propagate ephemeris and i have big difference with exact coordinates. I see that coordinate mistakes increase very fast. For example: on 8 minutes i have difference 900 meters by X coordinate on 16 minutes i have difference 2100 meters by X coordinate ... on 112 minute i have difference 22200 meters by X coordinate.

I use standard integrator RKF78. I try to use different variation of orbit models(atmosphere, gravity, Solar radiation pressure, etc), but i have a same resulats(difference with using different models constitute some meters).

What precision of SatOrbitPropagator? Can i use SatOrbitPropagator for 112 minutes? | ( comments ) last update by EvgenyB 12 Jan 2017 - 11:48

GPSTk in Python
Posted on 27 Nov, 2016 by CrypTo

Hi to all,

few years ago was GPSTk project in C++ implemented. Now i see that Python parts are added to GPSTk.

I would like to understand what is the aim.

Should GPSTk be 100% in Python and in C++? Or should Python be the main branch? What brought to the decision to transfer the C++ code to Python?

Regards

| ( comments ) last update by CrypTo 27 Nov 2016 - 15:45

Not all apps found in the newest toolkit release
Posted on 01 Nov, 2014 by OndrejDaniel
Hello everyone, I could not find several GPSTk applications in the newest version of the toolkit, however, I could find them in an older version. To be more specific, for example the application 'wheresat' is not located in 'bin' directory in gpstk-2.5.linux.x86_64.tar.gz archive, however, I can find this application in gpstk-2.3.linux.x86_64.tar.gz archive. The same holds for other applications.

Could you please clarify what is the reason for that?

(The archives have been downloaded from http://sourceforge.net/projects/gpstk/files/).

Thank you very much! Best regards Ondrej
( comments ) last update by AnthonyWillis 10 Nov 2016 - 19:27

ResCor not acknowledging -OF gpstk Ver. 1.2
Posted on 03 May, 2016 by BrettVel

| Hello there, I am currently encountering an error when running my rinex files through ResCor of gpstk Ver.1.2 in that when I attempt to use the command

ResCor "-IFdfdata02250.15o -OFionodata02250.15o --nav log02250.15n --Rxhere -AOSP -AOSR -AOEL -AOAZ -AOLOA -AOLO"

I receive

ResCor, part of the GPS Toolkit, Ver. 4.1 9/21/09 (ed. 3.5 6/21/2007), Run 2016/05/03 16:30:56 Errors found in command line input: Output file name required: use -OF<name> ...end of Errors

So I don't know what the particular issue is as I do have -OFionodata.15o in the command and I receive the same error report as if I didn't include that part at all so I was wondering if anyone here would be able to tell me what I can do to have this work properly. Any help is appreciated. |

( comments ) last update by BrettVel 03 May 2016 - 22:50

Archive
- Precision of orbit prediction with SatOrbitPropaga
- GPSTk in Python
- Predicting Sattelite Positions - Wheresat
- ResCor not acknowledging -OF gpstk Ver. 1.2
- Problem using PRSolve with RINEX
- installing and building gpstk on ubuntu
- Ephemeries files at current day
- python bindings problems in 2.5
- Not all apps found in the newest toolkit release
- Problem with ModelObs
older articles

Forum Web Utilities

Topic revision: r13 - 26 May 2014, RickMach
 

This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Foswiki? Send feedback