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Questions tagged [gps]

Questions regarding the Global Positioning System's satellites and uses.

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7 votes
0 answers
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Are software defined GNSS (GPS) receivers legal under ITAR and other export regulations?

With the latest update to ITAR rules, it looks like covered GNSS receivers are defined as follows: (2) Global Navigation Satellite System (GNSS) receiving equipment, as follows: (i) GNSS receiving ...
Manuel Menzella's user avatar
7 votes
0 answers
376 views

Interpolating precise ephemerides of GPS satellites

My objective is to obtain at least a sub-meter position accuracy by interpolation of the GPS ephemerides. There is conflicting research outside, where some authors state that a simple Lagrange or ...
Samuel Low's user avatar
6 votes
1 answer
71 views

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 ...
allexj's user avatar
  • 59
5 votes
0 answers
235 views

GPS Receiver Autonomous Integrity Monitoring (RAIM) - parity space method

I am trying to understand RAIM. My teacher explained three RAIM methods, I will just quote all of them because I think that the jargon might not be consistent. Maximum separation / Position ...
MrYouMath's user avatar
  • 151
4 votes
0 answers
94 views

What’s a good chip for raw GPS data for astrodynamics purposes?

I have a Raspberry Pi and a Beitian 180 GPS receiver, but it only outputs NMEA messages with observables like the satellites azimuth/elevation, local UTC time, etc. I’m planning on converting the GPS ...
gaharaz's user avatar
  • 121
4 votes
0 answers
145 views

How do you compute horizontal coordinates of a GPS satellite from its broadcast ephemeris?

I'm not an astronomer by any means, and am trying to extract the horizontal coordinates, azimuth and altitude, of a GPS satellite given its most recent broadcast ephemeris. Here is some example ...
Matthew Trotter's user avatar
3 votes
0 answers
210 views

Why does this "satellite antenna at the Laguna Peak Tracking and Injection Facility" look so weird? (two dishes back-to-back)

The video 1967 Navy Satellite Navigation training film (IBM 7094 data center) after 11:57 (older version here) the narrator says: For every pound of satellite in ...
uhoh's user avatar
  • 149k
3 votes
0 answers
152 views

Are LHCP L-Band antennas for Cubesats available?

I am designing a cubesat to carry out GNSS reflectometry or GNSS-R. To collect the earth reflected signals, I need a nadir pointing array of patch antennas, with Left Hand Circular Polarisation (LHCP) ...
Luke O's user avatar
  • 31
2 votes
0 answers
26 views

Extract GPS navigation messages from a RINEX navigation file

As a hobby project, I want to implement methods from the "GPS Software Attack" paper, which involves modifying GPS navigation messages. With this goal in mind, I am looking for: Examples of ...
David Khosid's user avatar
2 votes
0 answers
339 views

Time parameters in RINEX navigation file

Currently, I am trying to determine the position of a GPS satellite from a RINEX navigation file. I am using RINEX 2.11. Tables A3 and A4 describe how navigation files are structured. In order to ...
alex05's user avatar
  • 21
2 votes
0 answers
67 views

What is the difference between SBAS and PPP used in GNSS accuracy corrections?

I've found that Satellite Based Augmentation System uses reference stations to compute a model for correction and send them via a master station to a geosynchronous satellite, then to GPS receiver. I ...
Yahya Aouled Amer's user avatar
2 votes
0 answers
80 views

Understanding the paper "Determination of Satellite Orbital Elements by Means of On-Board GPS Receiver and Its Verification" by Yoshiwo Okamoto et. al

I have been assigned with implementing the algorithm proposed in the paper "Determination of Satellite Orbital Elements by Means of On-Board GPS Receiver and Its Verification" by Yoshiwo ...
Karl Johan's user avatar
1 vote
0 answers
178 views

How is the GPS signal transmission time encoded in the GPS signal?

I am trying to really understand how GPS works, to be able to "explain it to my grandma" level of understanding. One key aspect that I can't find an answer to is: how is the GPS signal ...
largehadroncollider's user avatar
1 vote
0 answers
48 views

How does "onboard GPS" suggest "escalation speed and severity of a storm caused atmospheric drag to increase up to 50 percent"?

Engadget's says: A recent batch of SpaceX’s Starlink internet-beaming cubesats met with tragedy on February 3rd when a 49-member cohort of the newly-launched satellites encountered a strong ...
uhoh's user avatar
  • 149k
1 vote
0 answers
77 views

Examples of both hardware and software GNSS recievers

I am writing an essay titled: Critically evaluate the positional fixing capabilities of current smartphone technologies for real world GIS data collection I am wanting examples of both hardware and ...
Tom Haywood's user avatar
0 votes
0 answers
114 views

How to read .eph (GPS Ephemeris binary data) sent by the receiver

My GPS receiver can share ephemeris info as binary data. The queried data is having .eph format. I tried to open it in Notepad but seems unreadable (gibberish). Is there any specific software to open ...
shah's user avatar
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