Questions tagged [gps]
Questions regarding the Global Positioning System's satellites and uses.
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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 ...
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Is the full GPS constellation a Walker Delta constellation?
Through the extremely rigorous method of looking at the animation on Wikipedia's article about GPS, if this does indeed accurately represent GPS satellite orbits, then it looks like not all of the ...
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Receiver location calculation based on Rinex navigation and observation files [duplicate]
I am trying to calculate the location of the GNSS receiver using the data available in the Rinex navigation and observation files. As a first step I am trying to calculate the pseudo range using the ...
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Add small extra gps antenna on tracker installed inside aluminum tube [closed]
I would like to install a GPS tracker inside a scooter. Will the GPS signal will be lost if I install the tracker inside the vehicle?
Can I add a small extra antenna to fix outside the scooter?
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What is the slantRange of a GPS
How can I know the slantRange of a GPS in the aer2ecef function
thanks
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How can I calculate GPS satellite's Latitude and Longitude if I have the elevation, the azimuth, the XYZ coordinates of the ground station
How can I calculate a GPS satellite's latitude and longitude if the elevation, the azimuth, and the XYZ coordinates of the ground GPS station are provided?
I have tried these questions:
Computing GEO ...
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How can I calculate GPS satellite's Latitude and Longitude if I have the elevation and the azimuth
Please tell me how I can calculate a GPS satellite's latitude and longitude if I have the elevation and the azimuth angles.
I am using a septentrio GPS receiver.
Thanks
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How to download (Assisted GPS) AGPS file on PC?
I am trying to implement GPS receiver in software. Can I use AGPS file for faster locking of GPS satellites? I read somewhere that EPO files exist for Assisted GPS but I can't find any place to ...
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If the pseudorange is not fixed, how does a receiver lock/fix onto a satellite signal?
If the satellite moves around the orbit at a velocity, the pseudorange between the receiver and the satellite should be changing right? If so, how does a receiver lock onto a satellite signal if the ...
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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 ...
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GPS SV velocity mismatch
When using classic Newton's second law we have
$$
\vec{F} = m \vec{a}
$$
$$
\vec{F} = G \frac{M m}{r^2}{e_{r}}
$$
$$
\vec{a} = \left( \frac{d^2 r}{dr^2} - r \left( \frac{d \phi}{dt} \right)^2 ...
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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 ...
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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 ...
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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 ...
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Why using internet connection speeds up the GPS positioning? [duplicate]
I noticed that when I activate my cell phone internet connection, I get my GPS position much faster.
What does the internet connection provide for the GPS receiver ?
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What is "Time To First Fix" in GNSS?
I used an app to test GPS, that shows me TTFF is equal to a few seconds.
I want to understand :
What is Time To First Fix?
Is having internet access useful to improve it?
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Is Satellite Based Augmentation System ,used in GPS, a Differential Technique?
I've read that to get a higher accuracies in GPS, we use differential positioning techniques which compute for satellites errors, using well-known position base station.
I want to know if the ...
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Does using multifrequencies totally eliminate the ionosphere delay on GPS measurements?
I've read that the GPS receiver computes the difference in measurement for two GPS satellite signals (in two frequencies L1 and L2), in order to compute the actual delay that the ionosphere causes.
...
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Why does GPS need the fourth satellite?
I am currently working on a GPS project, so I am doing some research about the subject. I understand that the GPS receiver knows its location by calculating its distances from 3 satellites, and by ...
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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 ...
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How can cosmic ray muons be used to replace GPS for positioning information in 3D on Earth and underwater?
Task & Purpose's The Navy is testing a GPS-like device that doesn’t require satellites
“The future is extremely bright for this line of research." begins:
The Navy is researching a new ...
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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 ...
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Can the James Webb Space Telescope's position be determined using GNSS? And if not, how is this done?
As far as I know, the recently launched James Webb Space Telescope will be positioned at 1,500,000 km of the Earth, orbiting Sun-Earth L2 Lagrange point at roughly 4x the distance between the Earth ...
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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) ...
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Why end-of-life GPS satellites given orbits that seemingly still intersect active satellite orbits but with a different period? Recipe for disaster?
This answer to Where are MEO satellites put at the end of their operational life? says (currently in full):
This is an active area of research. As you noted, the main satellites that are in MEO are ...
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How is the ambiguity in code phase resolved in GNSS code-based positioning?
For positioning using GNSS, a typical introduction text (example PDF) introduces the concept of pseudo ranges as roughly being the time between transmission of a GNSS signal by the satellite $s$ and ...
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Ephemeris time and clock corrections in RINEX navigation files
RINEX (Receiver INdependent EXchange format) is a set of file formats to distribute satellite navigation systems data, including GNSS. One of these standards, navigation files, provide positional ...
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generated error terms for positioning based on a pre defined target accuracy level
I would like to ask a question about accuracy level and precise point positioning or PPP.
I'd like to design a system such that when the desired accuracy level is provided as an input, the ...
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Lunar satellite navigation system
Inspired by some questions:
Are People Actually Serious About Mining The Moon?
How to estimate that receiving GNSS signals Earth while orbiting the Moon will still provide locations to about 200 ...
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Could a satellite use a Miniature Atomic Clock (MAC) to provide GPS services?
I've been investigating GPS satellites and I got curious about onboard atomic clocks. I found this following paper on the concept of a CubeSat GPS constellation using Chip-Scale Atomic Clocks, and ...
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Could a single CubeSat provide location services on another celestial body such as Mars? Could a constellation do it?
From my understanding, by having two satellites emit a signal simultaneously (carrying atomic clocks to achieve it), a ground device could measure the difference in times of arrival to determine its ...
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How to convert GPS time to TAI time to UTC time?
I had naively assumed that GPS time and TAI were the same thing until I saw this answer:
https://space.stackexchange.com/a/22244/12508
I know that there are differences between Terrestrial Time (TT) ...
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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 ...
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Precise timing using GPS
Looking at https://gssc.esa.int/navipedia/index.php/GPS_Navigation_Message and other websites, in order for a satellite receiver (which doesn't have other means of getting precise GPS time) to ...
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Geolocalizing photographs on astronomical bodies
In Are pictures taken from ISS geolocalized? I was considering photos taken on the Moon by astronauts. How can I determine a photographer's position and lens direction?
And further, since there isn't ...
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Alternative to GPS navigation for vertical landing, especially on other planets
Is the GPS data reliable or meaningful only on Earth or below the geo-stationary Earth orbit? For GPS navigation, does a rocket has to fly below the geo-stationary orbit? If GEO is a physical ...
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Does Falcon 9's first stage use laser, radar or vision to assist landing? [duplicate]
Does Falcon 9's first stage use only GPS when it makes its vertical precision landing, or is it assisted also by radar or laser ranging or computer vision? If not, why not?
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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 ...
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How to estimate that receiving GNSS signals Earth while orbiting the Moon will still provide locations to about 200 meters of uncertainty?
IEEE Spectrum's Can Astronauts Use GPS to Navigate on the Moon? NASA Scientists Say Yes says:
Kar-Ming Cheung and Charles Lee of NASA’s Jet Propulsion Laboratory in California did the math, and ...
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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 ...
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Two line element set
I was wondering where I could find the TLE of a satellite ( I am looking for CASSIOPE). I went into this link - https://www.n2yo.com/satellite/?s=39265 but it has only got the most recent updated TLE. ...
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What will the US government start to label its GPS spacecraft after SVN 99
GPS spacecraft are currently identified by their “Space Vehicle Number” (SVN) which now number 01 through 75. What will happen after 99 GPS satellites are launched? Is there any plan currently in ...
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Could a Falcon Heavy really put six GPS Block III satellites in orbit at the same time?
This answer says:
GPS Block III satellites are being launched to replace failed or aging Block II satellites, which doesn't require launching more than one at a time. A Falcon Heavy could fill up ...
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Why multiple GPS satellites are never launched on the same rocket?
From what I've read, GPS satellites have been always put in orbit one at a time. In contrast, Galileo (aboard Ariane or Soyuz) and GLONASS (aboard Proton) sometimes are launched at the same time. Is ...
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When going to Mars, how do you measure exact distances to determine course corrections?
When probes fly to Mars, they must adjust their trajectories multiple times during transit to ensure correct orbit insertion. They fire their small onboard rockets a little bit to do this.
But how do ...
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Delay-Doppler maps in space science
Maybe this question might be more physics related, but I've read about mostly in context of space science:
What is a delay-doppler map (DDM)?
I can find it
in exploration of asteroids (e.g. (...
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What is GPS' 19 year rollover and does it present a cybersecurity issue?
The NPR new item and audio podcast The Global Positioning System Resets talks about a 19 year cycling of something in the GPS system, but it's not clear what it is.
Every 19 years, the Global ...
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Does GPS spoofing ever come from space? How are spoofings usually detected?
The BBC News article Study maps 'extensive Russian GPS spoofing' says:
(GPS spoofing) involves the state using strong radio signals to drown out reliable navigation data, says non-profit C4ADS.
The ...
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What is required to make GPS signals available indoors?
GPS satellites don't transmit strong enough to reach indoors, through the roofs and walls of buildings, like cell phones do. GPS signals that enter buildings through windows are unreliable since they ...
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GPS PPS stable signal [closed]
My question concerns the GPS NMEA reading data about PPS signal.
Is there any way to know via software using NMEA that the GPS PPS signal provided by its outport is already synchronized with the one ...
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