Gps Definition and 128 Threads

Hi all I need to add GPS digital output (in form of Lat/Long) in an existing analog audio signal whose bandwidth is 100 Hz-20 KHz. This GPS data should be added in such a way that it should not interfere with audio signal neither total bandwidth of analog signal should exceed 40 KHz. This...

Hi, we had a thread some time ago about GPS satellite system. One starts considering the ECI coordinate system in which the Earth's center is at rest with axes pointing towards fixed stars. One may assume it is an inertial frame in which the Earth's surface undergoes circular motion. Clocks on...

Who decides finances in a state school or public medical practice? They are funded from the government right, and then for small amounts I guess they are able to do what they want. But for a certain amount I assume they would have to get the government's permission?

Consider the following example: Point A has coordinates 45 lat, 0 long. Point B has coordinates 45 lat, 2 long. Both points are 5000 ft above sea level. The distance between them is X. Point C has coordinates 45 lat, 100 long. Point D has coordinates 45 lat, 102 long. Both points are at sea...

Hi all I want to develop a miniature system using GPS receiver, a micro-controller, an RF transmitter and its receiver. The idea is to acquire lat/long of buoy dropped in sea which is equipped with miniature GPS receiver (with associated circuitry) which can send its position (lat/long data) to...

Hi, starting from this old thread GPS clock synchronization I've a doubt about the physical process employed to synchronize clocks bolted on GPS system satellites. We said that clock synchronization is frame dependent. In other words we must select a coordinate chart (aka reference frame) that...

Briefly, the problem; stolen bicycles are notoriously difficult to recover. Designing a GPS tracker to fit on one is challenging, because bicycles rarely have their own available power source. Whatever GPS unit is used must typically have its own battery as its sole source of power, which...

This seems like a trivial question at first, but I am struggling how to get it right. If I have 2 GPS (lat, lon, height) observations P1 and P2 taken at some height from the Earth's surface, how do I calculate the straight line distance between them? I am using the picture below to illustrate...

https://arstechnica.com/science/2019/12/gps-is-going-places/ I really liked this article. It is not too long. Read it. The 5 ideas are: Feel an earthquake (@davenn will like this) Monitor a volcano Probe the snow Sense a sinking Analyze the atmosphere

I'm a bit lost at how to exactly start this exercise... As far as I understand we need to first determine ##d\tau_E## and ##d\tau_S##. First question: Since we can neglect the Earth's movement, can I also neglect the movement of the satellite with respect to the far away observer? If so, I...

Homework Statement The GPS (Global Positioning System) satellites are approximately 5.18 m across and transmit two low-power signals, one of which is at 1575.42 MHz (in the UHF band). In a series of laboratory tests on the satellite, you put two 1575.42 MHz UHF transmitters at opposite ends of...

Homework Statement Prove that ##D_\infty/\langle R^n \rangle\cong D_{2n}##, where ##D_\infty=\langle R,S \mid S^2=e, SRS=R^{-1}\rangle##. Homework EquationsThe Attempt at a Solution Pick ##g:\{R,S\} \to D_{2n}## such that ##g(R) = r## and ##g(S) = s##. We note that ##g(S)^2 = 1## and...

There are many popscience articles about relativity and how relativity is essential for GPS and in many is mentioned something like this: If GPS wasnt corrected for time dilation predicted by GRT, there would be an error of 12 kilometers in GPS positioning per day. But when I checked how GPS...

Why do GPS need a cesium clock accurate to 10ns? Is this strictly for time keeping or is there some synchronization between satellites?

Greg Bernhardt submitted a new PF Insights post The Schwarzschild Metric: Part 3, A Newtonian Comparison Continue reading the Original PF Insights Post.

Greg Bernhardt submitted a new PF Insights post The Schwarzschild Metric: Part 2, The Photon Sphere Continue reading the Original PF Insights Post.

Greg Bernhardt submitted a new PF Insights post The Schwarzschild Metric: Part 1, GPS Satellites Continue reading the Original PF Insights Post.

Hi,In GPS there is a P-code which stands for Precision code. Recently I heard of a so called M-code. Is it the same as P-code or something else?Senmeis

Ok, so pardon my ignorance if this can found easily online but I have these few questions. I was actually reading quite a complicated article about GPS and relativity but it had too much maths in it for my abilty. Ok, first of all, apart from the complicated details regarding the workings of...

Hi,what does it mean by „cryptographic GPS signal“? P code of military GPS signal?Senmeis

Hi,I’m looking for online video lectures about principles of GPS but couldn’t find them. Can anybody recommend some?Senmeis

I'm familiar with the combined effects of special and general relativity making clocks on GPS satellites tick faster than those on Earth by about 38 microseconds per day. The clocks on the satellites are adjusted to stay in sync with Earth clocks, and all is fine an dandy in that regard...

Homework Statement This is a lengthy problem with 3 parts, so I figured I would keep them separate. I have a diagram that corresponds with the problem as well. GPS receivers find their locations by measuring time differences between EM wave pulses emitted from satellites at known locations and...

I really need help to understand these questions which is highlight, for the GPS situation, I hope anyone who has been working in this situation before, please help me to have a clear understanding about "time delay estimation": Here is the scenario: 1. Suppose I know precisely I have transmit...

hi group, I am working on the GPS data collection, I Need help. If anyone who has been working on the u-blox GNSS Evaluation Kit Time EVK-M8T before and have seen it, please help. I do not know why sudo cat /dev/ttyACM0 only 1 time. I have the U-blox EVK-M8T which can read the NMEA messages...

Can someone explain why the GPS on my phone is improved when Bluetooth is on?

Let's say I have a GPS unit that reports an "accuracy" (this is what the GPS device reports as the uncertainty in the measurement of position) of 15ft. I travel some distance, with the GPS reporting a position every second. At the end of 1000 seconds I arrive at my destination. For the sake...

Hi. Most modern camera quadcopters (drones) have a "follow" function, allowing them to follow and film a person. The DJI Phantom 4 does this by optical tracking, most other brands require that the person carry a smartphone or other wearable. How does this work? I assume the smartphone or...

Although microwaves are not refracted much in the atmosphere, there is some, and the atmosphere does vary a lot, and the GPS depends on a pretty exact timing of the signals between ground to satellite. So how do GPS systems take the atmospheric refraction into consideration?

Hi there! Does anyone know where data from the GPS is available? Any data at all - positions. clock readings anything like that. Many thanks!

Ok, the reason for my absence is I have been working on a project of building a multitasking Robot. Since the connection of Robots to Physics never entered my mind I assumed I have nothing of value to add to any discussion on the PhysicsForums. If anyone is interested in the problem that I am...

This recent article from Ars Technica tells the story of the dangers of relying on GPS for directions: http://arstechnica.com/cars/2016/05/death-by-gps/ Please be careful out there!

Homework Statement The number of GPS units/receivers on smartphones has increased tremendously. Is this going to cause interference? Why? Homework Equations None The Attempt at a Solution I'm not sure if the units only interfere when they are close to each other or what prevents them from...

Hi, I have an interesting problem. I have three GPS coordinates, creating two lines across the surface of a sphere (assuming the Earth is spherical). I want to be able to create a new line (across the surface of a sphere) with a gradient that is in between the gradient of the two existing...

Hi everyone :) I'm working on a Pip-Boy project from the fallout series (making a real life functional one), and I was following the guide of someone who was using a raspberry pi to create it. As I was following along his work, he said that he was having problems with GPS not working indoors...

This just out of curiosity because the system works either way, I just wonder why. I have a high precision GPS system, there are two antennas placed about 2 meters apart with cables that are about 8 meters long going back to an embedded computer. Besides giving you the position, it uses the...

Hi I'm working on a GPS/INS model. Now I developped the mecanization equations for the INS. I have a kalman filter which estimate the error state (position error with respect to north and east). it takes as an input the diffrence between GPS and INS and gives its estimation . I have...

I'm a programmer/electronics student and I recently bought a GPS which I hooked up serially with my laptop. I didn't get into much detail of encoding the string which is output from the TX/RX pins of the GPS so I downloaded, a ready made program called "ublox 6". Longitude and latitude are...

Hi all,as I understand it, GPS satellites are offset prior to launch in order to correct for the time dilation that they experience in orbit. I am very confused about how this works in practice. I think the velocity of a GPS satellite wrt a position on Earth would depend on the position on Earth...

How do GPS Satellites work exactly, with emphasis on exactly. I know that GPS satellites use electromagnetic waves to send out a signal of their current location and time for GPS devices to pick up. Using at least 3 GPS satellites, GPS devices can pin point their location by knowing the...

I can get a measurement of my distance between points (x1,y1,z1 and x2,y2,z2) by analysing position data from a GPS/barometer system, which has a standard deviation of about 2m for x y z positions. I can also analyse data from a system that provides velocity with a standard deviation of about...

Homework Statement What i am trying to do is calcuate the miles used in my car driven a certain distance. Homework Equations What i did was take a GPS unit that takes my position and tracks where i drive by the easting, northing, and alt. I then can put that data on a computer and anlyze...

I have an idea and a small concept of a school bus GPS system that is unique to school buses because it will include recent crime reports in passing areas of concern, weather reports to date, traffic reports to date, and of course the ability to hold multiple destinations at once. With this I...

Hi there, I am not sure if it's the right place to ask the question. My question is how the GPS chooses the best way. I mean where I can find something about its idea Thx

Due to the blogs being removed, I thought it might be worthwhile posting a few in the forums- https://www.youtube.com/watch?v=zQdIjwoi-u4 Time dilation due to gravity (GR)- d\tau=dt\sqrt{1-\frac{2M}{r}} where M=Gm/c^2 Time dilation due to velocity (SR)-...

I need to know how accurate the GPS is on an iPhone. We had guests over this evening and one of their iPhones disappeared. Using the GPS tracker it shows up at a neighbor house two lots down :P

Hi, I am making an NMEA (GPS) signal tracker. (NMEA data is sent from satellites, funcubes plus many more objects e,g, animal tracking) and will be used to aim it's antenna toward the signal for better reception. I assume that this is used for telescope aiming also. The data includes...

The GPS satellite has an atomic clock which sychronizes with the receiver. But when the receiver gets the time, it is delayed as it travelled. So when its 08h 00min 05s in the satellite, the receiver gets maybe 08h 00min 03s. The time of travel of the signal is 2s but how will the receiver...

I figured out differential GPS (DGPS) corrects incoming signal time divergencies resulting from atmosphere and malfunction of sattelites. The station knows its accurate position and accurate position of sattelites -> it calculates the distance from visible sattelites -> ideal signal travel time...

greetings, could you please tell me where i can find information related to gps receiver as i need to use it on my robot. if possible please give the websites where i can get all available gps receiver. i don't know what are the kind of gps available so i m not able to decide... thanks in...