Read about gps | 19 Discussions | Page 1

  1. M

    Global Positioning System / Clocks in Space

    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 earths movement, can I also neglect the movement of the satellite with respect to the far away observer? If so, I...
  2. P

    I GPS relativity error - really?

    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...
  3. T

    B Why does GPS require an accurate clock?

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

    Insights The Schwarzschild Metric: Part 3, A Newtonian Comparison - Comments

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

    Insights The Schwarzschild Metric: Part 2, The Photon Sphere - Comments

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

    Meaning of cryptographic GPS signal

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

    Online video lectures about principles of GPS?

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

    Understanding time delay estimation for GPS?

    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...
  9. N

    Why “sudo cat /dev/ttyACM0” run only 1 time? (GPS)

    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...
  10. G

    Technology behind camera drones with "follow" function

    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...
  11. nomadreid

    What does GPS do about atmospheric interference?

    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?
  12. M

    I GPS data

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

    Geometric GPS

    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...
  14. P

    If GPS works on timing why doesn't having a cable ruin it?

    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...
  15. R

    GNS/INS (Inertial Navigation System) integration

    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...
  16. J

    How do GPS Satellites work exactly?

    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...
  17. 9

    Two measurements from different sources - how to combine?

    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...
  18. T

    Calculate MPG with GPS

    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...
  19. Hunter Brandon

    School Bus GPS

    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...