Electrical Engineering Stack Exchange
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Questions tagged [gps]

stands for Global Positioning System, a satellite based navigation system

Further reading:

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Why does smartphone GPS find its position much faster than a GPS module?

When I'm using the arduino GPS module it usually takes a couple of minutes for it to start sending data. And it seems that it's usually the case with all GPS modules since they need to "listen" to the satellites for some time. However whenever I use…
Anthropomorphous Dodecahedron
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How many GPS channels make sense?

You need 4 channels to determine your position (including elevation), and I can understand that a few extra channels increase accuracy. However, there are maximum 12 satellites in view at any time, so why have receivers with more channels? I've seen…
stevenvh
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Why do GPS receivers have a 1 PPS output?

I was surprised to see that the GPS receiver I'm working with has a pin reserved for outputting a 1 PPS (Pulse Per Second) signal. What is the point of this? Can't the microcontroller easily generate its own 1 PPS signal?
Randomblue
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GPS pulse/s not aligned with reported times (u-blox ZOE-M8Q)

For the sake of fun and learning, I'm trying to make the most accurate wall clock I possibly can, driven by GPS. I'm starting with a u-blox ZOE-M8Q breakout board I got from SparkFun, and a Raspberry Pi Pico microcontroller. At a glance, things…
Neil Forrester
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GPS: 12 satellites in view but no fix

I have a Jupiter F-2 GPS receiver connected to an STM32 that outputs NMEA messages every second. The GPGSV message indicates that I have 12 satellites in view. At the same time, the GPGSA messsage indicates that I have no fix, either 2D or…
Randomblue
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How does the GPS scale and deal with potentially millions of requests per second and respond in real time?

Nowadays almost everyone who have owned a smartphone or some type of GPS device somewhere. These devices also seemly update in real time. How is the GPS satellite capable of responding to potentially millions of requests from millions of different…
user10037
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GPS for Cubesats - is 8km/sec too fast for consumer chips?

Satellites in low earth orbit are moving close to 8km/sec. Most consumer-grade GPS chips still invoke the CoCom limits of 1000 knots, about 514 m/s. CoCom limits are voluntary limits for exports that you can read more about in this question and…
uhoh
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66 GPS channels for 22 satellites - why the factor of 3?

Modern GPS chips can use signals from many satellites at the same time to obtain a solution. While typically 4 are necessary, a larger number helps improve the solution with some types of errors. As an example for this question, the Adafruit…
uhoh
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GPS Units - Weather Balloon

I have a problem concerning GPS units. I have been studying on a project for a weather balloon which will go about 30 - 40km up. Now I do know that some GPS units have a limit on how high they can receive/show you the location whether it is a…
avitex
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how is the 1PPS signal generated in GPS receivers?

The question might seem stupid, but the time of flight from the satellite is unknown and moving, the doppler effect is skewing the frequency (and is not constant due to the relative trajectory) and satellites are constantly coming and going to view,…
nraynaud
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Receive GPS Antenna and cable simple confirmation of operation

I am in need of testing a GPS antenna and cable assembly after installation at a reasonable cost. I have a GPS antenna installed on an airplane, then the coax cable from the antenna goes down to the receiver. The system is already assembled and…
Bill Tilman
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GPS Suggestions

I have decided to play in the world of GPS modules. I have read the GPS Buying Guide from Sparkfun, but still am not sure which unit I want to go with. I am leaning toward the LS20031, do any of you have any experience with GPS modules? Any advice…
Kellenjb
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GPS PPS signal corresponds to data time?

I currently have an Adafruit Ultimate GPS connected to an Arduino that outputing GPS data (nmea sentences) once per second. There is also a pin on the GPS outputting 1 PPS signal. My question is whether the pulse of the PPS suppose to match the…
Lightsout
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What is the major technological change that has dramatically improved GPS acquire time?

What has allowed us to go from a unit (eTrex for example in year 2000) that would take many minutes to acquire GPS lock and be unable to do so indoors, to a modern android phone that will lock in a matter of seconds even inside on the ground floor…
Keith
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GPS positioning faster than 1Hz

I am a systems engineer working with various instrumentation devices for ground platforms. These platforms can vary in speed from 0-60+mph. Current instrumentation provides TSPI at 1Hz and is based on GPS. We are looking at a new system that claims…
DJGlover7
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