Questions tagged [gps]

stands for Global Positioning System, a satellite based navigation system

Filter by
Sorted by
Tagged with
77
votes
5answers
35k views

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 ...
9
votes
6answers
14k views

Resistors in series with Tx and Rx

I'm making my own board and using an ATmega 328 with the Arduino bootloader. I have a DIP switch to select either an FTDI chip (for programming) to be connected to the ATMega's Rx and Tx, or a GPS ...
3
votes
6answers
3k views

Indoor Location Positioning

We are developing a mobile application for smartphones (Iphone, Android, BlackBerry, etc) and want to allow navigation at indoors. We can buy and place indoor gps antennas but will this solve our ...
13
votes
13answers
11k views

What can I use to detect pinpoint location (inches) outdoors?

I am getting back in to EE after some time so please excuse my ignorance. I am looking for a way to detect pinpoint location outdoors to navigate a robot for a project with my sons. Is there a low ...
1
vote
2answers
6k views

Use of the GPS 1PPS feature in a system

I'd like to know how synchronization between the GPS unit and any other sensors is done in a typical system. I understand that the 1PPS signal plays an important role. Could anyone give me a very ...
40
votes
3answers
8k views

How do GPS satellites refresh their clocks

How do GPS satellites keep their on board clocks accurate? I assume that they need to get update from a base station. But how do you make sure that after the update all the satellites are synchronized,...
8
votes
5answers
2k views

GPS QA during manufacturing

Testing and integration engineers on electronics.stackexchange How do you quality check if a GPS module and its subsystems are up to the mark during manufacturing? ...
13
votes
1answer
4k views

GPS Design Review (RF Input)

I've designed a PCB in Eagle to host a GPS Receiver module and a GPS patch antenna. The RF input to the module is specified as a 50Ω unbalanced (coaxial) RF input. I used this calculator to calculate ...
9
votes
3answers
2k views

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 ...
9
votes
5answers
665 views

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 ...
0
votes
1answer
137 views

How to detect potentially poor antenna placement from GPS data?

Below is data from a 6.5 hour run collecting NMEA sentences from a u-BLOX NEO-6 GPS module (datasheet, protocol spec) with an active external antenna via Raspberry Pi. This is my first analysis to ...
7
votes
2answers
2k views

Can I “integrate” the data from an accelerometer to record a motion trajectory?

I would like use an accelerometer equipped device to record a motion trajectory, as high-resolution and low-noise as possible. For instance, let's say I run a jogging route of 6 kilometres, returning ...
5
votes
2answers
845 views

How does GPS calculate time

How can a GPS device give exact timing even when the number of available satellites are zero? I'm monitoring GPS data using VisualGPS.
4
votes
3answers
3k views

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 ...
3
votes
3answers
507 views

GPS Almanac versus Sky Search

The total almanac data is transmitted in 25 navigation messages. Each navigation message takes at least 30 seconds to transmit. So, receiving the almanac data from the satellites takes at least 12.5 ...
3
votes
2answers
338 views

Disciplined oscillator using counter+micro

I am working on implementing a disciplined oscillator to increase the accuracy and long-term stability. The oscillator would be a VCTXO running at about 25 MHz. My thought is to have a 32-bit counter ...
2
votes
2answers
142 views

Inaccuracy in the GPS data

How can I get the inaccuracy associated with the GPS data. For example when I read lat, lon, speed, heading data from a GPS receiver, how can I get an approximation on the inaccuracy that is ...
2
votes
2answers
640 views

What exactly does C/No (dBHz) mean in u-Blox GPS data?

In this related question I show data collected from a 6.5 hour run from NMEA sentences from a u-BLOX NEO-6 GPS module (datasheet, protocol spec) with an active external antenna via Raspberry Pi. I'm ...
1
vote
1answer
353 views

GPS pinning parameters

I have a Venus634LPx GPS on a breakout board from SparkFun. The documentation is very cryptic, so I did not manage to configure it manually through the UART (although I can read data from it). ...
0
votes
4answers
659 views

Voltage decreases on higher current

I have a circuit composed of Arduino Mini Pro 3.3V and GY-GPS6MV2 (GPS Ublox NEO-6M). I have tried to power it with 3 different sources: 3xAA NiMH in serie connected to RAW pin of Arduino and using ...
0
votes
2answers
56 views

coplanar waveguide vs microstrip for gnss and cellular?

coplanar waveguide vs microstrip for gnss and cellular? I read on internet microstrip is better for signals <30Ghz but some gps manufacturer (Delorme) said that coplanar is most efficient so it's ...