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Questions tagged [gps]

stands for Global Positioning System, a satellite based navigation system

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0answers
21 views

GPS Fix but Pulse-per-Second Inop? [on hold]

I'm using a UBlox MAX-M8Q interfacing with an XSens MTi-7 Inertial Measurement Unit. Antenna is a Tallysman 33-2920, which I believe has a slightly higher noise figure than is spec for the MAX-M8Q. ...
0
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2answers
43 views

Lithium ion (Li-ion) vs. Lithium thionyl chloride (LTC) battery?

I need some consultation on which battery of the two to use for the GPS trackers I'm designing. My trackers wakeup when there's movement only so they're not on all the time and they have low power ...
0
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1answer
155 views

Is a voltage level shifter necessary?

I am using an STM32F100xx MCU and I want to communicate via UART with a GPS module, specifically the A7 Thinker GPS GPS Module with A7 Thinker from Aliexpress This module, when a 9V battery is used, ...
1
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1answer
40 views

General open license PCB GPS antenna

Is there a basic passive GPS reference antenna design that would be considered fair-use or "free to use" that can be placed on a PCB as a strip antenna or patch antenna? I'm looking not to violate ...
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2answers
39 views

How to sync GPS time and pulses of micro-controller

I have two of the devices (a while loop in the code) that need to start at the same time, within 50ms or less of each other. Each is using the same GPS module, and I am using "ARM® Cortex®-M3 Giant ...
2
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3answers
355 views

Why does Lidar have GPS, serial, and PPS input?

Many commercial Lidar systems have GPS, PPS, and serial interfaces. What's the application and how's it being used?
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0answers
29 views

Does feedline of through-hole antennas have to be at the bottom?

Does feedline of through-hole antennas have to be at the bottom of the PCB or is it ok to have it on the top? I don't see why it can't be on the top but I read in Taoglas docs that it should be on the ...
0
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1answer
69 views

Bigger GPS antenna better or more efficient?

I have the choice between: 1) 35x35mm GPS antenna 71% efficiency glonass, tested on 70x70 GND plane 60% gps 2) 25x25mm GPS antenna 83% GPS, 84% glonass, tested on 50x50 GND plane I have read ...
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0answers
347 views

What kind of GNSS antenna is this?

I would like to know what types of GNSS antennas are on the images below (patch etc.) and also which one is better from the two (if any). They are being sold as "high precision" survey grade antennas. ...
3
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1answer
394 views

GPS - Noise Figure Analysis

I am trying to analyze all components in one home-made GPS receiver and I am stuck with figuring out how to determine Noise Figure at the mixer output. See picture below: If we are going from the ...
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2answers
61 views

Software vs hardware-defined GNSS receivers

I am conducting research into the accuracy of smartphone positional fixing accuracy. I have come to understand that smartphones use software-defined receivers rather than hardware-defined receivers. ...
0
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1answer
129 views

Which Board Should I Use For High Frequency GPS? [closed]

This is a very general question, hopefully with the amount of information I provide you will be able to steer me in the right direction. I am trying to build a very versatile GPS receiver, with ...
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0answers
58 views

GPS PCB RF Design and Performance Impact

I have designed a vehicle tracker for two-wheelers which is installed in 500 bikes. I am facing an issue with GPS performance (lock percentage is quite low for more than 75% bikes). This makes me ...
2
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2answers
93 views

RF - sma pth connector impedance matching to cpw

I am designing a 4-Layer PCB with an SMT GPS/GNSS receiver (1575.42 MHz), where it connects to an external antenna through an SMA Connector. I have already done all the calculations of CPWG using ...
3
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0answers
96 views

Running Application on SIM808 GNSS module beside it's internal firmware

I'm trying to load my written program to SIM808 and the module will be responsible for running my program and also its internal firmware. SIMCOM has a document about doing this in SIM800 module but ...
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2answers
44 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 ...
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0answers
43 views

GPS and Galileo signal reception with a broadband antenna

I have a passive antenna that covers a wide bandwidth (1.25 - 2.45GHz, RHCP, omnidirectional) which I'd like to re-purpose for Galileo signal detection. I don't have an option to get an application ...
4
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1answer
118 views

Inductor for a GPS active antenna

I have been testing the GPS / GPRS development module A9G, Aithinker which uses an active GPS antenna, according to the schematic reference diagram, the value of the inductance is 82nH: The question ...
9
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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 ...
0
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1answer
108 views

REYAX RYP820U mPCIE (actually USB2) GPS/GLONASS/BeiDou module and PPS

So, I thought I might try to set a time server (as one does). I have a nano ITX mb with a mPCIe slot on it, and I found a GPS card that supposedly outputs a 'timepulse'. It was cheap enough that I ...
3
votes
2answers
865 views

customize server in GPS Tracker

Is there any GPS tracker available in which I can set server's location (some IP) to which that device will send notifications (GPS data). I want to create my own GPS receiver server.
0
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1answer
216 views

Manufacturers' recommendations for ground plane for GPS patch antennas

I see requirements for specific ground plane sizes in many GPS antenna datasheets, but I also see many devices that ship with significantly smaller ground planes. Do these integrators know something ...
1
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2answers
40 views

assited gps vs differential gnss [closed]

i am writing as essay evaulating accuracy of smart phone gnsss for GIS data collection for part of the essay i thougt it appropriate to mention DGNSS and Assisted GNSS. So far i understand Assited ...
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3answers
108 views

1PPS vs high resolution timer in CPU

We need to use 1PPS (pulse-per second) in our standalone system which is based on arm processor, and has cameras input. The 1PPS is implemented with GPIO which is injecting an interrupt (low to high)...
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2answers
179 views

PCB layout for chip antenna

I recently made my first PCB. I ordered it from China and soldered it up on my homemade oven, and it's working awesome. I've already started a list for rev 2. There is one issue that I'm hoping I ...
2
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2answers
219 views

How to use 1PPS to Synchronize ESP32 Clocks and Peripherals

I've read a few posts (example) about what the 1PPS signal is and how it can be used at a high-level, but I'm still not sure how to actually implement it on a PCB schematic to sync up with my ...
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1answer
276 views

Lithium ion battery how to connect to PCB? [closed]

I'm planning to use lithium ion batteries to power GPS trackers PCB that I've designed. I'm struggling with how to connect it to my PCB both as a final product and for prototyping? Also are there ...
3
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2answers
1k views

Why is there a diode on the RX pin of the Adafruit Ultimate GPS board?

I can't seem to understand why there is a diode at the Rx pin on this Adafruit Ultimate GPS board. If we are sending data to the GPS, why put a diode that prevents current flow into this pin?
2
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2answers
243 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
50 views

Voltage Regulator for GPS vs. BMP280

I am using the Bosch BMP280 pressure sensor and the FGPMMOPA6H GPS chip together on a PCB. I am using the reference designs from Adafruit's breakout boards for each chip (found via the product links: ...
0
votes
2answers
80 views

does adding Vias through the antenna feed line change impedance?

I have a GPS through-hole patch antenna, the through hole need to be connected to the bottom layer and then from there the feed-line flows to the GPS receiver. But I want the GPS receiver to be on top ...
0
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1answer
80 views

Struggling with patch gps smd antennas connections

I'm struggling with antenna connections to GPS module in my PCB design. My antenna is a smd passive patch antenna, "SGGP.25.4.A.02 from Taoglas". The antenna shape and recommended footprint is in the ...
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0answers
44 views

Input and Output Impedance of a SAW Filter

I am reading the datasheet of a SAW Filter B39162B4348P810. The datasheet doesn't say much about impedance of Input and Output ...
39
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3answers
7k 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,...
0
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1answer
100 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 ...
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0answers
11 views

What is a difference between peak gain & avarage gain of an Antenna? How avarage gain is measured?

What is a difference between peak gain & avarage gain of an Antenna? How avarage gain is measured? For an antenna (e.g. GPS chip antenna) if avarage gain & peak gain given, which value should ...
3
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3answers
362 views

Are Civilian GPS signals cryptographically signed?

As far as I understand, receiving enough GPS signals at the same time enables to deduce the position and the time. So I guess it is possible to use an offline receiver as a very precise clock? If so,...
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2answers
61 views

Can I use MCU's internal oscillator when communicating with GPS and cellular modules?

Can I use MCU's internal oscillator when communicating with GPS and cellular modules? I want to avoid connecting external crystals for the MCU since they generate noise, extra components, extra costs, ...
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2answers
568 views

Dual GPS Antenna Connection to Positioning Module

I am using a Positioning module that has a SMA port to hot plug an SMA antenna. It also has pins available through its footprint to connect a GPS Antenna. The module name is SIM908. I was not able to ...
0
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1answer
36 views

How much computing power is required for a GPS Device/Station That Uses L1 and L2C Frequency to Calculate For Ionospheric Delay-Interference? [closed]

I’ve been trying to find GPS chips or devices that receive L1 and L2C and from a quick google search they seem to be very professional equipment, very bulky with huge antennas. This makes me wonder ...
73
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5answers
34k 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 ...
1
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2answers
625 views

NMEA via RS232 and PPS (TTL) splitter

I have GNSS device that outputs NMEA messages via RS232 PPS signal via a digital out (TTL) I need to distribute both the RS232 and the PPS signal to more than 1 system (currently 3, but could be ...
0
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2answers
88 views

GPSDO in firmware?

There are numerous designs online for hardware GPSDO (GPS-disciplined Oscillators). I'm failing to find any firmware-only implementations. I wonder if my Google foo is weak or if these are impractical ...
0
votes
1answer
160 views

Effects of Neodymium magnets on PCB

I'm currently doing a project that consists of: Arduino Nano. Battery. Buck Boost converter. GPS module. TSL2561 light sensor. BH1750FVI light sensors. LSM6DS3 Accelerometer. HDC1080. MicroSD shield ...
2
votes
1answer
94 views

GPSDO control algorithm

I am currently building my own GPS disciplined oscillator. I have a OCXO which is used as clock source for a microcontroller and one of its counters, and the 1PPS signal from the GPS module is ...
0
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1answer
46 views

Locating mobiles/UE by base stations in a cellular system [closed]

After understanding a bit about how actual cellular systems function, I realized that identifying the mobile/UE location is key in assigning the UE to correct base station and thus to guarantee a ...
1
vote
1answer
113 views

Adafruit Ultimate GPS sendCommand

EDIT: Solved, Problem was with not sending "\r\n" at the end of the sentence. I'm trying to control Adafruit Ultimate GPS through STM32F407, there is an official Arduino Library and this library has ...
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1answer
78 views

Would it be energy efficient for phones to include actual GPS chip? [closed]

None of the smartphones today have dedicated GPS chips in them, they only have a GPS capability that stems from byproduct features of the modem chips. Because of that, the GPS capability is very ...
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3answers
2k views

SIM908 GPS STATUS “Location Unknown” Error

I'm using a SIM908 module on a custom board and am having trouble getting the GPS location from it. Everything else works on the module. I can send SMS, make calls and send and receive data from a ...
15
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1answer
2k views

Official GPS protocol documentation?

Searching for "GPS protocol" reveals many sources for processed GPS data, e.g. NMEA or binary outputs of GPS units. Where is the official documentation for the GPS satellite - receiver protocol? Or ...