Questions tagged [gps]

stands for Global Positioning System, a satellite based navigation system

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54 views

Tracing GPS antenna on multi layer PCB

I have been tracing PCB for the first time and came to a few questions regarding GPS antenna selection and placement on PCB. Basically, I am trying to make as small as possible PCB with GPS/GSM modem....
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27 views

bluetooth 5 interference from other phones interrupts audio (a2dp and hfp)

(I tried to find the best forum to ask this, here seems the best place; please recommend alternative before downvoting) Problem: while listening to music over bluetooth A2DP profile from a gps (zumo ...
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1answer
49 views

To connect Active GPS Antenna wires on PCBA should Solder or use Connector

Will it make a difference if I solder or use the supplied SMA type connector to connect the wires of Active GPS antenna on PCBA? I am using gps antenna of this type.
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57 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 ...
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1answer
41 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 ...
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31 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 ...
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1answer
71 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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2answers
64 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. ...
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0answers
60 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 ...
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2answers
120 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 ...
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2answers
49 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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45 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 ...
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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
110 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
294 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
338 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 ...
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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?
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1answer
55 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: ...
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1answer
98 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
46 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 ...
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2answers
105 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 ...
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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 ...
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2answers
363 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 ...
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1answer
109 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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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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1answer
38 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 ...
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2answers
98 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 ...
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1answer
177 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 ...
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1answer
105 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 ...
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1answer
247 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 ...
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1answer
127 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 ...
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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 ...
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1answer
79 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
381 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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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 ...
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1answer
52 views

Electromagnetic wave equation for GPS waves

Recently, I came across a source which stated the model of a GPS L1 wave was: My question is, how was this equation derived?
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1answer
131 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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1answer
102 views

GPS L5C Differential? Max Update Rate(bits/s|Hz)?

The differential GPS chips use L1 and L2C to calculate the ionospheric interference. With the new GPS satellites, the new band L5C is being deployed, and I am wondering about the following things: ...
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1answer
56 views

Adafruit 3G Module sends data but don't accept it

I'm having trouble sending commands to the GSM/GPS/3G module from Adafruit. It gives me status data at bootup without any issues (takes a few seconds). The product in use is this: https://learn....
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2answers
187 views

Top Ground Copper pour in PCB having three RF Sections

I am designing my second RF board (First one had BLE). This board has LoRa Components (SX1257 and SX1301), GPS (MAX-6) and 4G LTE Module (SIM7600). All the components are on top layer (red layer). My ...
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3answers
376 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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3answers
867 views

gps performance for synchronization

I can't understand why GPS reciever clock is very good (stratum 0). I know it's very accurate and pure within itself; but when it passes through a long distance wireless channel, then it has low power ...
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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, ...
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1answer
423 views

Selecting DC Blocking Capacitors for GPS, LoRa

I am designing a transmitter and receiver part of LoRa and GPS. It requires DC Blocking capacitors. I was looking for capacitor over digikey and I am amazed most of the manufacturer haven't specified <...
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1answer
42 views

GPS start mode query

I am using SIM808 GPS/GSM module. I came across Cold start,Warm start and Hot start in GPS Modules while developing code for a GPRS Tracker for car. I know the difference between them.My question is ...
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1answer
216 views

Why DC block is used for GPS receiver tested using a simulator via an active antenna?

Reading up GPS testing using a simulator and came across several articles which suggest requiring a DC block capacitor in the RF path between the GPS Simulator+Attenuators & Active Antenna. Some ...
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1answer
91 views

How are antenna arrays synchronized for direction finding/localisation?

How are antenna arrays synchronized for direction finding/localisation? For example, if the processing unit is located closer to one antenna then another, it will see the signal from the closer ...
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1answer
109 views

convert Ascii value to Binary or text

I have a GPS Tracker that connects and send data to a defined public server: port through GPRS connection. I am getting the result on the terminal. I have provided with a manual. I don't understand ...
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1answer
122 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 ...