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Questions tagged [gps]

stands for Global Positioning System, a satellite based navigation system

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Would two antennas on the same board work well?

I'm building a circuit based on Nordic´s nRF91, my project involves making a compact solution for acquiring location, having to fit it to a small enclosure I'm thinking about making a board for both ...
DMinatto's user avatar
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14 votes
2 answers
5k views

Which signals (Wi-Fi, mobile phone, and GPS) can reliably be blocked by aluminum foil?

There seems to be conflicting information regarding which signals can be effectively blocked by wrapping the device in aluminum foil. With effectively blocked I mean block the signal as such that the ...
CuriousIndeed's user avatar
8 votes
5 answers
2k views

Changing output impedance of a logic gate to 50 ohm

I making a simple circuit to take 10 MHz output from a GPS module and calibrate a frequency counter with this 10 MHz signal. I have already found a circuit designed by radio amateur ZL2PD. Circuit ...
Ashok Das's user avatar
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0 votes
2 answers
77 views

GPS fix with plastic lid closed [closed]

I have a product where I'm using Adafruit Product 746 (Ultimate GPS Module - 66 channel w/10 Hz updates - PA1616S - MTK3339 Chipset). I'm using this external active GPS antenna "32db High Gain ...
vicatcu's user avatar
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1 answer
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Why do different GNSS receivers show different measurements on the same satellite?

I have two receivers + antennas pairs where I collect data from. So, each receiver outputs one RINEX file where I can look at the epoch-by-epoch measurements of pseudorange, carrier and doppler. Why ...
Myron Phan's user avatar
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0 answers
40 views

Generating sine, triangle (etc) waves from ttl output of a GPS module (Ublox)

I'm building a variable frequency standard using a Ublox gps board off Ebay. It'll be hooked up to an Arduino and you enter the desired frequency via a keypad. The signal from the module is a square ...
Mandelstam's user avatar
0 votes
2 answers
64 views

Rechargeable batteries on GPS dev boards and how is it getting charged?

Almost all of the GPS dev boards have a tiny button/coin battery (for hot startup) and the specs claim that is it rechargeable using a simple diode and register circuit. Here are a couple of examples ...
John Watt's user avatar
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0 answers
67 views

SMD IC Marked 18R ID Help

I need help identifying a 6 pin IC marked 18R, thanks in advance! Additional Info Dimensions: ~1.6mm x ~1.6mm Pitch: ~.3mm Connected to the VDD pin of the ICM-20948 9-Axis MEMS Motion Tracker Other ...
Elliott's user avatar
  • 21
3 votes
1 answer
301 views

Inductor on a GPS receiver

I'm soldering the circuit of a high accuracy (and cost) GPS receiver with an active antenna. The inductor L1 in this diagram has a polarity marked by a dark band on one end. Which side do I put the ...
Tim's user avatar
  • 345
6 votes
1 answer
788 views

10MHz reference vs 1 PPS vs GPSDO

In the context of Software defined radios (SDRs), what are the differences between using an external 10MHz reference versus using a GPSDO? Why/when would you use one over the other? And how does the ...
BigBrownBear00's user avatar
2 votes
1 answer
112 views

Reducing lock time for Sim A7672E GNSS unit, through improved antenna

I'm utilizing the RF module A7672A for GNSS positioning, aiming to identify the optimal antenna configuration to achieve the shortest TTFF in a compact PCB design, preferably using an SMT antenna. ...
Anthony J Feghaly's user avatar
0 votes
1 answer
71 views

What is the actual physics and reasoning for the “Ground plane” underneath a GPS patch antenna

From my very limited knowledge of EM, I believed that anything tied to earth can absorb radio waves, so if an antenna was to be placed above a ground plane, why does the ground plane not just absorb ...
George kirby's user avatar
0 votes
1 answer
244 views

Ferrite Bead for Ublox M10S GPS unit

I am trying to understand what ferrite bead to use for the Ublox M10S GPS unit. I am using as a reference the design from SparkFun GNSS Receiver Breakout - MAX-M10S (Qwiic) (https://www.sparkfun.com/...
Enk73a's user avatar
  • 1
0 votes
1 answer
130 views

Powering a pico with a lipo battery charged by a bike dynamo

I am building a GPS tracker build on Raspberry Pi Pico and a u-blox NEO-6M GPS module. Now, I want to power this project with a lithium battery that can offer some autonomy. I was thinking of using a ...
Edoardo Balducci's user avatar
1 vote
0 answers
69 views

Switch Mode Power Supply / GPS - Filtering+Shielding

I'm working on my first RF PCB, for GPS/ GNSS and am particularly concerned about Noise/ Interference. Hopefully someone can shed some light, or point me toward a similar thread? It's worth noting ...
MightyBenster's user avatar
2 votes
2 answers
383 views

Can you do without a base station for RTK GPS if only relative positioning is needed?

I am trying to take two drones in an open field and have them know precise and accurate relative positioning of each other. I don't need them to actually know where they are. My plan is to use some ...
wandy rge's user avatar
1 vote
0 answers
161 views

Raspberry Pi Pico powered by a bike dynamo

I am building a GPS tracker for my bike using a Raspberry Pi Pico and a NEO-6M GPS module. I need this GPS to be up and running at least 14 hours a day. The only problem is the power source. Ideally ...
Edoardo Balducci's user avatar
1 vote
1 answer
208 views

GPS signal combiner

I want to use WP4N+ as a GPS signal combiner with NEO 6M receiver. Here is my schematic. On power on, resistor 22 Ω is getting VERY VERY HOT and I do not receive any signal from the satellites. ...
Alatriste's user avatar
  • 160
0 votes
0 answers
30 views

Why am I getting incomplete geolocation data for long periods of time using SIM7070g?

I'm facing a problem while working on a tracking application using the SIM7070G module for GNSS data. The application alternates between sending data and retrieving GNSS coordinates due to SIM7070G ...
Santiago Mercante's user avatar
7 votes
5 answers
2k views

Can I improve the GPS accuracy by choosing a different antenna?

I am currently looking for an antenna to determine GPS location. The question is a general one, but I have listed the equipment that I am using to help ensure that answers are more likely to be ...
cobdmg's user avatar
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0 answers
56 views

GPS 4-layer stackup

I'm developing a GPS module with passive ceramic patch antenna, I need suggestions if the following 4-layer stackup I've chosen might work: Top layer has the ceramic patch antenna and a status LED, ...
Dave84's user avatar
  • 11
1 vote
0 answers
31 views

How transmit and receive work from the same antenna and pin for RFD900?

I'm currently using the RFD900 SMD version for an avionics bay for long range GPS capabilities. I have read the datasheet and saw this: The RDF900ux(-SMT)/868ux(-SMT) modem has two antenna ports and ...
Lucas Webb's user avatar
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0 answers
52 views

Receiving Timestamps from PPS using uBLOX MAX M8C-0 GPS Receiver

I am having problems with sending and receiving the messages. I am using the SDA and SCL lines. My goal it to try to use the PPS to get under 5 millisecond accuracy for timestamp purposes. Could ...
jmoffett's user avatar
2 votes
0 answers
103 views

Best way to close GPSDO PLL digital loop?

I am trying to build a GPSDO with a holdover capability of 500us/24hs (maximum drift accumulated). The system uses a 10MHz OCXO and it is my intention to use a microcontroller (ATMega, STM or ...
Fernando Hernandez Ruiz's user avatar
0 votes
0 answers
249 views

GPS/GNSS standard active antenna voltage and current draw

I'm designing a GNSS receiver that I'd like to be compatible with a variety of different active antennas. What antenna voltages are possible, and is there any (unofficial) standardization of this? I'...
MattHusz's user avatar
  • 1,053
0 votes
1 answer
99 views

What's the purpose of VCC_RF for u-blox ZED-F9T GNSS receiver?

The ZED-F9T, and presumably other u-blox GNSS receivers, can power an active antenna with a VCC_RF pin. The VCC_RF voltage is specified as being essentially the same as the module voltage (VCC) (...
MattHusz's user avatar
  • 1,053
0 votes
0 answers
70 views

SIM808 module does not get GPS location

I am trying to use a SIM808 module to get a GPS location, but it does not work. My power supply can provide up to 5A. The picture results from my communication with the SIM module using the AT command....
trungvann's user avatar
1 vote
1 answer
65 views

Can the PA1616D GPS module connect to a backend server to send GPS updates to a mobile phone?

I am building an IOT device that will be moving around outdoors and will not be able to have a secure wifi connection. I want to be able to know the location of this device at all times on my mobile ...
Trev347's user avatar
  • 1,072
1 vote
1 answer
141 views

How to set the output frequency for the PPS pin on the CD-PA1616S GPS module? (Used in Adafruit Ultimate GPS board)

The datasheet says you can change the freqnecy... 1.5 1PPS A pulse per second (1 PPS) is an electrical signal which precisely indicates the start of a second with the accuracy of ±20ns RMS (Root Mean ...
bigjosh's user avatar
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2 votes
2 answers
176 views

Why are there LC filters on the UART line to the M20050-1 GPS module?

I am designing an IoT device. In first version, I forgot to put the LC filters as in the datasheet. I found it after I get the prototyping board on my hands, but I thought it would be fine without ...
PCBCrew Engineer's user avatar
0 votes
1 answer
85 views

Why is civilian GPS symmetrically encoded?

Why is civilian GPS information symmetrically encoded? It is encoded using symmetric MAC, with the MAC key also being broadcast. This seems completely pointless. Why don't they use private/public key ...
zeb3142's user avatar
1 vote
0 answers
78 views

What's the deal with different size GPS antennas?

I have some GPS modules laying around and I noticed they're pretty different size to each other. (here are two of them for example): So doesn't any antenna have to be a specific size for a given ...
floppydisk's user avatar
1 vote
1 answer
56 views

Confusing antenna datasheet (feed points)

I'm looking at the TDK ANT016008LCD1575MA1 for a GPS application. It has two pads for radiator electrodes (which is for tuning/matching capacitors). But it's confusing about the four feed points. It ...
okwestern's user avatar
0 votes
0 answers
312 views

What attenuator to use for using HackRF one to simulate GPS for in production testing?

I am trying to use the HackRF One to simulate GPS to test devices in a production environment. I am currently able to get the GPS signal on my GPS receiver that I am testing, but the signal is much ...
mgwalker95's user avatar
1 vote
1 answer
169 views

NEO-M8N Microstrip Line Calculator

I am designing a pcb which has the module ublox NEO-M8N, However I am having trouble calculating trace widths. I am planning to use an FR-4 board. I was using the following calculator to try and ...
RACHID BEN ABDELMALEK's user avatar
2 votes
0 answers
688 views

USB 3.0 noise blocking GPS signals

We have designed a compact system that has: Custom processing unit with USB phy and a USB 3.0 HUB (usb5744) with custom plastic USB connector. USB 2.0 wifi module(external peripheral connected with ...
Tomin Jose's user avatar
0 votes
1 answer
119 views

What are this components on uBlox EVA M8M GPS?

I am designing my own pcb board based on a Sodaq One V3 (I built my prototype with a Sodaq One V3 and a MAX30102) and I am currently integrating both devices in KiCAD but I have a doubt with the GPS ...
imt_blake's user avatar
  • 441
3 votes
2 answers
530 views

How can a GPS receiver estimate position faster than the worst case 12.5 min it takes to get ionospheric model parameters?

Consider a single-frequency GPS receiver. On the legacy L1 C/A signal, the receiver will over the course of an entire navigation message (12.5 min) get the model parameters for the ionospehric ...
Curious's user avatar
  • 41
0 votes
3 answers
649 views

Could multiple transmitters on the same frequency work if phase-locked to GPS? (gedanken)

I've been noodling this concept for a while; it seems to me that if it were actually workable somebody would be doing it already, but I haven't heard of it happening. So where do I go off the rails ...
Crash Gordon's user avatar
  • 1,268
2 votes
0 answers
486 views

GPS Active vs Passive SMD antenna

I'm designing a tiny wearable device that is characterized by a plastic case. It contains the PCB and the battery (Lipo). I'm struggling a lot with the GPS antenna because I must use a small SMD ...
RodEnry's user avatar
  • 21
1 vote
1 answer
127 views

Problem with GPS old location [closed]

I wrote a GPS driver which sends and reads AT commands. I send the AT+CGPS=1,1 command to get the GPS location and if there is no answer I send ...
aguero's user avatar
  • 21
14 votes
1 answer
831 views

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 ...
Neil Forrester's user avatar
1 vote
2 answers
144 views

Sharing multiband antenna between ICs

I am working on a ultra low power project where portability and low weight is important. The circuit would have multiple ICs, that need to communicate over multiple frequencies: Esp32 - WiFi/Bt 2.4 ...
Márton Kéri's user avatar
0 votes
0 answers
103 views

Mediatek MT3333AV doesn't start

Recently I started a project with an MT3333AV GPS IC. I desoldered the chip from the L86 GPS module and put it into my project. After many tries I still can't start the IC. There is no 1.1 V going ...
kronikary's user avatar
1 vote
0 answers
73 views

Reverse trilateration / multi-lateration using BLE Beacons

I'm currently working on a proof-of-concept to work out the estimated locations (longitude and latitude) of outdoor beacons with unknown locations to begin with. The solution will use a mobile ...
LawrenceH's user avatar
  • 111
0 votes
0 answers
69 views

Why do some GPS modules in smartphones have two or more antennas?

Some GPS modules have only one antenna, but some of them have two and more. For what? Are they made for different frequencies and ranges?
HeatherAle's user avatar
0 votes
1 answer
52 views

How to detect if a user has gone past certain locational boundaries physically [closed]

I want to write some software that takes the location of a user's phone and makes sure it is within a certain boundary that is set by "invisible fences"; see the picture below. What kind of ...
isaiahstanke's user avatar
3 votes
1 answer
221 views

Do I need via shielding for the GPS antenna trace?

I'm working on a 4 layer board (signal, GND, PWR, signal). I have a NEO-M8P GPS module and the Hardware integration manual says to connect the antenna with a 50 ohms impedance trace to the connector ...
Rodo's user avatar
  • 1,130
0 votes
2 answers
202 views

Do I need a GPS simulator to design a device that contains a GPS receiver and a pre-designed antenna?

I have designed a device using an STM32 Nucleo board, a GPS module, a GSM module, some discrete components, and a bread board. It is a sort of a car tracker. I have decided to design my own custom ...
illidan's user avatar
2 votes
1 answer
149 views

Noise factor in homemade software-defined GPS receiver

I'm building a homemade software-defined GPS receiver. I'm currently at a point where I can acquire and track strong signals but struggle to even detect weak signals. I've ruled out problems with my ...
Manuel Menzella's user avatar

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