Questions tagged [gps]

stands for Global Positioning System, a satellite based navigation system

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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 ...
3
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2answers
890 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.
1
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2answers
49 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 ...
0
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3answers
151 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)...
0
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2answers
419 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
757 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 ...
-4
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1answer
1k 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 ...
4
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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?
3
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2answers
3k 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 ...
0
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1answer
227 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 ...
0
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0answers
64 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 ...
40
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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,...
5
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3answers
496 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,...
0
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2answers
66 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, ...
1
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2answers
657 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
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 ...
1
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2answers
1k 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
173 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
591 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
243 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
votes
1answer
55 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
186 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 ...
-4
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1answer
84 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 ...
0
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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
votes
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 ...
1
vote
1answer
62 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?
6
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1answer
126 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: ...
3
votes
1answer
788 views

What is the meaning of the term “Ground Paddle” in the context of ORG1411 PCB design?

I am designing a breakout-board style PCB for prototyping an ORG1411-PM01 module and am unsure about how to meet the datasheet's layout recommendation for the "ground paddle"? The Reccomended PCB ...
0
votes
1answer
59 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....
3
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2answers
384 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 ...
6
votes
3answers
1k 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 ...
1
vote
1answer
664 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 <...
0
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1answer
53 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 ...
1
vote
1answer
398 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 ...
1
vote
1answer
126 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 ...
0
votes
1answer
135 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 ...
5
votes
2answers
22k views

Using a GPIO pin as a power source

I have an STM32F2 (reference manual here) which is connected to a GPS receiver through 5 pins. One of these pins is a power supply pin for the GPS. All pins on the micro-controller are GPIO pins that ...
0
votes
1answer
821 views

What is GNSS EPO orbit prediction in SIM868?

I'm little bit confused about the purpose of GNSS EPO orbit prediction functionality in SIM868 over a hot start,cold start or warm start. I'm working on a GPS tracker project and which among the ...
0
votes
1answer
259 views

Can every L1 GPS/GLONASS/BeiDou GNSS antenna receive E1 Galileo too?

I want to buy a survey grade single frequency L1 GPS/GLONASS/BeiDou/Galileo GNSS antenna (survey antennas have a ground plane built in). I found a product that specifies it is a GPS/GLONASS/BeiDou ...
0
votes
1answer
208 views

Blocking DC power to active GPS antenna

I would like to connect two GPS receivers to a single active antenna letting the DC voltage form only one receiver to reach the antenna. In this blog post the guy made his own RF part by putting a ...
5
votes
4answers
323 views

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 ...
0
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1answer
67 views

GPS and PIC16F876A

I am trying to configure a GPS receiver with PIC16F876A. In the code below i am receiving characters from UART, and checking whether received character is $. If ...
6
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3answers
9k views

GPS Antenna | When is an Active Antenna really Necessary?

Many vendors provide positioning modules that support active antennas as well as ones that don't. I am using 4 positioning modules out of which 3 of them support active antennas and the other , CC4000 ...
-3
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1answer
253 views

Trying to find documentation on UNV-SIM7100C-EVB MINI-V1.11

As the title states, I have the UNV-SIM7100C-EVB MINI-V1.11 connected to my Nucleo-F401re board and am trying to get GPS working. Can anyone help? EDIT: I'm looking for the one bought from here: ...
1
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2answers
434 views

GPS Antenna Testing

I want to test my GPS antenna. The problem is that my test setup is inside the room and not near to the window. It is not getting locked. Now as the setup has several connections, I can not take my ...
1
vote
2answers
474 views

Impedance matching: L-network or micro strips?

I'm trying to embed a u-blox neo6m gps module to an stm32 controlled board. I'm planning to connect the module to an SMA connector and use a 50ohm antenna. The datasheet of the neo6m states that the ...
5
votes
3answers
4k 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 ...
0
votes
2answers
197 views

Does GPS module need a wireless service? do I have to pay a service to get my gps module working?

Hi I'm new in the GPS world, I'm looking for a GPS module to track X amount of object the question is do I have to pay any service (cellular, data,etc) to get my gps working? I'm sorry for the dumby ...
10
votes
5answers
709 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
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2answers
107 views

Optimal sensor for measuring object velocity in an open area?

I am trying to measure vertical and horizontal speed of an object attached to a parachute. It will be launched from a low altitude and in an open area, allowing satellite GPS lock. Data treatment ...

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