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Does GPS transmit different data into LNAV and CNAV messages?

Global Positioning Systems *Development of communication systems *

Different navigation message protocols are used for different navigation signal type. This is true even for a single system like NAVSTAR GPS. For example, L1C/A signals have a LNAV protocol, while L2C and L5 signals utilize a CNAV protocol. The newest L1C signal will use CNAV-2. 

The protocol defines a data distribution into frames, subframes, the subframes structure, transmission intervals, data resolution and so on. 

A navigation receiver use the navigation message data flow for several purposes:

1. The data flow allows to resolve a code ambiguity and set the signal time.

2. Ephemeris and clock values are used for the satellite position calculation, pseudorange corrections and coordinates computation.

3. The received data flow and navigation message data can be used for navigation symbols prediction. As result, we can use the wipe-off technique, expand discriminators and significantly increase tracking sensitivity:

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Total votes 3: ↑3 and ↓0 +3
Views 899
Comments 0

PHDays 11: bootkit infection, sanitizers for the Linux kernel, the new face of OSINT, and phishing on official websites

Positive Technologies corporate blog Configuring Linux *Information Security *Programming *Conferences

Positive Hack Days 11 will begin in a matter of weeks. This international forum on practical security will be held on May 18–19 in Moscow.

As per tradition, PHDays will have three big tracks dedicated to countering attacks (defensive), protection through attack (offensive), and the impact of cybersecurity on business. It is our pleasure to present the first talks.

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Total votes 1: ↑0 and ↓1 -1
Views 704
Comments 0

Audio API Quick Start Guide: Playing and Recording Sound on Linux, Windows, FreeBSD and macOS

Programming *C *Development for Linux *Development for Windows *Sound
Tutorial

Hearing is one of the few basic senses that we humans have along with the other our abilities to see, smell, taste and touch. If we couldn't hear, the world as we know it would be less interesting and colorful to us. It would be a total silence - a scary thing, even to imagine. And speaking makes our life so much fun, because what else can be better than talking to our friends and family? Also, we're able to listen to our favorite music wherever we are, thanks to computers and headphones. With the help of tiny microphones integrated into our phones and laptops we are now able to talk to the people around the world from any place with an Internet connection. But computer hardware alone isn't enough - it is computer software that really defines the way how and when the hardware should operate. Operating Systems provide the means for that to the apps that want to use computer's audio capabilities. In real use-cases audio data usually goes the long way from one end to another, being transformed and (un)compressed on-the-fly, attenuated, filtered, and so on. But in the end it all comes down to just 2 basic processes: playing the sound or recording it.

Today we're going to discuss how to make use of the API that popular OS provide: this is an essential knowledge if you want to create an app yourself which works with audio I/O. But there's just one problem standing on our way: there is no single API that all OS support. In fact, there are completely different API, different approaches, slightly different logic. We could just use some library which solves all those problems for us, but in that case we won't understand what's really going on under the hood - what's the point? But humans are built the way that we sometimes want to dig a little bit deeper, to learn a little bit more than what just lies on the surface. That's why we're going to learn the API that OS provide by default: ALSA (Linux), PulseAudio (Linux), WASAPI (Windows), OSS (FreeBSD), CoreAudio (macOS).

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Rating 0
Views 1.7K
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The Significance of In-app Messaging Applications in your Digital Business

Instant Messaging *Development of mobile applications *API *Software Video conferencing

In-app messages are targeted notifications sent to customers/ users while they are active on the website or mobile application. They are a very effective way to engage customers as they are already within the application looking for specific information. In-app chat applications help connect better with the users and improve user retention as they are timely and targeted. 

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Rating 0
Views 572
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Android for electronics design engineers

CAD/CAM *Circuit design *Manufacture and development of electronics *DIY Electronics for beginners

There is a list of well-known electronics design tools for Android which can be found in every review for the last 10 years: “Electrodoc”, “Every Circuit”, “Droid Tesla”, “Electronics Toolbox”, “RF & Microwave Toolbox” and so on. Also, there is a lot of trash on the market that turns finding a good tool into a quest.

This short review is about an unknown but cool tool “Circuit Calculator” working on Android devices and intended for professional electronics designers.

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Total votes 4: ↑4 and ↓0 +4
Views 1.1K
Comments 0

Simple rest based kogito microservice with several embedded pmml models

Java *Business Models *Kubernetes *
Tutorial

In previous post I've described an example of kogito-based microservice on quarkus in native mode, containing one embedded pmml model with decision tree. While it can be successfully used for prototyping purposes, in the real life microservice might contain several prediction models. From the first view I've got an impression, that inclusion of several models should be a trivial extension of the prototype with one model. We were completely wrong in our assumption, that's the reason, why I've decided to write this post. Another reason, is absence of guides, in which 2 (or more models) are put inside DMN diagrams in kogito framework.

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Total votes 1: ↑1 and ↓0 +1
Views 951
Comments 0

Our new public speech synthesis in super-high quality, 10x faster and more stable

Machine learning *Natural Language Processing *Voice user interfaces *

hero_image


In our last article we made a bunch of promises about our speech synthesis.


After a lot of hard work we finally have delivered upon these promises:


  • Model size reduced 2x;
  • New models are 10x faster;
  • We added flags to control stress;
  • Now the models can make proper pauses;
  • High quality voice added (and unlimited "random" voices);
  • All speakers squeezed into the same model;
  • Input length limitations lifted, now models can work with paragraphs of text;
  • Pauses, speed and pitch can be controlled via SSML;
  • Sampling rates of 8, 24 or 48 kHz are supported;
  • Models are much more stable — they do not omit words anymore;

This is a truly break-through achievement for us and we are not planning to stop anytime soon. We will be adding as many languages as possible shortly (the CIS languages, English, European languages, Hindic languages). Also we are still planning to make our models additional 2-5x faster.


We are also planning to add phonemes and a new model for stress, as well as to reduce the minimum amount of audio required to train a high-quality voice to 5 — 15 minutes.


As usual you can try our model in our repo or in colab.

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Total votes 13: ↑13 and ↓0 +13
Views 1.8K
Comments 0

Django admin dynamic Inline positioning

Python *Django *
Translation
Tutorial

Recently I've received an interesting request from a client about one of our Django projects.
He asked if it would be possible to show an inline component above other fields in the Django admin panel.

At the beginning I thought, that there shouldn't be any issue with that.
Though there was no easy solution other then installing another battery to the project. My gut feeling told me, there were another way around that problem.

Read more about ModelAdmin with Inlines
Total votes 2: ↑2 and ↓0 +2
Views 2.4K
Comments 0

Working with digital infrared passive motion sensor PYD 1588

Programming microcontrollers *

In this article, there is the work with the PYD 1588 digital Infrared passive motion sensor introduced. The PYD 1588 is a serial opposed format, two element detector based on pyroceramic produced by the Excelitas Technologies. This sensor represents a low-power (3.0 uA with 1.8 V source voltage as in the documentation said) passive component with two sensible elements, which measure the thermal infrared radiation stream.

The signal is converted to a digital value using Sigma-Delta and DSP techniques. A configurable motion detection unit is implemented, which can generate an interrupt recognized by the external microcontroller (MCU) in case motion is detected. The motion detection unit contributes to significant device energy efficiency increasing via putting the MCU to a low-power sleep mode with no periodic raw data request and its analyzing necessity.

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Total votes 3: ↑3 and ↓0 +3
Views 946
Comments 1

Comparison between SwiftUI vs UIKit — Choosing the right framework

Self Promo

There has been a lot of debate going on among iOS developers with regards to the comparison between SwiftUI and UIKit. Have you been planning to develop a chat app for iOS and are confused as to which framework you should opt for?

Fret not! We have got your back. In this article, we shall discuss all the relevant aspects revolving around these two and compare them in detail. Stay with us and read on! 

As iOS developers, you must be knowing about both the UIKit and Swift UI frameworks. However, we would like to provide you with a quick overview to refresh your understanding. Let's take them up one by one

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Rating 0
Views 4.8K
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The journey of scaling up a production Elasticsearch cluster

High performance *NoSQL *Database Administration *Amazon Web Services *Distributed systems *

In this article, I will tell you about a-few-years journey of scaling the Elasticsearch cluster in production environment, which is one of the vital elements of the iPrice technology stack. 
I will describe challenges we encountered and how we approached them.

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Total votes 1: ↑1 and ↓0 +1
Views 1K
Comments 0

Electron + web camera (cpp-ffmpeg)

C++ *Development for MacOS *ReactJS *
Recovery mode
Sandbox

An example of using Electron + React JS and a native ffmpeg addon to access a webcamera

This guide may be helpful to someone who is trying to find a way
to work with Electron if they need to use a c++ library or code

I was looking for a more realistic example than a simple 'hello world' and i didn't succeed

Here are the links in advance:

- electron - https://github.com/khomin/electron_camera_ffmpeg

- addon - https://github.com/khomin/electron_ffmpeg_addon_camera

So let me share my experience...

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Total votes 3: ↑3 and ↓0 +3
Views 1.1K
Comments 0

Queries in PostgreSQL. Sequential Scan

Postgres Professional corporate blog PostgreSQL *SQL *
Translation

Queries in PostgreSQL. Sequential scan


In previous articles we discussed how the system plans a query execution and how it collects statistics to select the best plan. The following articles, starting with this one, will focus on what a plan actually is, what it consists of, and how it is executed.


In this article, I will demonstrate how the planner calculates execution costs. I will also discuss access methods and how they affect these costs, and use the sequential scan method as an illustration. Lastly, I will talk about parallel execution in PostgreSQL, how it works, and when to use it.


I will use several seemingly complicated math formulas later in the article. You don't have to memorize any of them to get to the bottom of how the planner works; they are merely there to show where I get my numbers from.

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Total votes 3: ↑3 and ↓0 +3
Views 1.2K
Comments 0