Does GPS transmit different data into LNAV and CNAV messages?

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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Does GPS transmit different data into LNAV and CNAV messages?
Source: habrahabr

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

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

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

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

The Significance of In-app Messaging Applications in your Digital Business

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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The Significance of In-app Messaging Applications in your Digital Business
Source: geektimes

Android for electronics design engineers

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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Android for electronics design engineers
Source: geektimes

Simple rest based kogito microservice with several embedded pmml models

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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Simple rest based kogito microservice with several embedded pmml models
Source: habrahabr