radar

In-cabin monitoring systems (ICMS) are reshaping the concept of passenger safety in cars. Various applications such as left-behind child detection, driver well-being, or occupancy sensing increase road safety and the protection in vehicles. Radar, in particular, is a promising technology to address these applications due to its ability to detect micro-motions and vital signs. With…

Wireless communication has been around since 18th century. James Clerk Maxwell first proposed that the electromagnetic waves can be generated and they can travel through free space. Heinrich Rudolf Hertz conducted the experiments in which he demonstrated the generation, transmission and reception of electromagnetic waves which became the basis of Radio Frequency communication. The wireless communication was first introduced as wireless telegraphy in 1890 which soon became popular by the name radio telegraphy. It all started when Guglielmo Marconi developed first wireless telegraph system in 1896. The technology progressed in early 1900s with the introduction of commercial radiotelephony and  by 1960s first communication satellites were in space.

When we start reading about radar, we come across various terms which are explained differently. There are various kinds of Radar classified in different ways. This article explains the various radar types in a lucid manner. A Primary Radar transmits high-frequency signals toward the targets. The transmitted pulses are reflected by the target and then received by the same radar. The reflected energy or the echoes are further processed to extract target information. Secondary radar units work with active answer signals. In addition to primary radar, this type of radar uses a transponder on the airborne target/object. The secondary radar unit transmits and also receives high-frequency impulses, the so called interrogation. This isn’t simply reflected, but received by the target by means of a transponder which receives and processes. After this the target answers at another frequency.

If you have sometimes experienced the reflection of a sound due to the presence of a sound reflecting object like a canyon/ cave, etc. you have in a way experienced how radar functions. When you shout near towards a valley or a mountain, the reflection of a sound, i.e., the echo comes back. The time an echo requires to come back can be used to estimate the distance of the reflecting object, provided the speed of sound in air is known. Radar functions in a similar manner to find out the location of the reflection object using RF waves. Radar is an acronym for RAdio Detecting And Ranging. The name itself suggests that the radars are used to detect the presence of object and determine its range, i.e., distance and bearing, using radio frequency waves.