Why in News:
- Signatures of Iridium satellite phones, used by the US-led allied forces in Afghanistan, and Wi-Fi-enabled thermal imagery devices that help a terrorist to escape security cordons especially during night have been found in the militancy-hit Kashmir valley.
- In the aftermath of the 2008 Mumbai terror attacks, the Directorate General of Shipping (DGS) first restricted the use of Iridium and Thuraya satellite phones and infrastructure, and in 2012 completely banned them the under the provisions of the Indian Telegraph Act.
- A satellite phone is a phone that can communicate with satellites in orbit. They can connect to voice and short message services, as well as low-bandwidth Internet access, much like terrestrial mobile phones.
- Because satellite phones are directly connected to satellites throughout the world and do not rely on terrestrial mobile cellular networks, they can connect from anywhere.
- A satellite phone is designed to work outside, mostly when a mobile phone is not functional owing to a lack of a network, which is more typically in very remote locations and, on occasion, in harsh weather. Satellite phones are very beneficial in the world’s most remote locations, such as mountains, woods, poles, deserts, and the middle of the ocean.
Thermal imagery devices
- Thermal imaging cameras are handheld electronic devices with an integrated visual display, designed for detecting heat energy.
- The key component of a thermal camera is a heat sensor attached to a special type of lens, which is then adapted to work alongside standard image-capture technologies
- Visible light forms only a small part of the electromagnetic spectrum, and the only part we can actually see.
- When pointed at an object or area, the sensor on a thermal detection camera allows the user to view the otherwise invisible infrared spectrum, which exists at wavelengths between visible light and microwaves. This is often rendered as a colour map in modern IR cameras.
- On a colour thermographic display, warmer components or regions will show up as reds, oranges and yellows, while cooler parts will typically be shown as purples and blues (green usually indicates areas that are roughly at room temperature).
- Because they measure infrared radiation, and not visible light, thermal cameras are also useful for identifying heat sources in very dark or otherwise obscured environments.