English हिन्दी
Connect with us

Latest Science News

NavIC frequency too close to WiFi, may cause interference: Study

Published

on

NavIC frequency too close to WiFi, may cause interference: Study

~By Dinesh C Sharma

NavIC, India’s very own navigation satellite system, is projected to provide positioning and navigation services on the lines of US-owned Global Positioning System (GPS). However, a new study has warned that signals from NavIC satellites may interfere with WiFi signals in receivers.

The Indian navigation and positioning system consists of a constellation of seven satellites launched by the Indian Space Research Organisation (ISRO) between 2013 and 2018. The technology is likely to be available on smartphones and car navigation systems in future.

The NavIC satellites send signals in frequency bands of L5 (1176.45 MHz) and S-band (2492.08 MHz).  S-band is utilized by NavIC for navigation systems, but the same band is also shared by other communication systems like Long-Term Evolution (LTE), Bluetooth and Wireless Fidelity (Wi-Fi).

The study says that NavIC signals get affected by  out of band interference due to Wi-Fi signal as the two are located closely. It found that “NavIC reception on S-band frequency is severely affected by Wi-Fi transmission.”

“These interfering signals present a threat to the NavIC receiver performance. To equip both the facilities (WiFi and NavIC) in future cell phones, it will be a challenge to mitigate such kind of radio frequency interference,” says the study published in journal Current Science. The study was done by Dr Shweta N Shah of Electronics Engineering Department at Sardar Vallabhbhai National Institute of Technology, Surat, and Ph D scholar Darshna D Jagiwala. ISRO’s Ahmedabad-based Space Applications Centre (SAC) provided necessary equipment for the study.

Explaining the findings, Dr Shah told India Science Wire that “NavIC has S band signals and there are much stronger terrestrial S band signals that can pose problem for S band and dual frequency Standard Positioning Service (SPS) receivers of NavIC if not addressed properly.”

Currently, she said “Wi-Fi receivers are present in every cell phone. That’s why it was necessary to study Wi-Fi interference to verify the performance of NavIC signal reception in cellphones. This kind of interfering signal represents a threat to the performance of the NavIC receivers.”

In the experimental set up having both types of receivers, it was found that a part of the S-band of NavIC system overlaps the unlicensed band which is shared by other communication technologies like Bluetooth, Wi-Fi and Industrial Scientific Medical (ISM) bands. When the frequency channel of Wi-Fi was superimposed with the frequency of the S-band signal of the NavIC receiver, interference was observed in S-band signal of NavIC receiver due to the extremely low power level of the signal at the user’s receiver.

aaaa

Wireless experts feel radio frequency interference between NavIC and other bands may pose regulatory challenges, besides quality of services. In India, Wi-Fi signals are exempted from licensing in the frequency band 2400 – 2483.5 MHz. This means the usable part of any Wi-Fi system or channel India must be contained within 2483.5 MHz.

“Residual or unintended signals normally go beyond this limit due to the basic characteristic of digital emissions. The NavIC signal is centered at 2492.08 MHz with a bandwidth of ± 8.25 MHz. This means that the lower part of NavIC signal can get interference from residual / unintended signals of Wi-Fi systems. Also, the upper part of the NavIC signal goes beyond 2500 MHz and since the frequency band above 2500 MHz is used for other purposes, NavIC receivers can pick up signals (and receive interference) from such other systems operating above 2500 MHz,” explained Pawan Kumar Garg, former Wireless Advisor, Government of India, while speaking to India Science Wire.

“To reduce interference from Wi-Fi (below 2483.5 MHz) as well as systems operating above 2500 MHz, it is desirable that the NavIC receivers should use reduced bandwidth of ± 7.5 MHz, if possible, and with sharp cut off filters on both ends,” Garg added. (India Science Wire)

Latest Science News

Partial solar eclipse 2025 today: Timings, livestreams, double sunrise effect and safety tips

The first solar eclipse of 2025, occurring today, will not be visible from India but can be watched online via livestreams by NASA and other observatories.

Published

on

Partial solar eclipse forming crescent Sun in sky

A partial solar eclipse, the first of the year 2025, is set to unfold today, March 29. While this celestial phenomenon will be observable from several parts of the world, it will not be visible from any region in India. The eclipse is expected to start around 2:20:43 PM IST and continue until 6:13:45 PM IST, with visibility dependent on geographic location.

What is a partial solar eclipse?

Unlike a total eclipse where the Moon entirely blocks the Sun, a partial solar eclipse leaves part of the Sun exposed. As the Moon partially covers the Sun, it creates a striking crescent-like shape in the sky. Today’s eclipse is also expected to produce a rare “double sunrise” effect — where the Sun appears to rise, dim briefly, and rise again — typically visible in areas where the eclipse coincides with sunrise.

A global event, but not for Indian skies

According to space data agencies, about 100 crore (1 billion) people will be in locations where they can witness this partial eclipse. However, only around 44,800 people will see at least 90% coverage of the Sun — marking a very limited population for the highest visibility range.

Watch safely — never directly

Experts strongly advise against looking at the Sun directly during any solar eclipse. Viewers should only use certified solar viewing glasses, eclipse glasses, or handheld solar viewers. Watching through regular cameras, binoculars, or telescopes without proper solar filters can lead to severe eye damage.

Livestreaming options for virtual viewing

For those in India and elsewhere who cannot witness the eclipse directly, several global platforms like NASA and SLOOH Observatory are offering live streaming on their websites and social media channels. Indian space authorities like ISRO may also stream the event live. Viewers can access real-time visuals and expert commentary from the comfort of their homes.

The eclipse pairing rule

Astronomers remind us that eclipses always occur in pairs. This solar eclipse follows a total lunar eclipse that occurred just two weeks ago. Another pair of solar and lunar eclipses is expected to occur in September 2025, in line with the seasonal pattern of eclipses occurring roughly six months apart.

Continue Reading

Latest Science News

US President Trump says he will pay out of his pocket to Sunita Williams, Butch Wilmore for overtime stay in space

“Nobody told me about this. If it comes to it, I’ll pay it from my own pocket, alright? I’ll sort it for them,” Trump declared, visibly taken aback. “Is that it? That’s peanuts for what they’ve been through,” he added, marvelling at the modest sum given their ordeal.

Published

on

US President Donald Trump has expressed surprise upon learning that NASA astronauts Sunita Williams and Butch Wilmore, who endured an extended nine-month stint aboard the International Space Station (ISS), hadn’t received overtime pay.

Addressing reporters at a White House briefing, Trump even floated the idea of covering the costs himself, after the reporter highlighted that the duo were owed $1,430—$5 daily for 286 days.

“Nobody told me about this. If it comes to it, I’ll pay it from my own pocket, alright? I’ll sort it for them,” Trump declared, visibly taken aback. “Is that it? That’s peanuts for what they’ve been through,” he added, marvelling at the modest sum given their ordeal.

The astronauts, including Williams and Wilmore, alongside Nick Hague and Russian cosmonaut Aleksandr Gorbunov, returned to Earth on Wednesday via SpaceX’s Dragon spacecraft, splashing down off Tallahassee, Florida.

Trump showered praise on SpaceX chief Elon Musk for the rescue. “Thank heavens for Elon. Without him, who knows how long they’d have been stuck up there?” he remarked, crediting Musk’s ingenuity for their safe return.

For Williams and Wilmore, seasoned test pilots for Boeing’s Starliner capsule, what began as an eight-day mission ballooned into over nine months due to technical snags—helium leaks and thruster glitches—that rendered their craft unfit for the journey back.

The Starliner returned empty in September 2024, leaving them reliant on SpaceX. Trump underscored the physical toll of prolonged space stays. “After nine or ten months, the body starts breaking down—bones, blood, the works. It gets grim beyond 14 months. Without Elon, they’d be in a fix,” he said.

In a tangent, Trump drew parallels between Musk’s challenges and his own, claiming Tesla faced vandalism akin to the 6 January 2021 riots. “Elon’s had his share of trouble too,” he noted, blending admiration with a touch of defiance.

Continue Reading

Latest world news

Sunita Williams returns home after 286 days at space, greeted with smiles and applause

Astronaut Sunita Williams returned home after an unplanned 286-day mission in space, originally intended to last only eight days.

Published

on

Sunita Williams waving after returning from space

NASA astronaut Sunita Williams and her crewmate Butch Wilmore have successfully returned to Earth after spending an unexpected 286 days in space. Originally meant to be an eight-day mission, the duo faced prolonged delays due to technical issues with the Boeing Starliner spacecraft, which left them stranded aboard the International Space Station (ISS).

Williams and Wilmore finally made their journey back aboard SpaceX’s Dragon spacecraft, which splashed down in the ocean near Florida. The mission, which initially launched on June 5 last year, concluded with a safe landing early this morning.

Splashdown near Florida

After spending 17 hours in transit back to Earth, the capsule deployed its parachute, ensuring a controlled descent before making a water landing. NASA teams were on standby to retrieve the astronauts, assisting them onto mobility aids as they adapted to Earth’s gravity.

Williams was seen waving and flashing thumbs-up signs as she emerged from the capsule, signaling a positive return despite the physical challenges posed by prolonged space travel.

SpaceX ensures safe return

The return of the astronauts was made possible through SpaceX’s Crew-9 mission. The Dragon capsule, which was launched atop a Falcon 9 rocket, was sent to replace Crew-9 at the ISS. The spacecraft undocked at 10:35 am (IST), with NASA sharing visuals of the departure.

From an eight-day mission to nine months in space

Williams and Wilmore initially traveled to the ISS on what was to be the first crewed flight of Boeing’s Starliner spacecraft. However, the Starliner developed propulsion issues and was deemed unfit for the return journey. NASA reassigned them to SpaceX’s Crew-9, and in September, a Dragon capsule was sent with a two-member crew to ensure their safe return.

After multiple delays, a relief team finally arrived on Sunday, paving the way for their journey home.

Challenges faced by returning astronauts

A prolonged stay in space presents multiple health challenges. Astronauts experience muscle and bone density loss due to the lack of gravity, which can lead to long-term physical impairments. NASA estimates that for every month in space, astronauts’ weight-bearing bones lose approximately one percent of their density.

Radiation exposure is another concern, as the Earth’s atmosphere provides protection that is unavailable in space. Vision impairment and weakened muscles are also common issues faced by astronauts after extended space travel.

PM Modi acknowledges Sunita Williams’ achievements

Ahead of her return, Indian Prime Minister Narendra Modi sent a letter to Sunita Williams, praising her resilience and contribution to space exploration. The letter, dated March 1 and shared publicly by Union Minister Jitendra Singh, expressed India’s pride in Williams’ achievements.

PM Modi mentioned that he had discussed Williams’ mission with both former US President Donald Trump and his predecessor, Joe Biden, during his visits to the United States. “1.4 billion Indians have always taken great pride in your achievements. Recent developments have yet again showcased your inspirational fortitude and perseverance,” the letter read.

Williams’ return marks the end of an eventful mission filled with challenges and triumphs, further reinforcing her legacy as a seasoned space traveler.

Continue Reading

Trending

© Copyright 2022 APNLIVE.com