Apple on Tuesday unveiled a new iPhone 4S, the fifth update to its iconic smartphone.

There was still speculation that the company could introduce another completely redesigned iPhone, called the iPhone 5, later in Tuesday’s gathering.

At its Cupertino, Calif., headquarters, CEO Tim Cook took the stage to demonstrate the long-awaited device. It was the public appearance for the new CEO since he took the company’s reins from Steve Jobs on Aug. 24.

The announcement comes at a crucial time for Apple in the mobile space. Google’s Android operating system, which runs on over 100 mobile devices around the globe, has grown to more than double the iPhone’s share of the smartphone market, according to Gartner.

Apple is closing in on No. 2 Nokia, but the Finnish company is expected to make a big push back into the United States after it unveils its first Microsoft Windows Phone devices later this year. Meanwhile, Research In Motion is amid a refresh of its BlackBerry lineup.

App developers are still largely favoring Apple’s iOS operating system, since it also runs on the iPad and iPod Touch, in addition to the iPhone. That has given Apple the opportunity to boast that it has the most applications available for its devices. But that could change, as the iPad is also soon to face pressure. Amazon last week unveiled its new Kindle Fire tablet, which will run on the Android operating system and undercut the iPad’s lowest selling price by $300.

In its attempt to stave off growing competition, the company unveiled a new iPhone, called the iPhone 4S. The new phone will appear the same as the iPhone 4, but it will feature a new, faster processor called the A5, which is currently used in the iPad 2. It will also feature a better, 8 megapixel camera and an improved antenna.

It’s been 15 months since Apple’s iPhone 4 went on sale, making this lag between new models the longest since the iPhone debuted in 2007. Apple has typically unveiled its new iPhone at its Worldwide Developers Conference in June, but this year, Steve Jobs reserved that time to preview the company’s new software, including the iPad and iPhone’s iOS operating system, the new Mac OS X Lion operating system, and iCloud.

Despite the delays in launching a new version, demand for the iPhone 4 has remained insatiable. Apple sold a record 20 million of the devices in the second quarter, and early analysis points to another record quarter over the past three months. A recent RBC Capital survey suggested sales of the new iPhone would likely top those of the record-setting iPhone 4.

The fall is also when Apple has traditionally updated its iPod lineup, so company said it refreshed both the Nano, which will go on sale Tuesday, and the iPod Touch.

The Nano got improved navigation with finger swipes, and the price was reduced: $129 for the 8 gigabyte model and $149 for 16 GB. The Touch will come in white, and it will run the new iOS 5 software.