Last week’s announcement by DirecTV Group Inc. that it will begin offering targeted advertising in 2011 is likely to heat up the battle between cable and satellite over advertising dollars, industry analysts said.

The El Segundo company, which is controlled by media mogul John Malone’s Liberty Media, said it was teaming up with a New York company called Invidi Technologies Corp. to provide the advertising service.

The service is considered a major technological advance for satellite providers because it will allow advertisers to offer localized TV ads targeting subscribers by a variety of geographic breakdowns such as congressional district, subdivision or even proprietary retail trading zone.

Satellite television advertisers in the past have had to buy ads across the network’s entire “national footprint” covering all of its subscribers. That put it at a disadvantage to cable providers that have long been able to locally target advertising.

The new technology “is the real Holy Grail of advertising,” said Michael Kubin, executive vice president of Invidi, which recently completed a similar deal with Dish Network, DirecTV’s major satellite competitor.

“This is huge. Frankly, once this is all deployed, things will never be the same,” Kubin said.

A spokesman for DirecTV could not be reached for comment, but in a press release, Bob Riordan, senior vice president of advertising sales, said the company “is committed to delivering the best television experience available to our subscribers and that includes relevant advertising that best fits their lifestyles and interests.”

Meanwhile, cable television operators are not sitting still. The companies have been experimenting with their own ways to better focus advertising, including slicing up viewership by various demographics such as income.

Thomas V. Eagan, a media analyst for Collins Stewart LLC in New York, said cable companies will soon feel the competition from their satellite rivals.

“It’s significant because you don’t usually associate satellite operators with local advertising,” Eagan said. “This is an effort by DirecTV to get into the advertising game.”

The number of cable television subscribers in the U.S. is expected to exceed 72 million by the end of this year, compared with about 31 million who get television by satellite. However, DirecTV has been able to steadily grow its subscriber base, which recently topped 18 million.

Dish Network, which has 13 million subscribers, has a jump on DirecTV with the new advertising technology; it is set to roll it out later this year.