Those yet to pick themselves up a smartphone are an indecisive lot, as well as the next target market for Google and Apple, according to a report released yesterday by Nielsen.

Among likely smartphone upgraders, it is the “Late Adopters” who are most likely to say they are “not sure” which operating system they’d like in their next smartphone. According to Nielsen, fully 30 percent of late adopters are not sure which mobile OS they’re targeting when they make the leap to a bigger, better device.

However, among those who say they are usually the first to embrace new technologies, a segment that Nielsen calls “Innovators” (one step above the “Early Adopter”), Android leads as the “Next Desired Operating System.” Fully 40 percent of Innovators chose Android compared to 32 percent who said they’ve got their sights set on an iOS device.

Overall, among those who say they are likely to get a new smartphone in the next year, approximately one-third said they want their next smartphone to be an iPhone and one-third say they want an Android device.

According to Nielsen data from July 2011, 40 percent of mobile consumers over 18 in the U.S. now have smartphones. Of those, Android is the most popular operating system, with 40 percent of mobile consumers reporting they have a smartphone with an Android OS. Apple’s iOS is in second place, with 28 percent.