Yes Scotland has been feeding information from an “unprecedented” 25,000 canvass returns a day into its “Yesmo” data collection and management system.
Chief executive Blair Jenkins insisted he was not taking victory for granted, but said: “On everything I know, I think we’ve got a Yes vote.”
The campaign, which has more than doubled its canvassing activity in the last week, is keeping details of the number of people it has talked to secret, but claims to have achieved a higher return than ever before.
Mr Jenkins said: “We know if we work hard in the next few days, we know the votes are there for a Yes majority. We know we will win, if we work really hard.
“The information we have would tell us that there is a Yes vote there. We have to make sure we get it out, we have to make sure we get every last vote out.”
He added: “I think we will win if everyone who has told us they are voting Yes votes Yes.”
The campaign believes that interventions into the debate made this week by banks such as RBS and large companies such as John Lewis has only hardened support.
Mr Jenkins said: “We don’t detect any change in where the momentum was prior to the events of this week. We’re not registering any change whatsoever in terms of slowing down of momentum for Yes.
“We believe that project fear has become project panic.”
Yes Scotland, which said it would have more than 35,000 volunteers on Scotland’s streets this weekend, will be stepping up its activities again in the final days before the crucial vote on Thursday.
The campaign is embarking on a massive direct mail to 1.2 million pensioners in an attempt to reach the entire demographic in Scotland.
The appeal to older generations coincides with a statement by former SNP president, MP, MSP and MEP Winnie Ewing.
The 85-year-old said: “I’ve waited all my life for a meaningful vote and this is a meaningful vote for every older person.
“Make it Yes because there is so much at stake, a fairer, democratic Scotland which we all want.
“I’m old enough to appreciate having grandchildren, so I’m in a position to realise that it’s vital for them to grow up in a fair society where their aspirations are listened to and where they’re afforded the chance that they need - and that’s what I hope the young persons in this country will get in a democratic Scotland.”
An open letter has also been signed by 133 past and present Labour members calling for a Yes vote.
The letter reads: “We believe that independence will give us the greatest opportunity...to take control of the decisions affecting our economy and society.
“It will also give us a return to a real Labour Party here in Scotland. We know that a Yes vote is not a vote for nationalism but to take the important economic and political decisions that will help put right the ills in our society.”
A sell out concert with artists including Franz Ferdinand, Amy Macdonald and Mogwai is due to take place at the Usher Hall in Edinburgh tonight.