A new polling organisation gathering data on Scotland’s evolving views on independence has been launched by the Scottish National party’s former Westminster leader Angus Robertson, as the party leader and first minister, Nicola Sturgeon, prepares to set out her thinking on a second referendum.

Robertson, a respected figure across the party who lost his seat in the 2017 general election, is heading up Progress Scotland alongside Mark Diffley, previously director of Ipsos Mori Scotland, who served as the lead pollster for the UK government in the run-up to the 2014 independence referendum.

The pair plan to fund their work through donations and public subscriptions, with polling analysis and other information then released to subscribers.

The initiative was warmly welcomed on Sunday by pro-supporters of independence, including Sturgeon, who described it as “brilliant”.

After Theresa May’s historic defeat in the Commons last month, the first minister said she would reveal her timetable for a second independence referendum “within a matter of weeks”.

Sturgeon insisted last week the attempted rape and sexual assault charges against her predecessor Alex Salmond would have no impact on the plans, stating that the case for independence was “bigger than any one man”.

Other senior figures greeted the launch more cautiously. The MP and prominent people’s vote campaigner Joanna Cherry, who has previously raised concerns about a lack of referendum planning, stressed that work was needed on policies and vision for an independent Scotland. She has suggested engagement with voters across the spectrum of Scottish political opinion through a constitutional convention and citizens’ assembly.

The initiative comes at at time when the SNP is desperately in need of a fillip. A number of MSPs have described their local party activists as “shell-shocked” after Salmond appeared in court two weeks ago charged with multiple counts of sexual assault and two of attempted rape.

Robertson said neither Sturgeon’s announcement nor Salmond’s arrest had any bearing on the timing of the launch.

He told the Guardian: “There’s been a gap for a while in our understanding of where people are at, and how people’s views are evolving. We also need an understanding of what are the most powerful arguments for independence.”

Launch material for the project includes testimonials from a number of figures who have changed their views on independence since 2014. These include Murray Foote, a former editor on the Daily Record who facilitated the infamous “vow” with David Cameron, and the former UK judge on the European court of justice Sir David Edward. The “vow” was a pledge made by the three English-based party leaders that, in return for voting against independence, further powers would be devolved to Scotland.

A gradualist on independence, who was campaign director for the SNP’s three most successful election campaigns, Robertson said there was not as much research infrastructure in place within the SNP as observers assumed.

“Brexit is hugely dynamic,” he said. “People don’t know what the status quo is. Polling would appear to show a larger majority now want to stay within the EU than at the time of the EU referendum, but how does that operate on independence?”

At the end of January, the Scottish Independence Convention, a non-aligned grouping first established in 2005 but now reconvened to drive support for a second referendum, announced it had raised more than £100,000 through crowdfunding and would be interviewing for a full-time staff member to coordinate activity.

“These are all complementary projects,” said Robertson. “There is currently an appetite for things to be prepared properly and researched.”