Scotland’s constitution secretary insisted on Sunday the SNP would continue to push for a vote based on a section 30 order.
A section 30 order refers to the section of the Scotland Act that allows Holyrood to pass laws normally reserved to Westminster.
Speaking on BBC Scotland's The Sunday Show, Mr Robertson said: "We will continue to press for the gold standard, which the 2014 referendum showed itself to be.
"With a section 30, a legal referendum could go ahead and be recognised by the UK Government and other countries.
"Given we have precedent, and it worked and wasn't complicated, and with mutual respect, it was something we could all agree on.
"If it was possible then, there is no reason why it is not possible now."
Following reports First Minister Nicola Sturgeon plans to reword the question to avoid a section 30 order, Mr Robertson declined to comment on any alternative plans.
Scottish Labour leader Anas Sarwar dismissed the idea of a second referendum.
He said: "The next electoral contest is not a referendum. It is going to be a general election and that is going to be a campaign to put out Boris Johnson.
"The anger we feel sitting in Glasgow, is felt in Edinburgh, it is felt in Cardiff, Birmingham, Manchester and London. Let's unite across this country, put out Boris Johnson.
"I honestly believe the majority of people still don't want independence."
A UK Government spokesman said: "Now is not the time to be talking about another referendum.
"People across Scotland rightly want and expect to see both of their governments working together with a relentless focus on the issues that matter to them, their families and communities.
"That means tackling the cost of living, protecting our long-term energy security, leading the international response against Russia's invasion of Ukraine and growing our economy, so that everyone has access to the opportunities, skills and jobs for the future."