Uber's autonomous vehicle unit has raised $1 billion from a consortium of investors including Soft Bank Group, giving the company a much-needed funding boost for its pricey self-driving ambitions on the eve of its public stock offering.

Uber said that the investment values its Advanced Technologies Group, which works to develop autonomous driving technology, at $7.25 billion.

Soft Bank will invest $333 million from its $100 billion Vision Fund, while Toyota and automotive parts supplier Denso Corp will invest a combined $667 million.

Toyota will also contribute up to an additional $300 million over the next three years to help cover the costs of building commercial self-driving vehicles.

Uber CEO Dara Khosrowshahi said that the funding "will help maintain Uber's position at the forefront of" a transforming transportation industry.

The funding allows Uber to transfer some of the substantial cost of developing self-driving cars onto outside investors. That is likely to appease some of Wall Street's concerns over Uber's spending on the autonomous unit, which has topped $1.07 billion since the program started in 2016.