Secretary of State Cyrus Vance met late yesterday with Soviet Ambassador Anatoliy F. Dobrynin to offer three proposals to resolve the final issues in dispute in the strategic arms limitation treaty (SALT) talks.

U.S. sources expressed the hope yesterday that the Soviets would find the latest U.S. ideas acceptable or nearly so, and that an agreement in principle of a new SALT pact could be reached in the near future.

After numerous near-misses in earlier negotiating rounds, however, these sources would not predict flatly that a final agreement could be reacbed soon. But they said it might be achieved as early as next week.

Three substantive issues remain in the talks, which have dragged on for seven years through three administrations. Those three are:

The definition of "new missiles" under the agreement. The two powers have already agreed to be limited to the deployment of just one "new" land-based missile system during the life of the pact, but they have not yet accepted a definition of new.

In Geneva in late December, the Soviets proposed that a missile should not be considered new if its principal characteristics were no more than 5 percent greater or 20 percent less than those of an existing missile.

In other words, under the Soviet proposal either country could deploy without limit missiles whose thrust, weight and speed were either no more than 5 percent greater or 20 percent less than those of an existing system.

The United States has insisted that the margin should be 5 percent greater or less than that of an existing system, and Vance reportedly reiterated that view yesterday. U.S. official have speculated that the 20 percent less figure suggested by the Soviets in December meant they are developing one or more new missiles that are actually smaller than existing ones they would like to deploy. The U.S. will continue to oppose this Soviet idea, sources said.

The status of cruise missiles that can carry more than one thermonuclear warhead and can aim those warheads independently at different targets.

The Soviets have proposed banning such cruise missiles. (The cruise missile is a pilotless drone that flies in the Earth's atmosphere.) Vance told Gromyko yesterday that the United States would agree to a ban, sources said.

Controls on "Unarmed Pilotless Vehicles" (UPV's). These are drones like cruise missiles, but are used by the United States to gather intelligence, not to carry thermonuclear weapons. Because of their similarity to cruise missiles, the Soviets have insisted that the SALT pact's range limits on cruise missiles should also apply to UPV's.

Vance reportedly accepted this Soviet position yesterday, too.

American sources said concessions could be made on these two latter points without affecting signficantly any American programs or intentions.