Decoherence and the uncertainty principle are related concepts, but they are not exactly the same thing.
The uncertainty principle, formulated by Werner Heisenberg, is a fundamental principle in quantum mechanics that states that certain pairs of physical properties, such as position and momentum, cannot both be precisely determined simultaneously. In other words, there is a fundamental limit to the precision with which certain pairs of complementary variables can be known.
Decoherence, on the other hand, is a phenomenon that occurs in quantum systems when they interact with their surrounding environment, causing their quantum properties to become entangled with the environment. This leads to the loss of coherence, or the loss of the ability to observe quantum interference effects.
While decoherence can play a role in making certain properties of a quantum system difficult to measure, it is not the direct cause of the uncertainty principle. The uncertainty principle arises from the wave-particle duality of quantum objects, where the position and momentum of a particle are described by a wave function that exhibits inherent probabilistic behavior. The uncertainty principle is a fundamental aspect of quantum mechanics, independent of decoherence.
Decoherence can, however, have practical consequences for measuring quantum systems. When a quantum system interacts with its environment, the environment can disturb the delicate quantum state, causing it to become entangled with the environment and leading to the loss of interference effects. This makes it challenging to measure the original state of the particle precisely, as you mentioned in your question. However, even without the presence of decoherence, the uncertainty principle still holds as a fundamental limitation in our ability to simultaneously determine certain pairs of complementary properties.