In ancient India, sailors primarily relied on stargazing and celestial observations to navigate. They used the positions of stars and constellations to determine their location and direction.

The astrolabe was a versatile instrument used by Indian sailors to measure the altitude of celestial bodies above the horizon. It allowed them to determine their latitude and longitude.

The monsoon winds played a crucial role in Indian navigation. They enabled trade and travel, supported fishing and pearl diving activities, and facilitated the exploration of new lands.

There is no evidence to suggest that an Indian sailor led the first circumnavigation of the globe. This achievement is attributed to Ferdinand Magellan.

The 'Periplus of the Erythraean Sea' was a valuable guide for merchants and sailors, providing detailed information on trade routes, ports, and commodities available in the Indian Ocean region.

The Chola Dynasty, particularly during the reign of Raja Raja Chola I and his son Rajendra Chola I, made significant advancements in maritime trade and exploration. They established trading networks across the Indian Ocean and beyond.

The 'Yavanajataka' was an important astronomical text that provided methods for calculating the positions of celestial bodies, which was crucial for navigation and determining latitude and longitude.

Bhāskara II, also known as Bhāskarāchārya, wrote the 'Yuktibhāṣā', which covered various aspects of mathematics, astronomy, and navigation. It included methods for calculating the positions of celestial bodies and determining the direction of travel.

The 'Keralolpathi' was a practical guide for coastal navigation, providing detailed instructions on how to navigate along the Indian coastline, including information on landmarks, tides, and currents.

Brahmagupta made significant contributions to trigonometry and navigation. He developed formulas for calculating the sine and cosine functions, which were essential for solving problems related to navigation and astronomy.

The 'Lilavati' was a comprehensive mathematical treatise that covered various topics, including arithmetic, algebra, geometry, and trigonometry. It provided methods for solving a wide range of mathematical problems, including those related to navigation.

Alauddin Riayat Shah II, the Sultan of Bengal, led a successful naval expedition to Southeast Asia in the 15th century. He established trade relations with various kingdoms in the region and demonstrated the prowess of Indian sailors.

During the Mughal Empire, Indian sailors began to adopt the compass as their primary navigational tool. The compass allowed them to determine their direction of travel more accurately, especially during long voyages.

Calcutta (now Kolkata) emerged as a major port city during the British colonial period. It became a hub for trade and maritime activities, connecting India with various parts of the world.

In the modern era, Indian sailors primarily rely on GPS (Global Positioning System) for navigation. GPS provides accurate positioning and navigation information, making it an essential tool for seafaring.