Antenna

In GNSS positioning, the antenna often decides the result before algorithms do.

The same module and firmware can behave very differently after changing enclosure, antenna position, or placing the device inside a metal cabinet.

GNSS receives extremely weak satellite signals. If the antenna does not receive a clean signal, the receiver and software cannot easily recover.

The Antenna Needs Sky View

A GNSS antenna should face the sky. Patch, ceramic, and FPC antennas have directionality and installation requirements.

Many devices with GPS fail indoors. Logs may show few satellites, no fix, jumping position, or a very long time to first fix.

This does not always mean the module is broken. GNSS signals are weak by nature.

GNSS positioning receives signals from multiple satellites and estimates distance and time error. By the time satellite signals reach the ground, they are already weak. Indoors, walls, floors, metal enclosures, the human body, coated glass, and installation direction attenuate them further.

Many field issues look like protocol failures: intermittent offline events, poor coverage at the edge, phones working while sensors do not, or range dropping after an enclosure change. Before debugging the state machine, ask a lower-level question: does the wireless link have enough energy margin?

Antenna, transmit power, and link budget decide how much usable signal remains after the signal leaves the transmitter and passes through space, walls, people, enclosure material, and antenna direction.