A GPS receiver (Global Positioning System Receiver) is an electronic device used to receive satellite signals from the Global Positioning System (GPS). It can accurately determine its own position (usually with an error of meters to centimeters) by analyzing the time, location and other information in the satellite signals, and supports navigation, positioning, timing and other functions. The following is a detailed introduction from multiple dimensions:

Ⅰ. Core working principle

The core of the GPS receiver is based on the principle of triangulation positioning. By receiving signals transmitted by multiple GPS satellites (at least 4), it calculates the distance difference between itself and each satellite, and finally solves the three-dimensional coordinates (longitude, latitude, altitude) and time information. The specific steps include:

1. Signal capture: The receiver searches and locks the signal of the visible satellite (L-band microwave, frequency of about 1.575GHz) through the built-in antenna.

2. Pseudo-range measurement: Calculate the time difference from the satellite signal from transmission to reception (multiplied by the speed of light) to obtain the "pseudo-range" from the receiver to the satellite (because the receiver clock error will introduce deviation).

3. Positioning solution: Using pseudo-range data from at least four satellites, combined with satellite orbit parameters (ephemeris), mathematical models (such as the least squares method) are used to eliminate the receiver clock error and solve for accurate three-dimensional position and time.

Ⅱ.Key classification

GPS receivers can be classified by purpose, technical characteristics, performance and other dimensions:

1. Classification by purpose

Consumer-grade receivers: commonly found in mobile phones, car navigation systems, sports watches, etc., focusing on portability and basic positioning (accuracy is usually 210 meters), supporting navigation, track recording and other functions.
Professional-grade receivers: used in surveying and mapping, geological exploration, precision agriculture and other fields, requiring high accuracy (centimeter to millimeter level), usually equipped with high-sensitivity antennas, differential technology (RTK/PPK) and industrial-grade protection.
Timing receivers: mainly used in communication base stations, power grids, financial transactions and other scenarios that require high-precision time synchronization (nanosecond error).

2. Classification by technical characteristics

Single-frequency receivers: only receive L1 band signals (1575.42MHz), low cost but easily affected by ionospheric delay, average accuracy (210 meters), suitable for ordinary navigation.
Dual-frequency receiver: Receives L1/L2 (or L1/L5) band signals at the same time, eliminates ionospheric errors through dual-frequency, and significantly improves accuracy (static measurement can reach millimeter level, dynamic centimeter level), commonly used in surveying and autonomous driving.
Differential GPS (DGPS) receiver: By receiving differential correction signals (RTK real-time dynamic/PPK post-processing) from ground base stations, it further eliminates satellite orbit errors, atmospheric delays, etc., and improves positioning accuracy.

3. Classification by integration method

Independent receiver: A single device (such as a handheld GPS device, surveying and mapping instrument) with focused functions.
Modular receiver: Integrated into other devices (such as mobile phones, car navigation, drones) in the form of chips or modules, with small size and low power consumption.

Ⅲ.Core performance parameters

When choosing a GPS receiver, pay attention to the following key parameters:

Positioning accuracy: static accuracy (in a fixed state) and dynamic accuracy (in motion), which is affected by the number of satellites, signal quality, and differential technology.

Sensitivity: The ability to receive weak signals (in dBm). High sensitivity can maintain positioning in obstructed environments (such as urban canyons and under the shade of trees).

Number of channels: The number of satellites that can be tracked simultaneously (modern receivers usually have ≥50 channels). The more channels, the stronger the ability to capture and track satellites.

Update rate: The frequency of position output (Hz). High update rate (such as above 10Hz) is suitable for high-speed mobile scenarios (such as drones and racing cars).

Anti-interference ability: Supports technologies such as anti-multipath effect (reflected signal interference) and anti-electromagnetic interference to improve reliability in complex environments.

Power consumption: affects battery life. Low power consumption design (such as μA current) is suitable for wearable devices and trackers.

IV. Typical application scenarios

Navigation and travel: in-vehicle navigation, mobile phone maps, and drone track planning.
Surveying and geographic information: land surveying, engineering stakeout, terrain modeling (relying on high-precision receivers + RTK technology).
Precision agriculture: self-driving tractors, variable fertilization (controlling the path of agricultural machinery through centimeter-level positioning).
Logistics and tracking: truck/express tracking, cold chain monitoring (real-time location and status feedback).
Emergency rescue: field search and rescue, disaster monitoring (sending distress signals through Beidou short messages + GPS positioning).
Scientific research: earthquake monitoring (inverting crustal movement through receiver displacement data), wildlife tracking.

V. Development trend

Multi-system integration: support multi-mode reception such as GPS (US), Beidou (China), Galileo (EU), GLONASS (Russia), etc., to improve the number of satellite visible and positioning reliability (especially in complex environments).
Popularization of high precision: the cost of dual-frequency receivers has decreased, and RTK technology has gradually become civilian (such as mobile phones supporting centimeter-level positioning).
Low power consumption and miniaturization: chip process improvements (such as SiP packaging) promote the integration of high-precision positioning in wearable devices and IoT terminals.
Enhanced anti-interference: Adaptive zeroing antenna, AI algorithm filtering and other technologies to cope with complex scenarios such as cities and electromagnetic interference.
Fusion positioning: Complementary with inertial navigation (IMU), WiFi, Bluetooth, visual SLAM and other technologies to achieve seamless indoor and outdoor positioning.

Summary

GPS receiver is the core terminal of satellite navigation technology, and its performance directly affects the accuracy and reliability of positioning. With the development of technology, from consumer level to professional level, the functions of receivers are constantly expanding, and the application scenarios cover all aspects of production and life. In the future, it will be integrated with more emerging technologies to promote the evolution of "location services" to a smarter and more ubiquitous direction.