GPS antenna is a key component for receiving satellite signals of the Global Positioning System (GPS). Its core function is to convert the radio waves (L band, mainly 1575.42MHz) emitted by the satellite into electrical signals that can be processed by the receiver. Its working principle can be broken down into the following core links:

Signal reception and conversion

GPS satellites continuously transmit radio signals carrying timestamps and orbit information in space. These signals pass through the atmosphere to the ground in the form of electromagnetic waves. GPS antennas capture electromagnetic waves through internal radiation units (usually microstrip antennas or helical antennas) and use the principle of electromagnetic induction to convert the energy of electromagnetic waves into weak alternating current signals.

Polarization matching

The signals emitted by GPS satellites are right-hand circularly polarized (RHCP) waves, so GPS antennas need to be designed with the same polarization method to maximize signal reception (if the polarization does not match, the signal will be severely attenuated). This is why the directional design of GPS antennas needs to adapt to the circular polarization characteristics to ensure efficient reception when the satellite position changes (such as the satellite rises from the horizon to the zenith).

Gain and directivity optimization

Gain: GPS antennas concentrate the received energy in a specific direction (usually the zenith and the area above the horizon) by designing the shape of the radiating unit (such as the size of the microstrip patch and the feeding method) and the reflector structure, thereby improving the signal strength (the unit of gain is dBi, the gain of ordinary civilian antennas is about 2-5dBi, and the gain of high-precision antennas can reach 8-15dBi).

Directivity: Civilian GPS antennas are mostly hemispherical directivities (covering the zenith and most of the sky), ensuring that signals from multiple satellites (at least 4) are received at the same time; antennas for special scenarios (such as vehicles) may be optimized to be directional toward the sky ahead to reduce ground clutter interference.

Filtering and anti-interference

High-quality GPS antennas will integrate bandpass filters, allowing only GPS signals around 1575.42MHz to pass through, suppressing interference from other frequency bands (such as mobile phone signals and WiFi signals); some high-precision antennas will also adopt anti-multipath interference designs (such as choke structures) to reduce the impact of ground reflection signals on positioning accuracy (multipath effects will increase positioning errors).

Recommended application of GPS antenna

According to the requirements of different scenarios (such as positioning accuracy, environmental adaptability, and installation method), the selection and application scenarios of GPS antennas can be divided into the following categories:

1. Civilian consumer applications (accuracy 1-10 meters)

In-vehicle navigation

Recommended type: small patch GPS antenna (built-in in the car center console or rearview mirror), or external magnetic antenna (attached to the roof).

Features: small size, low cost, support wide voltage (12-24V), adapt to the vehicle vibration environment, partially integrate Beidou (BDS) and other multi-system (GNSS) reception to improve signal stability.

Typical products: Huaxin Antenna's in-vehicle GNSS combination antenna, supports GPS + Beidou + GLONASS multi-bands, has a stable phase center, and is suitable for in-vehicle navigation and fleet management.

Portable devices

Applications: smartphones, smart watches, sports cameras, drones (civilian).

Recommended type: micro ceramic patch antenna (size <10mm×10mm), integrated inside the device.

Features: low profile, lightweight, suitable for miniaturized design of equipment, moderate receiving sensitivity (about -160dBm).

2. Industrial and industry-level applications (accuracy 0.1-1 meter)

Surveying and geographic information

Applications: engineering surveying, land rights confirmation, drone aerial survey.

Recommended type: high-precision GNSS measurement antenna (such as choke antenna), supporting multi-band (L1/L2/L5) and carrier phase measurement.

Features: small phase center deviation (<1mm), strong anti-multipath interference ability, high gain (8-15dBi), suitable for static or dynamic high-precision positioning.

Typical product: Trimble's Zephyr Geodetic antenna, widely used in professional surveying equipment.

Intelligent transportation and Internet of Vehicles

Applications: autonomous driving (L2-L4 level), fleet monitoring, ETC positioning assistance.

Recommended type: All-in-one integrated antenna (GPS+5G+WiFi), with high protection level (IP67/IP69K), adaptable to high temperature, vibration, and rain environment.

Features: Support centimeter-level positioning (with RTK differential technology), fast signal switching, strong anti-interference ability (such as suppressing interference from vehicle-mounted electronic equipment).

3. Special scenario applications

Aerospace

Applications: aircraft navigation, satellite communication ground station.

Recommended type: high-gain directional GPS antenna (such as parabolic antenna), or wide-beam omnidirectional antenna (covering the sky hemisphere).

Features: resistant to extreme temperatures (-55℃ to +85℃), radiation resistance, and extremely high signal stability (loss rate <0.01%).

Harsh environment (such as ocean, mine)

Applications: ship navigation, mining equipment positioning.

Recommended type: waterproof and corrosion-resistant antenna (metal shell, IP68 protection), with external high-gain antenna (extend the feeder to the area with good signal).

Features: Anti-salt spray, anti-vibration, adaptable to humid and dusty environments, ensuring that signals can still be received in scenes with more obstructions (such as mine tunnels).

Summary

The core of the GPS antenna is to efficiently capture satellite signals and convert them into electrical signals. Its performance (gain, polarization, anti-interference) directly affects positioning accuracy and stability. When choosing, you need to give priority to multi-system compatibility (GNSS), anti-interference ability and environmental adaptability according to the scene requirements (accuracy, environment, device size). Choke coils or professional measurement antennas are recommended for high-precision scenes, while consumer-level scenes focus on miniaturization and cost.