What Is GNSS Antenna , GPS GNSS Antenna
What Is GNSS Antenna
GNSS (Global Navigation Satellite System) is a generic term that refers to a collection of satellite navigation systems, including the American GPS (Global Positioning System), the Russian GLONASS, the European Galileo, the Chinese BeiDou, and others. A GNSS antenna is designed to receive signals from all these satellite navigation systems and provide accurate location, velocity, survey , and time information to the user , GNSS antenna is also called survey antenna .
Difference Bewteen GPS Antenna And GNSS Antenna
A GPS (Global Positioning System) antenna is specifically designed to receive signals only from the GPS constellation of satellites, which is operated by the United States government. GPS is the most widely used satellite navigation system globally and is commonly used for navigation, positioning, and timing applications.
So GNSS antennas include GPS antennas, GNSS antennas cover more frequency bands, and GPS antennas are more specialized and optimized for GPS signals only.
What Is Dual-Band , Multi-Band GNSS Antenna
GPS, Beidou, Glonass, and Galileo global navigation satellite systems (GNSS) each has its own network of satellites and ground-based infrastructure.
Different GNSS antennas used for these systems use different frequency bands. GPS and Galileo use L1 and L5 frequency bands, while Beidou uses B1, B2, and B3 frequency bands, and Glonass uses G1 and G2 frequency bands. GPS currently has the largest number of satellites in orbit, followed by Glonass, Beidou, and Galileo. This affects the accuracy and availability of each system in different regions and environments.Therefore, antennas designed for one system may not be compatible with another system.
Dual GNSS antenna means it could work at two different global navigation satellite systems , multi-band GNSS antenna means it could work at two or more different global navigation satellite systems.
Why GNSS Antenna Also Called Survey Antenna
GNSS antennas are often called surveying antennas because they are commonly used in surveying applications to obtain accurate and precise positioning information. Surveying involves measuring and mapping the Earth’s surface to determine the location and shape of natural and man-made features, such as buildings, roads, and topography.
GNSS antennas are an essential tool in modern surveying because they can receive signals from multiple GNSS satellites simultaneously, allowing for more accurate and reliable positioning data. These antennas are designed to be highly sensitive and low-noise, which helps them to pick up weak satellite signals and reduce interference from other sources.
Furthermore, GNSS antennas used for surveying applications are often designed with high-precision features such as multi-path rejection, phase center stability, and antenna calibration, which are important for obtaining accurate positioning information in challenging environments.
The term “surveying antenna” is often used to refer to GNSS antennas because they are commonly used in surveying applications to provide accurate positioning information. However, GNSS antennas have many other applications beyond surveying.
Difference Between Active GNSS Antenna And Passive GNSS Antenna
Active and passive GNSS antennas are two types of antennas used in Global Navigation Satellite System (GNSS) applications. The main difference between active and passive GNSS antennas is that active antennas require external power to operate, while passive antennas do not.
Active GNSS antennas have built-in electronics that amplify the received GNSS signal, which can help to overcome signal loss due to cable attenuation or long cable runs. Active antennas also have a lower noise figure, which means that they can receive weaker signals than passive antennas. Active antennas are typically more expensive than passive antennas due to the added electronics.
Passive GNSS antennas, on the other hand, do not have any built-in electronics and rely on the GNSS receiver to amplify the received signal. Passive antennas are simpler and less expensive than active antennas but may have higher signal losses due to cable attenuation or long cable runs. Passive antennas are more commonly used in applications where cost is a primary consideration, such as in consumer GPS devices.
The main difference between active and passive GNSS antennas is that active antennas require external power and have built-in electronics, while passive antennas do not. The choice between the two types of antennas depends on the specific application and requirements, such as cost, signal strength, and cable length.
How Does GNSS Antenna Work
A GNSS antenna works by receiving radio signals transmitted by the navigation satellites in space. The antenna converts the received electromagnetic waves into electrical signals that can be processed by a GNSS receiver to determine the antenna’s location, velocity, and time information.
The antenna’s design is critical to its performance, as it needs to be optimized for receiving signals from multiple satellite systems that transmit signals at different frequencies and with different modulation schemes. Typically, a GNSS antenna consists of a radiating element that is connected to a feedline and a ground plane. The radiating element is responsible for capturing the satellite signals, while the feedline and ground plane help to direct and shape the signal.
When a GNSS antenna receives a signal from a satellite, the electromagnetic waves induce a voltage in the antenna’s radiating element, which is then amplified and processed by the GNSS receiver. The receiver compares the received signals from multiple satellites to determine the antenna’s precise location and time information.
To ensure optimal performance, GNSS antennas need to be carefully placed and oriented, taking into account the surrounding environment, such as buildings, trees, and other obstructions, which can cause signal reflections and multipath interference.
GNSS antennas play a critical role in providing accurate location and timing information for a wide range of applications, including navigation, surveying, mapping, and timing synchronization.
Components of a GNSS antenna
The following are the key components of a GNSS antenna:
- Radiating element : The radiating element is the part of the antenna that receives the signals from the GNSS satellites. It is usually a patch or helical element that is designed to resonate at the frequencies used by the GNSS system.
- Ground plane : The ground plane is a conductive surface that is located beneath the radiating element. It helps to reflect the signals received by the antenna towards the radiating element.
- Low noise amplifier (LNA): The LNA is a component that amplifies the weak signals received by the antenna before they are sent to the GNSS receiver. The LNA is located close to the antenna to minimize losses in the coaxial cable that connects the antenna to the receiver.
- Filtering circuit : The filtering circuit is a component that filters out unwanted signals and noise from the received signals. It helps to improve the signal-to-noise ratio of the signals sent to the GNSS receiver.
- Radome : The radome is a protective cover that is placed over the antenna to protect it from the environment. It is usually made of a dielectric material that allows the GNSS signals to pass through.
- GNSS antenna Connector : The connector is a component that is used to connect the antenna to the GNSS receiver. It is usually a standard coaxial connector such as an SMA or TNC connector.
- GNSS antenna cable : The cable need used to connector the GNSS antenna and the receiver , both end is SMA or TNC connector .
Together, these components work together to provide a GNSS antenna with the ability to receive and amplify weak signals from GNSS satellites, filter out unwanted noise, and send the clean signals to the GNSS receiver for processing.
Types Of GNSS Antenna
There are several types of GNSS antennas, each with its unique design and performance characteristics. Some of the most common types of GNSS antennas include:
- Patch Antennas : These antennas are flat, rectangular or circular in shape and consist of a patch of conductive material placed over a ground plane. Patch antennas are widely used in GNSS applications due to their compact size, low profile, and excellent performance.
- Helical Antennas : Helical antennas consist of a wire wound into a helix shape, with a ground plane at one end and a feed point at the other. They are commonly used in applications where high accuracy is required, such as surveying and geodetic measurements.
- Dipole Antennas : Dipole antennas consist of two conductive elements, each a quarter-wavelength long, oriented perpendicular to each other. They are commonly used in handheld GNSS receivers due to their small size and low cost.
- Microstrip Antennas : Microstrip antennas consist of a patch of conductive material placed on a dielectric substrate, with a ground plane on the other side. They are commonly used in applications where low profile and high gain are required.
- Spiral Antennas : Spiral antennas consist of a wire wound in a spiral shape, with a ground plane on one side and a feed point on the other. They are commonly used in applications where high gain and wideband performance are required.
- External GNSS Antenna : It’s a separate device that is physically mounted outside a device or vehicle, such as on the roof of a car or on the exterior of a building, and transmits these signals to the GNSS receiver inside the device or vehicle.
- Interal GNSS Antenna : It’s built into the device itself, such as a smartphone or a portable navigation device. The internal antenna is typically smaller and less powerful than an external antenna, but it is more convenient because it is already integrated into the device.
- Smart GNSS Antenna : It’s a type of antenna that has integrated signal processing and intelligence capabilities. Unlike traditional antennas that simply receive and transmit signals, smart GNSS antennas are designed to analyze and process the signals they receive, providing more accurate and reliable positioning information.
- RTK GNSS Antenna : RTK GNSS (Real-Time Kinematic Global Navigation Satellite System) is a high-precision positioning technology that uses a network of GNSS reference stations to provide accurate and real-time positioning information.It’s specifically designed for RTK applications, equipped with advanced processing capabilities and additional components such as a data link and a controller. RTK GNSS antennas are used in applications that require high-precision positioning, such as surveying, mapping, construction, precision agriculture, and mining. They can provide positioning accuracy down to a few centimeters, making them ideal for applications that require high levels of precision and accuracy.
Each type of GNSS antenna has its unique advantages and disadvantages, and the choice of antenna depends on the specific application requirements, such as the required accuracy, environment, and cost.
Characteristics of GNSS Antennas
Some of the key characteristics of GNSS antennas include:
- Frequency range : GNSS antennas operate in the frequency range of 1.1 GHz to 1.6 GHz.
- Gain: The gain of a GNSS antenna determines how effectively it can receive signals. GNSS antennas typically have a gain of between 0 dB and 5 dB.
- Polarization : The polarization of a GNSS antenna determines how the antenna receives signals. GNSS antennas typically use circular polarization to receive signals from all directions.
- Radiation pattern : The radiation pattern of a GNSS antenna describes how it receives signals from different directions. GNSS antennas typically have an omnidirectional radiation pattern, meaning they can receive signals from all directions.
- Impedance : GNSS antennas are designed to have an impedance of 50 ohms, which is the standard impedance for most RF devices.
- Size : GNSS antennas can be relatively small, with many antennas measuring less than 10 cm in length.
- Mounting options: GNSS antennas can be mounted in a variety of ways, including on a mast or tower, on a roof, or on a vehicle.
- Environmental resistance : GNSS antennas are often exposed to harsh outdoor environments and must be designed to withstand environmental factors such as temperature, moisture, and UV radiation.
- Cost : The cost of a GNSS antenna can vary depending on the specific characteristics and features of the antenna. In general, GNSS antennas tend to be relatively affordable compared to other types of antennas.
How To Choose GNSS Antenna
There are several factors to consider:
- Frequency range: Choose an antenna that supports the frequencies used by the GNSS system you plan to use (e.g. GPS, GLONASS, Galileo, BeiDou). For example, a GPS antenna will typically operate in the L1 and L2 frequency bands.
- Gain: The gain of an antenna determines how well it can receive signals from the GNSS satellites. Higher gain antennas can receive weaker signals and can provide better accuracy in challenging environments such as urban canyons or under dense foliage. However, higher gain antennas may also be more susceptible to multi-path interference.
- Radiation pattern: The radiation pattern of an antenna determines how the signals are transmitted and received. The most common types of radiation patterns for GNSS antennas are hemispherical and patch antennas. A hemispherical antenna is suitable for applications where the antenna is mounted at a high elevation angle, while a patch antenna is better suited for low elevation angle applications.
- Size and weight: The size and weight of the antenna may be an important factor to consider, especially for applications where space is limited or where portability is important.
- Mounting options: Consider the mounting options for the antenna. Will it be mounted on a roof, a mast, or a vehicle? Make sure the mounting hardware is appropriate for your application.
- Environmental factors: Consider the operating environment of the antenna. Is it going to be exposed to harsh weather conditions or extreme temperatures? Choose an antenna that is designed to operate in these conditions.
- Price: GNSS antennas vary in price depending on the features and performance. Determine the features and performance requirements for your application and choose an antenna that meets those needs within your budget.
Overall, when choosing a GNSS antenna, consider the specific requirements of your application and choose an antenna that meets those requirements while staying within your budget.
How To Mount GNSS Antenna
Choose a suitable location for the antenna: The antenna should be placed in a location that has an unobstructed view of the sky to receive signals from the GNSS satellites. Avoid locations with tall buildings, trees, or other obstructions that could block the signal.
- Mount the antenna: Depending on the type of antenna and the application, the antenna can be mounted on a roof, a pole, a mast, or a vehicle. Follow the manufacturer’s instructions for mounting the antenna securely and make sure the mounting hardware is appropriate for the application.
- Connect the cable: The GNSS antenna is connected to the GNSS receiver or the modem through a coaxial cable. Make sure the cable is the correct length and is routed in a way that avoids sharp bends or kinks that could damage the cable.
- Ground the antenna: To protect against lightning strikes, it is important to ground the GNSS antenna. Use a grounding block or lightning arrestor to connect the antenna to a grounding rod or a building’s grounding system.
- Configure the GNSS receiver: Once the antenna is installed, configure the GNSS receiver to recognize the antenna and start receiving signals. Follow the manufacturer’s instructions for configuring the receiver and make sure the receiver is compatible with the antenna.
- Test the system: After installing the antenna and configuring the receiver, test the GNSS system to make sure it is functioning properly. Check the signal strength and the accuracy of the positioning data to ensure that the system is working as expected.
Overall, installing a GNSS antenna requires careful planning and attention to detail to ensure that the antenna is installed in a suitable location, securely mounted, properly grounded, and connected to the receiver or modem correctly.
Applications Of GNSS Antenna
GNSS antennas are used in a variety of applications that rely on positioning, navigation, and timing information provided by GNSS satellites. Here are some of the most common applications of GNSS antennas:
- Navigation: GNSS antennas are used in navigation systems to determine the location, speed, and direction of a moving object, such as a vehicle, ship, or aircraft.
- Surveying and Mapping: GNSS antennas are used in surveying and mapping applications to accurately measure the position of objects on the ground, such as land boundaries, construction sites, and natural resources.
- Agriculture: GNSS antennas are used in precision agriculture to optimize crop yield and reduce waste by providing accurate location information for planting, fertilizing, and harvesting.
- Transportation: GNSS antennas are used in transportation systems to monitor the location and movement of vehicles, improve traffic flow, and enhance safety.
- Timing and Synchronization: GNSS antennas are used in timing and synchronization applications, such as telecommunications, power grids, and financial trading, to ensure accurate and synchronized timekeeping across multiple locations.
- Search and Rescue: GNSS antennas are used in search and rescue operations to locate lost or distressed individuals or vessels.
- Military and Defense: GNSS antennas are used in military and defense applications to support navigation, guidance, and targeting for aircraft, ships, and ground vehicles.
Overall, the applications of GNSS antennas are wide-ranging and varied, and they play a crucial role in many industries that rely on accurate positioning and timing information.
GNSS Antenna Design
Designing a GNSS antenna can be a complex process that requires expertise in antenna theory, electromagnetic field theory, and circuit design. Here are some general steps that can be followed to design a GNSS antenna:
- Determine the operating frequency: GNSS systems operate at specific frequency bands, so the first step is to determine the frequency band(s) that the antenna will be designed for.
- Choose an antenna type: There are several types of GNSS antennas, such as patch antennas, helical antennas, and spiral antennas. The choice of antenna type will depend on factors such as the desired gain, size, and radiation pattern.
- Define the antenna specifications: This includes parameters such as the gain, bandwidth, polarization, and radiation pattern. The specifications will depend on the intended application and the operating environment.
- Use software tools for antenna design: There are several software tools available for designing antennas, such as HFSS, CST, and FEKO. These tools can simulate the behavior of the antenna and optimize the design parameters for the desired specifications.
- Fabricate and test the antenna: Once the design is complete, the antenna can be fabricated and tested to verify its performance. This includes measuring parameters such as the return loss, gain, and radiation pattern.
It’s important to note that designing a GNSS antenna can be a complex and iterative process, and may require multiple iterations to optimize the design for the desired performance. Therefore, it’s recommended to have a strong background in antenna theory and access to simulation tools and testing equipment.
We have professional team and engineers that have more than 20 years experience for the GNSS antenna design, if you have such inquiry, welcome to contact us.