2.1 High Phase Center Stability: The Foundation of Measurement Accuracy

At the core of any precision GNSS antenna is its phase center—the point within the antenna where the received satellite signals are considered to be processed. For accurate measurements, this phase center must remain stable regardless of the satellite’s position in the sky or the antenna’s orientation. A unstable phase center can introduce significant errors, as the antenna’s apparent position shifts relative to the actual ground location being surveyed.

This precision surveying GNSS antenna tackles this challenge through a multi-feed point design and a completely symmetrical antenna structure. The multi-feed point design involves incorporating multiple signal reception points within the antenna, which work in tandem to average out minor variations in signal arrival times. This averaging effect ensures that the phase center remains consistent, even when signals come from extreme angles (e.g., low-elevation satellites near the horizon).

The symmetrical structure, meanwhile, eliminates directional biases. By ensuring that the antenna’s physical and electrical properties are uniform across all axes, it avoids preferential treatment of signals from specific directions. This symmetry is particularly critical in applications where the antenna may be subjected to slight tilts or rotations, such as in mobile surveying units or airborne mapping systems.

The result is a phase center stability that minimizes measurement errors. In practical terms, this means that repeated measurements of the same point will yield consistent results, with deviations often measured in millimeters rather than centimeters. For projects like railway alignment, where even a small error can lead to costly construction mistakes, or in deformation monitoring of dams and bridges, where subtle positional changes must be detected over time, this level of stability is invaluable.

2.2 Tracking in Challenging Environments: Overcoming Obstructions and Signal Weakness

One of the most common challenges in GNSS surveying is maintaining signal reception in environments where satellites are partially or fully obstructed. Urban canyons (areas surrounded by tall buildings), dense forests, and mountainous terrain can block or reflect satellite signals, leading to signal loss or multipath interference (where signals bounce off surfaces before reaching the antenna, causing timing errors).

This antenna addresses these issues through three key design elements: high gain, a wide pattern beam, and excellent reception of low-elevation angle signals.

High gain refers to the antenna’s ability to amplify weak signals. In areas with partial obstructions, satellite signals may be attenuated as they pass through obstacles like tree foliage or building facades. The antenna’s high gain ensures that even these weakened signals are captured and processed effectively.

Wide pattern beam expands the antenna’s field of view, allowing it to receive signals from a broader range of satellite positions. This is particularly useful in urban environments, where satellites directly overhead may be visible, but those at lower angles are blocked by buildings. A wide beam ensures that the antenna can still lock onto the available satellites, maintaining a sufficient number of connections to calculate a precise position.

Low-elevation angle reception is perhaps the most critical feature for challenging environments. Satellites at low elevations (less than 15 degrees above the horizon) are often the only ones visible in deep canyons or dense forests. However, signals from these satellites are more prone to attenuation and multipath interference because they travel through more of the Earth’s atmosphere and are more likely to reflect off nearby surfaces. This antenna is engineered to filter out noise from these low-angle signals while preserving their integrity, ensuring that they contribute meaningfully to position calculations.

In field tests, this antenna has demonstrated its ability to maintain stable connections with 8-10 satellites even in areas where conventional antennas struggle to track 4-5. For example, in a dense urban neighborhood with 30-story buildings, the antenna continued to provide centimeter-level accuracy, whereas a standard antenna reported errors of 1-2 meters due to signal dropouts. Similarly, in forested regions, where canopy cover blocks much of the sky, the antenna’s low-elevation reception allowed surveyors to complete their work without waiting for clear sky conditions.

2.3 Strong Anti-Interference Ability: Mitigating Unwanted Signals

In today’s electromagnetic landscape, GNSS signals face increasing competition from other radio frequency (RF) sources. These include intentional jammers (used illegally to disrupt GNSS in certain areas), as well as unintentional interference from nearby communication towers, radar systems, or industrial equipment. Such interference can corrupt GNSS signals, leading to positioning errors or complete signal loss.

This precision surveying GNSS antenna employs a pre-filtering and multi-stage filtering scheme to combat interference.

Pre-filtering occurs at the front end of the antenna’s signal processing chain, where a band-pass filter allows only the frequencies used by GNSS constellations (e.g., GPS L1 at 1575.42 MHz, BDS B1 at 1561.098 MHz) to pass through, blocking out-of-band signals from the start. This reduces the workload on subsequent filtering stages and prevents strong interference from overwhelming the system.

Multi-stage filtering builds on this by incorporating additional filters at different points in the signal processing pathway. Each stage targets specific types of interference: for example, one stage may focus on suppressing narrowband interference from nearby radio transmitters, while another targets broadband noise from industrial machinery. This layered approach ensures that even complex interference scenarios are managed effectively.

The result is an antenna that can operate reliably in high-electromagnetic-noise environments. In regions near airports (where radar systems emit strong RF signals) or industrial zones (with heavy machinery), the antenna maintains its accuracy, whereas unfiltered antennas may report erratic positions or fail to lock onto satellites altogether. This anti-interference capability is particularly critical for critical infrastructure projects, such as pipeline monitoring or power grid alignment, where reliable positioning data is essential for safety and functionality.

2.4 Compact, Lightweight, and Durable: Designed for Field Conditions

Precision surveying often takes place in harsh outdoor environments, from scorching deserts to freezing mountain tops. An antenna must therefore be rugged enough to withstand extreme weather, physical stress, and prolonged exposure to the elements—all while remaining easy to transport and install.

This antenna excels in this regard, with a design that prioritizes compactness, lightweight construction, low wind resistance, and robust environmental protection.

Compact and lightweight: The antenna’s small form factor (typically measuring less than 15 cm in diameter and weighing under 500 grams) makes it easy to carry in field kits and mount on surveying poles, drones, or vehicles. This is a significant advantage over bulkier antennas, which can be cumbersome to transport and may require additional support structures.

Low wind resistance: Its streamlined shape minimizes drag, making it suitable for use in high-wind environments such as open plains or coastal areas. This reduces the risk of the antenna being dislodged or tilted during measurements, which could introduce errors.

Environmental protection: The antenna boasts an IP67 protection rating, meaning it is dust-tight and can withstand immersion in up to 1 meter of water for 30 minutes. This makes it resistant to rain, snow, and dust, ensuring reliable operation in inclement weather. Additionally, the outer casing is treated to resist ultraviolet (UV) radiation, preventing degradation from prolonged sun exposure. This UV resistance is crucial for antennas used in sunny climates, where UV rays can cause plastic casings to become brittle over time, compromising both structural integrity and performance.

These durability features ensure that the antenna can be deployed in a wide range of field conditions without sacrificing accuracy. Whether used in the Sahara Desert, the Arctic tundra, or a tropical rainforest, it remains operational, reducing downtime and ensuring that surveying projects stay on schedule.