What is the Difference Between GNSS and GPS?

GNSS and GPS are satellite-based systems that provide precise location information to devices on earth. These satellites are located in geosynchronous orbits and synchronize their radio signals. GNSS receivers process the signals to calculate a user’s location in real-time. These receivers analyze the satellites’ position, velocity, and direction. GNSS and GPS are compatible, but each has unique features and capabilities.

GNSS is a satellite-based augmentation system

A satellite-based augmentation system (SBAS) can improve the performance of a GNSS system by providing ranging, integrity, and correction information. SBAS systems consist of sensor stations and ground infrastructure for computing the integrity and correction data and relaying the data to receiving devices. Most countries have at least one SBAS GEO satellite.

The augmentation infrastructure can be private or publicly funded. Existing precision GNSS users can maintain their reference station or subscribe to a commercial service. The augmentation infrastructure market is expected to grow rapidly through the next decade as more users opt to use this technology. 

Among the significant uses of SBAS systems are for aircraft guidance. The technology enables pilots to land an aircraft safely and enables the pilot to control the aircraft to navigate it in the air. Moreover, SBAS systems can assist spacecraft navigation, including satellite-based air traffic.

DGPS is an enhancement to GNSS

DGPS is an enhancement to GNOSS (Global Navigation Satellite System). It uses a network of fixed ground-based reference stations to provide better location accuracy. These reference stations broadcast differential correction signals and use a block-shift technique to compare the user’s location with the reference station’s. Differential GPS can be applied in real-time in the field or post-processed after data has been collected.

DGPS enhances GNSS because the satellites are not necessarily in the same position. A user can be up to 200 nautical miles away from a reference station and still receive accurate position data. But as the user moves further from the reference station, the accuracy of DGPS decreases. This problem is compounded when the user is in poor visibility.

The accuracy of GPS depends on the number of satellites used and on the location of the rover. The accuracy of GPS is improved in open spaces and forested areas. DGPS is less affected by these variables but can still be affected by the distance between the transmitter and the instrument. Its time coordinate system is WGS84, but it can also use local coordinates.

DGPS is a specific enhancement to GNSS and uses different approaches to ensure accuracy. Currently, two of the most popular methods are post-processed DGPS and measurement-domain DGPS. These methods use range corrections, which are more flexible than position-domain DGPS. This method is becoming increasingly popular in chipsets and end devices.

GNSS receivers outsource complex computing processes to the cloud

GNSS receivers can now outsource complex computing processes to the cloud, reducing power consumption on the end device. The process is called snapshot positioning, and it involves performing GNSS receiver processing tasks while the cloud-based service calculates the actual position. The result is that the GNSS receiver can focus on delivering precise navigation data to the end user.

Cloud-based GNSS receivers offer a range of benefits to users, including the flexibility they offer. For example, they can be configured to minimize power consumption by avoiding reboots, which consume significant power. Furthermore, they can support signal-level analysis by storing raw GNSS samples in JSON or the Software-Defined Radio (SDR) metadata standard. 

The cloud-based GNSS receiver can automatically generate assistance information by attaching an approximate location and timestamp to the sensor. It can also use a network of servers and information relays to speed up the acquisition process. By using a cloud-based system, GNSS receivers can now outsource complex computing processes to the cloud, enabling them to be more efficient and reliable.

The energy consumption of a GNSS receiver traditionally varies but has declined dramatically over the past decade. In addition, GNSS receivers typically feature a wide range of configuration options, making it possible for users to optimize power usage and tailor the hardware to specific use cases. For example, the sensitivity of a GNSS receiver is directly related to the length of the signal. Increasing the coherent integration time enables the receiver to detect weaker signals.

Cloud-based GNSS receivers use an Application Programming Interface (API) to connect sensors to the cloud. Afterward, the output results are stored in a database, which can be accessed at any time. The cloud-based GNSS receiver can also be used to create a new job based on a raw GNSS sample file. Input data can include data from nearby GNSS receivers, manual input, or previously-stored information.

GNSS receivers consume more power

GNSS receivers have historically consumed a significant amount of power. However, this has declined dramatically in the past decade. Today, GNSS receivers are more energy efficient, with some models offering a variety of settings to adapt to specific use cases and optimize power consumption.

The main reason for this difference is that GNSS receivers use different frequency bands than GPS. These devices need more power to seek connections across different sources, which means they consume more power. In addition, GNSS receivers cannot go into power-saving sleep modes. Click here to learn more about the difference between these two products!

GNSS systems have established a network of stations around the earth’s equator to monitor and control the orbits of the satellites. These stations transmit data about the location of the satellites using the L1 carrier wave. It is more accurate than GPS, which requires up to four satellites to provide accurate and reliable position data.

One use of GNSS technology is for tracking public buses. Many people rely on public transportation to work, social activities, and even sports events. Most public transportation agencies have installed GNSS receivers in buses so that passengers can check the status of their buses in a control center. These devices also display expected arrival times at bus stops.

Although dual-frequency GNSS systems are the most widely used in professional settings, most of these receivers will be replaced by triple-frequency systems when Galileo commercial service becomes available. These new technologies promise better accuracy, lower power consumption, and faster initialization.