Choosing the Right GNSS Receiver
A GNSS receiver is the user interface portion of any Global Navigation Satellite System (GNSS). Receivers search for and process the signals transmitted by satellites to determine the user’s position, velocity, and precise time (PVT). While individual GNSS receivers will be tailored specifically to the different systems available, and to the applications for which they’re being used, the basic structure of a GNSS receiver is as follows:
- Antenna: The antenna captures GNSS signals, along with possible noise and interference.
- Front-End: The front-end of a receiver down-converts, filters, amplifies, and digitizes signals captured by the antenna.
- Baseboard Signal Processing: Many signal processing sequences are used to search for, secure, and track the different signals.
- Applications Processing: Depending on the application, the receiver processes the GNSS information in order to provide meaningful output to the user.
There are a wide variety of available, and choosing the right GNSS receiver is critical to the success of your project. Different receivers will yield different performances, and the choice that you make should depend largely on several factors including the target application, receiver features, environment, performance, accuracy, power consumption, and cost.
For example, single-frequency receivers can provide a level of accuracy that is appropriate for many applications, and are often available at a low cost. However, if more precise positioning is required, receivers that offer multi-frequency support and differential positioning modes may be better suited.
GNSS Receiver Selection
Your accuracy requirements will differ depending on your specific needs, and understanding these requirements is critical to choosing the right receiver. Receiver accuracy will depend on what signals are tracked, how precisely the receiver measures these signals, and what, if any, correction sources the receiver can accept. Code-only receivers are limited to meter-level accuracy, whereas receivers that provide accurate carrier-phase measurements allow for centimeter-level position information. This accuracy correlates directly to the accuracy of the final solution.
In terms of correction sources, the most accurate receivers will accept both locally-generated and RTK corrections to achieve accuracy levels within centimeters. It’s also important to make sure your GNSS receiver is compatible with corrections from other manufacturers.