When it comes to selecting GNSS frequencies for applications, there are many factors to consider before selecting single or dual-frequency. Some important things to keep in mind during the selection process of choosing single vs. dual-frequency are:
- What kind of testing is being conducted and what results are needed?
- What environment is the testing being conducted in?
- Is beyond visual line of sight (BVLOS) required?
- Is the signal lock frequently lost?
With single-frequency, the receiver is typically limited to decimeter-level accuracy, and will not always provide a fixed position. Single-frequency can be used for general location services, pinpointing dots on a map, and finding a generic location that might be 2 – 4 meters off or more.
It is important to know that when using a single-frequency, there is a risk of more frequent loss of signal, longer convergence time, and will require shorter baselines. Depending on the scenario in which the application is being used, this can be not optimal for reading positioning data between the application and the base station.
- Decimeter-level accuracy when testing in an unobstructed environment, and where BVLOS is not neededGeneral location services
Dual-frequency can minimize errors caused by the ionosphere and troposphere, which contains ionized particles that can have a protruding effect on signals and disrupt them. By mitigating these errors, users can to get centimeter-level accuracy, and faster convergence times to get a fixed position.
Dual-frequency requires more processing power to acquire, track and position. It is typically more expensive and requires special hardware, along with a different antenna that is capable of tracking multiple frequencies.
Providing the same benefits as dual-frequency, triple-frequency is also now available and can potentially improve convergence time, provide even longer baselines and better ionospheric estimation.
- Minimizes errors caused by the ionosphere and troposphere
- Works in more challenging environments with high multipath and numerous signal obstructions
The best environment for use of single and dual-frequency depends on several factors. If users do not require centimeter-level accuracy for their application, then they qualify as a good candidate for single frequency. Dual-frequency helps address multipath, which occurs much more in urban or reflective environments. If it is an environment where the signal lock can be easily lost, such as an area with tall buildings or if the device is used in BVLOS applications, it is recommended to use dual frequency.
Ultimately, selecting an option for GNSS frequency depends on the unique and specific testing factors you are facing. Trimble OEM GNSS provides a wide variety of single, dual and triple-frequency high-precision GNSS receivers to best support your application.