GNSS Simulator basics | GNSS Simulator specifications,Vendors

This page covers GNSS simulator basics and mentions GNSS simulator specifications and GNSS receiver test setup. It also mentions vendors of GNSS simulator.

About GNSS: The term GNSS refers to Global Navigation Satellite System. It is the technology which provides navigation and other services to the users across the globe. There are two major elements in the GNSS system viz. space segment and ground segment. The space segment employs constellation of satellites. These satellites broadcast signals which are received and processed by GNSS receivers known as ground segment. These GNSS receivers determine location as well as speed/time for the GNSS users within the coverage region of the satellites.

Other navigation systems include GPS, Galileo, GLONASS etc. Due to vast number of applications of GNSS, it has become essential to perform through testing of GNSS receivers in order to provide best quality user devices. The GNSS and other navigation systems are tested either in the field or in the lab.

The lab testing is carried out using GNSS simulator. Following are the advantages (i.e. merits) of GNSS simulator over live field testing using actual GNSS constellations.
• GNSS simulator provides complete control over constellation which is not available in live testing.
• Lab testing can siulate environmental conditions and also can be changed to test vivid severity levels.
• The lab tests can be repeatable while live testing is not repeatable.
• The testing can be done along with constellation errors.
• Lab testing is cheaper compare to field testing.
• The testing can be done with any location on earth with different times of past, present and future scenarios.
• The testing can be conducted in secured environment without any unintended interference as well as multipath signal effects.

GNSS Simulator Receiver Test setup

GNSS Simulator definition: The device which provides all the GNSS simulation conditions as available in live field scenarios with satellite constellations and other environment conditions is known as GNSS simulator. It is also known as GNSS RF Simulator.

The GNSS simulator provides ultimate platform which emulates actual environmental conditions including satellite and vehicle motion in order to test GNSS receivers. The figure-1 depicts GNSS receiver test setup. As shown GNSS receiver can be either direcly connected with GNSS simulator using RF cable or both can communicate using RF Antennas. Often GNSS simulation software is installed in the laptop or PC connected with GNSS simulator hardware. There are GNSS Signal generator with built in software loaded to configure various system parameters. The test will ascertain that RF part and processing part of GNSS receiver are working satisfactorily.

GNSS Simulator specifications

Following are the typical specifications of GNSS Simulator one need to consider while selecting simulator for GNSS receiver testing.
• Multiple satellites and constellations user configurable
• Remote control using USB/Ethernet/RS232 interface
• 1 PPS output
• Storage to record data
• Output signal level: about -83dBm to -115dBm
• Number RF channels: 1/2/3
• Output frequencies: 1561.098 MHz/1575.4 MHz/1602 MHz

GNSS Simulator Vendors

Following table mentions GNSS Simulator vendors with their product details.

Wireless test and measurement equipments

MIMO channel emulator
CMU200 vs CMW500
WLAN Test and Measurement Equipments
Wireless Sniffer
Bluetooth test tools
LTE test tools