What is QZSS?
Do I Need QZSS?
What is QZSS?
ystem is a satellite-based augmentation system (SBAS) developed by the Japanese government.
The main focus of QZSS is to enhance the United States operated Global Positioning System (GPS) in the Asia-Oceania regions.
QZSS is also known as 'Michibiki' - which means 'guide' or 'show the way'
The QZSS concept is quite unique when compared to the similar arrangements shared by GPS, GLONASS and Galileo.
QZSS is designed to augment another satellite navigation system (GPS).
QZSS satellites occupy inclined elliptical geosynchronous (Tundra) orbits for optimal high-elevation visibility in the coverage area.
Primarily intended to increase GPS availability in Japan's numerous urban canyons, where only satellites at very high elevations are visible.
Secondary functions include performance enhancements increasing the accuracy and reliability of GPS derived navigation solutions.
All Quasi-Zenith Satellites transmit signals compatible with the GPS L1C/A signal, as well as the modernized GPS L1C, L2C and L5 signals.
GPS + QZSS delivers improved positioning performance and improved reliability when compared to GPS alone.
QZSS receivers can resolve ionospheric errors by combining multiple frequencies (L1 with L2 or L5).
QZSS Tundra Orbit
The QZSS system will provide the following services:
Satellite Positioning Service
- Provide service similar to GPS with improved coverage in urban and mountain areas.
Sub-Meter Level Augmentation Service
- Improved accuracy positioning in the 2-3 meter range.
Centimeter Level Augmentation Service
- Highly accurate positioning in the 10 centimeter range.
Position Technology Verification Services
- Will provide an application demonstration for new positioning technology.
Short Message Delivery Service
- Provides users in the field with rescue, disaster and crisis management services.
The QZSS constellation consists of three satellites in a periodic Highly Elliptical Orbit (HEO) with a fourth satellite in a geo-stationary orbit.
All three HEO satellites follow the same path so that at least one of them is always near the zenith over Japan ('quasi-zenith').
When viewed from Tokyo, these satellites will remain overhead with an elevation:
above 70° for 8 hours each day.
above 50° for 12 hours each day.
above 20° for 16 hours each day.
QZSS can be used in any Asia-Oceania region with a longitude close to Japan:
Hours per day at least one QZSS satellite is above 40° elevation
QZSS service officially started on November 1, 2018 with a four satellite constellation.
A fully independent QZSS service consisting of seven satellites is planned for 2023
View a list of available QZSS satellites
Choose desired QZSS Satellite (
) below to view current location:
Do I Need QZSS?
modern GPS receivers (GPSr) are able to use both QZSS and GPS satellites.
Simultaneous use of QZSS and GPS provides improved coverage, performance and reliability when compared to GPS alone.
For locations in or near Japan, the benefits of using QZSS while navigating
urban canyons or mountainous areas