HOW DOES THE TECHNOLOGY BEHIND AV WORK? (Part Two)

For most of us, it is magic how autonomous vehicles operate. Let us dissect this magic.

Autonomous vehicles operate thanks to the use of a global navigation satellite system (GNSS). This is a satellite constellation in orbit which transmits timing and positioning data modulated onto radio carrier waves. These signals can then be used by receivers to determine their position, velocity, attitude or synchronise timing. Currently, there are four GNSS systems:

• GPS - US fully operational system with 31 satellites in orbit.
• GLONASS - Russian fully operational system with 24 satellites in orbit
• Galileo - EU system expected to be fully operational in 2020 with 30 satellites in orbit.
• BeiDou - Chinese system expected to be fully operational in 2020 with 35 satellites in orbit.

The signal sent from the satellites typically consists of one or more pseudo-random ranging codes (refers to the receiver and satellite clock errors contaminating the estimated range) and a navigation message which are modulated onto a carrier wave. The navigation message contains the status and precise orbital data of the satellite itself (ephemeris data), crude orbital data and status of other satellites (almanac data) and the GPS time.

In order for Autonomous Vehicles to properly work, more is needed than GNSS. That is why GNSS will be augmented with other systems in order to meet the Required Navigation Performance. This will be discussed in a second part of this topic, stay tuned!

Don't forget to take a look on Technology (Part One)