The Galileo Test and Development Environment (GATE) is a ground-based realistic test environment for developers of receivers, applications, and services for the future satellite navigation system Galileo. This will enable developers to perform realistic field tests of hardware and software for Galileo at an early stage.

Currently under construction, GATE will begin emitting Galileo signals via six Earth-fixed transmitters in the Bavarian Alps in southeast Germany this spring–several years before Galileo becomes fully operational.

As GATE is a real-time system, it is necessary to feed the navigation message in real-time to the transmitters. Therefore they must be flexible in signal generation and adaptive to changes in signal structure.

The transmit segment comprises six ground-based transmit stations. They are also equipped with stable atomic clocks. These transmitters will emit all frequencies foreseen for Galileo.

Berchtesgaden is surrounded by mountains reaching above 2,000 meters. Test Area. Located in the region of Berchtesgaden in Bavaria, the test area extends over 65 square kilometers, with a core test area of 25 square kilometers. The two monitoring stations are located at an exposed central position within the test area. The establishment of the transmitters on well exposed positions enables signal emission with average elevation angles of 10 to 15 degrees from a user’s point of view.

ground-based ranging test bed at Yuma in the 1970s proved the concept of satellite navigation, no one doubts that Galileo will work from a conceptual point of view. It consists of four segments:

GATE covers three major mission objectives: signal experiments, receiver testing, and user applications. S. However, it is still an ambitious technological project, introducing a signal structure far more sophisticated than the GPS C/A Code. While the U.

The processing facility and monitor receiver were developed by IfEN GmbH.

It monitors navigation signals performs time synchronization of all system clocks, and generates navigation messages and, steering commands to the transmitters. The mission segment consists of two monitoring stations and a processing facility.

First Test Results

Integration tests of the frequency boards are also very promising with respect to performance and functionality. Qualification testing of the splitter showed very good compliance to the specifications. To separate the three frequency bands E5, L1, and E6 from the Galileo/GATE signal spectrum, one single splitter board is required for distributing the Galileo signals to the different GATE frequency boards. All three boards together form a GATE frequency board. The testing of the GATE receiver up to now mainly comprised interface, functional, and performance tests of the front end, signal conversion, and digital baseband board.

The support segment comprises the mobile GATE user terminal with the user receiver, the mission support facility, and the signal laboratory.

It performs the appropriate preparation, that is, simulation and planning of GATE experiments with dedicated software tools, as well as the provision of the user terminals equipped with a combined Galileo/GPS receiver.

Five transmit stations will be set up using already existing infrastructure–TV or mobile phone masts–and one fully autonomous transmit station has been established.

Major building blocks are the control computer, a rubidium reference clock unit, and three mostly identical signal generation units, one for each band, followed by an RF amplifier section.

Except for the voltage controlled oscillator generating the RF carrier frequency, the signal generators are based on identical hardware, providing a high degree of freedom to configure by software according to channel setup requirements. The signal generators developed by Astrium GmbH are designed to generate simultaneously the Galileo navigation signals in the E5,, E6 and L1 bands.

The transmit antenna is a quadrifilar helix antenna with a radom housing and heating capability to ensure de-icing in cold weather.

These tests included performance, thermal, and electormagnetic compatibility testing for the certification process. Formal transmit segment acceptance testing of the signal generator unit, the transmit antenna, and the completely integrated transmit segment rack has been finalized. Based on successful test results, recurring unit and antenna approval were given in September 2006 for the start of system assembly and integration.

It monitors and controls the entire GATE system; hosts and operates the control center, which serves as operational node including mission planning; hosts and provides GATE system time; and archives GATE mission data.

The control segment includes the monitoring and control facility, the archiving and data server, and the time facility.

The monitor antenna is also based on a quadrifilar helix design. During unit testing, the complete receiver antenna was measured in an anechoic chamber with respect to gain and voltage standing wave radio characteristics, comprising also the utilized low noise amplifier (LNA).

The LNA was designed to withstand hard electromagnetic environmental conditions and spurious emissions, since both GATE receiver antennas will be mounted on a large telecommunication mast, housing different mobile phone providers and emitting antennas. The receiver qualification tests showed good compliance of the antenna design and characteristics to the specification.