SIMBAD was a research project which studied and developed a communication system which makes it possible to transmit data from vehicles in motion on the ground, at any point within the coverage of the satellite. It planned a specific communication case between a light in-land vehicle in movement and a helicopter in the air.
The main objectives of this project were:
- Design and development of a communication system which allows the data transmission from in-land vehicles in movement in any satellite covering point.
- As an innovative point, to stress the study of systems which allow IP connectivity in broadband for this kind of vehicle.
- The manufacture of a new product destinated to the application called "SATCOM on the move".
- To manufacture this new product in Spain, with the subsequent promotion of the industry in this country.
- To develop new applications for satellite communications (in emergency situations, civil protection and traffic control, among others).
The technical part of project was divided in several parts:
PT 1: Secifications and Design of the system
PT 2: Design of the system:
- Design of the RF for SAT
- Design of the pointing system
- Radio Channel and Hub
- Communications air-land
PT 3: Implementation of the components
PT 4: Integration and tests
SIMBAD was devoted to research and develop an innovative solution which intends to satisfy a real necessity in communications from vehicles in moving frameworks.
An application test of communications between in-land vehicle and helicopter was carried out.
Main technical results were:
Analysis of solutions for the interconnexions between helicopter and vehicle in movement (DVB-T, DVB-H and Wimax):
- Technology which allow benefits of quality and maximum link range
- Use of complex compresion standards as JPEG and MPEG-2/4
- Availability of frequency bands, characteristics of propagation in these bands and their impact in the transmission power and the functioning capacity in multipath environments with mobility.
Use of an OFDM modulated technology. This technology is Wimax, because it has free frequencies which has no need of license
- In the lower frequencies of Wimax, it is possible to reach communication up to 10 kilometers within a power range between 1 and 2 Watts.
- It is considered to use the mobile version of the Wimax standard to release problems derived from Doppler effect.
Analysis of solutions for the connection between vehicle moving in land and the Hub (DVB-S2, DVB-SH and DVB-RCS):
- Developing an elliptical low profile antenna with reduced beam-width and corrugated horn
- Compatible design both with star topology networks and with regenerative satellites (Amerhis)
- Increase of the frequency adquisition window in the HUB due to the Doppler effect and other modifications in baseband (ex. modulators) to optimise the mobility conditions
- Consideration of open technologies (DVB-S and DVBS2), as well as owner technologies with turbocodes as COMTECH TPC.
The applications and services which are given from this case are different and useful for very different fields such as civil protection applications, fire detection, traffic control, emergency situations, border control, special communications for State Security Corps, etc.