AUAV is happy to announce the development and release of our new redundant 8 channel digital spread spectrum radio control system.

This system was designed to utilize a conventional R.C. transmitter control box with the RF module removed (we recommend the Futaba 9C) this allows the end user to capitalize on the programming and mixing features of the Futaba 9C.

The system is connected to the Futaba 9C by plugging the data cable in to the trainer port on the back of the Futaba 9C

This new system uses a combination of the 900 MHz and 2.4 GHz frequencies found in the unlicensed Industrial, Scientific and Medical (ISM) Bands.

There are versions of the system available for use on licensed or Military bands as well.

Why this system was developed.

Over the many years of operating remotely controlled vehicles it has become evident that we can reliably control what takes place on board the vehicles this is due to the major improvements in electronics. What we have not been able to control is what takes place outside of the vehicles in the RF spectrum. With the single RF channel control systems that are currently employed to operate remotely controlled vehicles we have been at the mercy of unexpected or unknown radio interference.

With a single RF channel system, should an offending radio signal appear at the receiver along with the control signal the single RF channel receiver can not tell the difference between the interfering signal and the control signal and in most cases this will induce a loss of control of the vehicle.

The Redundant 8 RC Channel Digital Spread-Spectrum Radio Control System (will be referred to as the system) was designed to use a combination of the 900 MHz and 2.4 GHz frequencies found in the unlicensed Industrial, Scientific and Medical (ISM) radio Bands. Licensed bands are also available with proof of license.

The major advantage of this design is in its redundancy. By utilizing two separate frequency bands (900 MHz and 2.4 GHz) and digital spread-spectrum technology, the system is virtually immune interference from outside sources that conventional single RF channel radio control systems are subject to.

The following is a brief description of how this unique design concept works.

The transmit side.

This system was designed to utilize a conventional radio control transmitter box with the RF module removed. This allows the end user to capitalize on the programming and mixing features of the host radio control transmitter (we recommend the Futaba 9C).

The system is connected to the RC transmitter via a data cable plugged into the trainer port. The other end of the data cable is connected to the system's data encoder unit where the control commands are processed and converted into a format that can be transmitted over the digital spread spectrum (DSS) RF links. The data is then sent to the two digital spread transmitters where it is sent over the air as RF energy.

The receive side:

The RF energy is then received by the two digital spread-spectrum receivers. The receivers convert the data back to the same format as that of the RC transmitter.

It is then sent to the decoder unit where it is converted to servo control data and sent to the respective servos.

The magic of the system is in the encoding and decoding of the data and the DSS technology. In the event that the primary over-the-air link suffers from interference on one of the many RF channels that it's operating on, it would lose very little of the servos positional data due the fast hopping sequence of the DSS technology.

In the event that the primary over-the-air link should experience interference on two or more consecutive RF channels, the decoder unit will detect this and switch over to the backup link. This is very unlikely do to the randomness of the hopping sequence. The backup link can be on a completely different set of RF channels within the same band, or on a completely different band entirely. This automatically utilizes the redundant backup link to maintain control of the vehicle. Once the offending interference is terminated, the link that was the primary becomes the backup. The system will switch back to the original link in the event that the new primary link should experience interference or a total failure.

In the event of a failure of both the primary and backup links, the system will go into a

preprogrammed "fail-safe mode". The remote vehicle will stay in the fail-safe mode until one of the links recovers. It will then resume operating on either single link as long as the link is good.

One of the major design requirements for this system was that during the initial system boot up, if one of the RF links was not operating the system would go into the standby mode. In the stand by mode the Futaba 9C will not control of any of the servos, this is to prevent the vehicle operator from launching the vehicle unaware that there is only one operational link and no backup link.

The most important feature of this system is that everything is taken care of behind the scenes. The operator doesn't need to take any action. The system detects the problem and automatically corrects for it without interruption in control of the vehicle.