Avionics

Avionics

The aviation community utilises GNSS systems extensively: as en-route navigation aids for commercial and general aviation communities; for enhanced safety in take-off and landing operations; to increase system capacity through more effective planning systems and a variety of military avionics applications. The full opportunity for GNSS in the aviation and avionics area is just being realised, future air traffic management (ATM) systems that will maintain high levels of safety, while reducing delays and increasing airway capacity are being developed and introduced.

Chronos and GPS-World supply many products suitable for aviation applications, from GNSS receivers and receiver systems; Arinc standard antennas and micro-antennas for UAV systems and many other products used in the applications below.

ADS-B

Systems such as Automatic Dependent Surveillance-broadcast (ADS-B) utilise GNSS signals for position determination with Multi-Constellation receiver systems being deployed to mitigate single system risk. ADS-B is intended to increase safety, capacity and efficiency:

Improved visual acquisition especially for general aviation under visual flight rules (VFR); Reduced spacing on final approach and improved services in non-RADAR airspace are just some of the benefits of ADS-B.

SBAS

Satellite Based Augmentation System (SBAS) technology has been used within aviation receivers for some time to improve the accuracy, availability, reliability and integrity of a navigation solution. The multiple systems now deployed globally such as WAAS, EGNOS, MSAS and QZSS, deliver significant improvements in these areas for commercial, general and military aviation users. FAA testing for WAAS shows that it is able to achieve a Category I precision approach accuracy of 1m lateral and 4m vertically, in fact the tests showed that 1m and 1.5m accuracy levels were obtained. (National Satellite Test Bed (NSTB), WAAS PAN Report (July 2006)) Some systems also feature Ground Based Augmentation Systems (GBAS) or Local Area Augmentation System (LAAS) technology for localised accuracy/integrity improvements.

New Signals

GPS L5 signal deployment will aid aviation systems as it has been designed for safety-of-life applications and presents improved performance by higher power transmissions, enhanced signal structure, wider bandwidth and an operating frequency in the ARNS band. Future GALILEO services include a Safety-of-Life service which is planned to broadcast data such as integrity warning messages and also operates in the ARNS frequency band.

DO178B

In the USA, the FAA applies the RTCA document DO-178B as the document to provide guidance to determine if software in avionics systems will perform safely and reliably, in an airborne environment. DO-178B details Design Assurance Levels (DAL) which are determined from the safety assessment process and hazard analysis of a system.

The levels denote the effect of failure of a system on the aircraft, crew, and passengers and are given the letters A (Catastrophic) to E (No effect). DO-178B is one aspect of a safety assessment process but important for all systems where software (embedded/non-embedded) is used.

Timing

GNSS systems are also used to provide accurate time and frequency distribution and synchronisation for on board avionics systems and for ground based infrastructure. Effective timing systems ensure data/traffic flow and security can be maintained.

Hangar GNSS Repeater Systems for maintenance and operations

Chronos and its partners have supplied many airlines globally with the facility to improve their maintenance efficiency and reduce costs. This is enabled by the use of GPS repeater systems installed to repeat the live signals within the GPS denied environment of a hangar. Chronos offer system design and installation services to ensure correct installation of repeater system to prevent unintentional interference with direct path GNSS signals.

• Hangar systems for airline maintenance and repair facilities
• Reduced maintenance time and costs by enabling trouble shooting, repair, and testing of aircraft systems within maintenance facilities
• Fixed or portable systems for maximum flexibility

Marine

Marine

The very first satellite navigation systems were designed for marine use, by the military of the time, and now the marine industry is one of the largest users of GNSS technology and many of the specific applications developed for the marine industry have become ubiquitous across all application sectors.

Ocean going navigation, track control, coastal navigation, DGPS and other Aids to Navigation (AtoN), Hydrography, Dredging and dynamic positioning are all operations that require precise positioning and have driven the development of GNSS technology through the years.

GNSS Receivers and Infrastructure

Multi-constellation, multi-frequency receivers are used in the most demanding marine applications such as automated docking and marine construction and they demand the highest quality products to ensure the safety of life and equipment.

Chronos represents manufacturers of high quality GNSS receivers, proven in many marine applications. Systems such as container tracking systems, GPS compasses, DGPS receivers and OEM products for system integration can all be supplied to customers.

Chronos has been supplying infrastructure products to the marine industry for many years. Specialised antenna systems and GNSS distribution products are amongst the products that Chronos has supplied to both the civilian marine industry and naval military organisations. Many of the Chronos staff have direct experience of the needs of maritime customers.

Dredging

Dredging is about construction: Dikes, land reclamation, artificial island construction as well as the commonly known waterway maintenance and construction are significant elements of the dredging industry. Each of these functions require the use of a range of specialised support tools such as suction or cutter dredgers, lateral offloading boats, barges and crane-equipped pontoons. For all of these areas, high quality and productivity are major requirements but costs must also be taken into account.

This cost trade-off moves the dredging industry to use leading-edge precise positioning techniques in order to ensure the highest possible return on investment. Precision demanding dredging activities require the centimetre accuracy provided by real-time kinematic GNSS techniques. The techniques are commonly used for on-line tide compensation and gauge evolution during loading. Other functions are the need for precise positioning and timing for underwater acoustic survey systems which can graphically represent underwater environments such as for sub-surface maintenance or extraction. Septentrio receivers are ideally suited to this function, and companies such as Dredging International use their products. Chronos are the Septentrio UK representative.

GPS Compass

Chronos supply the GPS Compass systems from Hemisphere GPS. These products provide accurate heading and positioning, superior performance including heave pitch and roll output on some products. The rugged enclosure combines Hemisphere GPS’ Crescent Vector II OEM board and two multipath-resistant antennas for accuracy, portability and simple installation. The half-meter length smart antenna mounts easily to a flat surface or pole. The stability and maintenance-free design of the V101 replaces traditional gyrocompasses at a fraction of the cost.