GPS World - May 2008 - (Page 31)

Vehicle Integration | AVIONICS & TRANSPORTATION slot and one of the 25 frequency bands. If the transceiver detects traffic there, it will randomly select another time slice and frequency, and try again. Since power and space are not major design factors in the V-unit, it contains a single-board computer (SBC) that hosts the a real-time operating system (RTOS) on which the PAS application software runs. For the prototype, we chose a rugged SBC module containing a 300 MHz, 2.0 VDC processor. Although equipped with a board to connect to the most popular vehicle bus (known as CAN), which often includes information on the state of the transmission, speed, and accelerometer measurements, in the prototype discrete input/output lines connected to the transmission and turn signal are used to aid orientation of the warning zone. Finally, the SBC controls the driver alert that consists of audible warnings (tone and verbal) and LEDs that indicate the direction of the ped. The configuration of this driver interface is important to provide a driver timely information for safe evasive action. We designed human factors testing to evaluate our initial approach to the interface and determine the final configuration for the prototype. A test of the specific configuration of the driver alerts was conducted at the FHWA Turner Fairbank Highway Research Center in Washington D.C. The driver interface tested consisted of a string of LEDs across the dashboard that were triggered individually to indicate the direction to the ped; a central four-light cluster indicated the state of the system and current warning level; and recorded tones and messages provided audible alerts. In general, the subjects expressed strong support for the PAS mission and the general approach. Based on the results and their comments, we made the following design The Gold Standard in Communica on & Posi oning Reach the summit of communications and GNSS. The journey to market-readiness demands skill, determina on, and partners you can count on. No wonder Paciﬁc Crest is the leading provider of radio solu ons in the geoma cs industry. Today, Paciﬁc Crest supports product developers with a wider range of communica on and posi oning technologies, including Trimble GNSS receiver modules. So, reach for the summit. And do it with conﬁdence. PAS Field Testing A successful PAS prototype must demonstrate four capabilities: An effective interface with the driver that clearly communicates timely warnings; A robust communications link between the V & P units that can accommodate multiple peds; Differential GPS (DGPS) performance that provides accurate relative position and velocity vectors; Accurate predictions of the relative position and velocity vectors up to 8 seconds in the future in order to determine the probability of collision and required warning, if any. Human Factors Test. The human factors issues in the design of the driver alert are complex. The system must unambiguously convey the urgency of the alert and provide directional information to aid in evasive maneuvers, while not contributing to driver distraction and confusion, nor being so annoying that the owner disables it, nor so bland that it is ignored. www.gpsworld.com THE BEST IN OEM GNSS NOW AVAILABLE THROUGH PACIFIC CREST The Trimble BD960 GNSS receiver module is a mul -channel, mul -frequency GNSS receiver, in a compact Eurocard form factor. Trimble' s leading cen meter-level posi oning technology is now available in an easy-to-integrate module. Now you can harness Trimble-precision in modernized GPS L2C and L5, plus GLONASS L1/L2 signals and OmniSTAR support. Visit paciﬁccrest.com/BD960/ to ﬁnd out more about Trimble OEM GNSS solu ons. 1.800.795.1001 or 1.408.653.2070 © Copyright 2008, Paciﬁc Crest Corpora on. All rights reserved. All other trademarks are the property of their respec ve owners. May 2008 | GPS World 31 http://ccrest.com/BD960/ http://ccrest.com/BD960/ http://www.gpsworld.com

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GPS World - May 2008 Contents Out in Front Letters to the Editor Expert Advice GPS III Contract Award Now a Reality? Near-Space Location Boost RTK Crops Up in Precision Ag Safety Afoot 50+ Leaders to Watch Making a Difference with GPS Product Showcase Advertisers Index & Company Directory Marketplace Classifieds Seen & Heard

GPS World - May 2008

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