a
unit of the United States Power Squadron
for Sail and Power Boating
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a
unit of the United States Power Squadron
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Safety NotesGPS UPDATE - Global Positioning System, On May 1, 2000 the Selective Availability (SA) mode was disabled for the general public. The SA mode was used to degrade the signal to civilian receivers. With SA disabled, the previous 100 meters accuracy was increased to 10 meters. Additionally accuracy can still be obtained by using Differential GPS (DGPS) (at 3 meters) or even better accuracy with the Wide Area Augmentation System (WAAS) (at 1.5 meters).PFD UPDATE - Personal Floatation Devices (PFD's), The U.S. Coast Guard has approved automatically inflatable PFD's for the SOSpenders brand. The PFD is automatically inflated by a CO2 cartridge upon immersion in water. Prior approved PFD's were manually operated only. For further information visit http://www.sospenders.com CHAPMAN SAFETY AWARD - ResQ Disk, Dr. Sytko and his company were presented with the Chapman Safety Award for the ResQ Disk. This device is an improved alternative to throwing a line attached floatable device to a person in the water. The improvements consist of a device (like a frizbee) that can be thrown a further distance with a greater amount of line more accurately and greater buoyancy. For further information call Save A Life at 1(877) 222-4343 or send mail to ResQDISC@aol.com .The device is available for about $25.00. NJ LAW UPDATE - Personal Floatation Devices (PFD's), law effective in New Jersey on January 1, 1999. PFD's are now MANDATORY for children 12 years old and under while aboard ANY vessel, WHETHER OR NOT UNDERWAY. NAVIGATION ALERT - GPS Epoch Rollover Alert, beginning on August 22, 1999, GPS units manufactured prior to 1997 may become useless when the week counter rolls over and starts from zero. The 20 year epoch calendar system used for GPS started on January 6, 1980 with week zero (0). The total number of weeks counted are 1024 (0 to 1023) and rollover occurs in the summer on August 22, 1999 at 0000 UTC (midnight) . GPS receiver software may think that they are back in the year 1980 unless special coded to handle that situation. If the GPS receiver searches the wrong 20 year window, then the correct date, aquisition of the satellites and a usable fix may be impossible. If the GPS is constantly on during the rollover period, then it may adjust itself correctly. All major manufacturers have indicated that this problem is well understood and recently manufactured receivers can handle the rollover date. Older units may need to do a manual cold start. This is done by setting your known position and current time and date and letting the GPS download the current almanac from the satellites by initating a cold start aquisition, from the selection menu, if possible. As a side issue, there is also the year 2000 problem that may occur when the GPS is communicating with another instrument (radar, plotter, etc) over NMEA-0183 interface. Both instruments need to interpret the year 2000 correctly when transmitted as a 2 digit number (i.e 00 for 2000). As always, never rely on only one source of positioning information.Contact your manufacturer for complete information and possible software (FLASH ROM) updates. Have your model, hardware serial number and software version ready. [ list of GPS manufacturers] [Furuno] [Garmin]
[JRC] [Magellan]
[Motorola] [Lowrance]
[Raytheon]
[SiTex] [Standard]
[Trimble] [cool
GPS site]
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