Post by thread:GPS

Hello, I am interested in more information on GPS. Does anyone have any good links? Questions: 1) Has anyone interfaced a gps receiver with a pic before? 2) Source of low-cost gps receivers? 3) How accurate are they? 4) How do you interpret the data and calculate your location? Any information would be appreciated! -Randie ________ Randie Ohtsji / ____/ /__ ____ ____ ___ _________ email: spam_OUTrohtsjiTakeThisOuTglenayre.com / /___/ / _ \/ __ \/ __ `/ / / / __/ _ \ Glenayre R & D / /_\ / / __/ / / / /_/ / /_/ / / / __/ Vancouver, B.C. CANADA \____/_/\___/_/ /_/\__,_/\__ /_/ \___/ Phone: (604) 293-1611 x4555 ________________________/ / Fax: (604) 293-4317 /_________________________/

part 0 1025 bytes -----Original Message----- From: Randie Ohtsji [4555] [SMTP:.....rohtsjiKILLspam@spam@GLENVAN.GLENAYRE.COM] Sent: Tuesday, December 09, 1997 2:34 PM To: PICLISTKILLspamMITVMA.MIT.EDU Subject: gps Hello, I am interested in more information on GPS. Does anyone have any good links? Questions: 1) Has anyone interfaced a gps receiver with a pic before? 2) Source of low-cost gps receivers? 3) How accurate are they? 4) How do you interpret the data and calculate your location? Any information would be appreciated! -Randie ________ Randie Ohtsji / ____/ /__ ____ ____ ___ _________ email: .....rohtsjiKILLspam.....glenayre.com / /___/ / _ \/ __ \/ __ `/ / / / __/ _ \ Glenayre R & D / /_\ / / __/ / / / /_/ / /_/ / / / __/ Vancouver, B.C. CANADA \____/_/\___/_/ /_/\__,_/\__ /_/ \___/ Phone: (604) 293-1611 x4555 ________________________/ / Fax: (604) 293-4317 /_________________________/

Randie, I'm working on that now, check out http://www.leadtek.com.tw for a good low cost GPS receiver that uses the SiRF Technologies chipset. The output is a NEMA 0183, basically RS-232 at 4800 baud (5V too) accuracy is 100m with out the differential antenna... Cost is about $150 for 1 unit to around $85 for 10K units location is by position from a series of 24 satellites that orbit the earth, for more detailed info than that go to Amazon.com and order "Understanding GPS principles and applications" by Elliott D. Kaplan (recommended for engineers only) Hope this helps Jason {Original Message removed}

part 0 1148 bytes Try: http://www.trimble.com/ (Trimble is one of the big end-user and OEMs) http://www.garmin.com/ (Garmin is also big into small GPS units <pun intended>). ---------- From: Randie Ohtsji [4555] Sent: Tuesday, December 09, 1997 2:33 PM To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU Subject: gps Hello, I am interested in more information on GPS. Does anyone have any good links? Questions: 1) Has anyone interfaced a gps receiver with a pic before? 2) Source of low-cost gps receivers? 3) How accurate are they? 4) How do you interpret the data and calculate your location? Any information would be appreciated! -Randie ________ Randie Ohtsji / ____/ /__ ____ ____ ___ _________ email: rohtsjispam_OUTglenayre.com / /___/ / _ \/ __ \/ __ `/ / / / __/ _ \ Glenayre R & D / /_\ / / __/ / / / /_/ / /_/ / / / __/ Vancouver, B.C. CANADA \____/_/\___/_/ /_/\__,_/\__ /_/ \___/ Phone: (604) 293-1611 x4555 ________________________/ / Fax: (604) 293-4317 /_________________________/

At 11:33 AM 12/9/97 -0800, you wrote: {Quote hidden}>Hello, > >I am interested in more information on GPS. Does anyone have any good >links? > >Questions: > > 1) Has anyone interfaced a gps receiver with a pic before? > 2) Source of low-cost gps receivers? > 3) How accurate are they? > 4) How do you interpret the data and calculate your location? > >Any information would be appreciated! > >-Randie > ________ > Randie Ohtsji / ____/ /__ ____ ____ ___ _________ > email: @spam@rohtsjiKILLspamglenayre.com / /___/ / _ \/ __ \/ __ `/ / / / __/ _ \ > Glenayre R & D / /_\ / / __/ / / / /_/ / /_/ / / / __/ > Vancouver, B.C. CANADA \____/_/\___/_/ /_/\__,_/\__ /_/ \___/ > Phone: (604) 293-1611 x4555 ________________________/ / > Fax: (604) 293-4317 /_________________________/ > Hi Randie, Have a look at: http://www.navcen.uscg.mil/gps/reports/sigspec/gpssps1.pdf and http://www.navcen.uscg.mil/gps/reports/sigspec/gpsspsa.pdf These are the official GPS signal specifications from the U.S. Coast Guard. I'm not sure if this is what you are looking for (i.e. it won't tell you how to interface to a GPS receiver) but this has most if not all of the technical specs needed to design a GPS receiver or to figure our the error in a GPS reading due to certain circumstances. Good Luck, Sean +--------------------------------+ | Sean Breheny | | Amateur Radio Callsign: KA3YXM | | Electrical Engineering Student | +--------------------------------+ http://www.people.cornell.edu/pages/shb7 KILLspamshb7KILLspamcornell.edu

Randie Ohtsji [4555] wrote: > Hello, > I am interested in more information on GPS. Does anyone have any good links? Try: http://www.inmet.com/~pwt/gps_gen.htm This page gives a huge number of links. Look out for the pages that describe "NMEA sentences" which explain the format of the RS232 data that comes out of a GPS device. NMEA is "National Maritime Engineering Association" and they have laid down the standards for decades; not just GPS, but Loran, Decca, etc. Newsgroup: sci.geo.satellite-nav gives extremely up-to-date info about commercially available GPS devices and software (but not tonight, it seems, because my newsfeed has gone down again). You can ask really stupid questions and nobody minds. In fact they don't always notice. Example (I read this recently): "Why don't marine GPS receivers give out the altitude information sentences like the aircraft GPS receivers do?" Answer: "Boats generally operate at sea level...." Robin Lovelock's Home Page: http://www.gpss.co.uk Here, you can download huge amounts of his GPSS software, especially maps of just about anywhere in the world. The system is meant for use in vehicles - with the complete setup you talk to it and it answers (obviously, you can't operate a keyboard and drive as well). For example you say to it, "McDonalds", and it replies, "2 miles ahead, first right". Robin is a very kind man and you can ask him stupid questions, as I did. His GPSS software suddenly stopped working for me. I had written a small program, in Basic, on an old PC, that emulated a GPS receiver. It "flew" from London to Edinburgh at any speed I set, and sent the data out the RS232 at 4800 baud in NMEA sentence format, and into the RS232 on the PC running the GPSS software. I can recommend this as a way of getting to grips with NMEA data. You can keep clear of difficult maths by making gross assumptions about the Latitude and Longitude of the source and destination; find out how miles there are in a degree (Lat and Long) in your part of the world, and then become a flat-earthist (for this project only), and it's simple geometry. The problem: it turned out Robin had at last correctly implemented the checksum that follows an NMEA sentence (a simple little 1-byte thing, no problem for a PIC). Some older GPS devices didn't bother with the checksum, but GPSS ignores these sentences now. And quite right too, since they might contain serious errors. John Blackburn, South London UK.

In a message dated 97-12-09 16:42:28 EST, you write: << I am interested in more information on GPS. Does anyone have any good links? >> About a year ago, I looked at gps stuff. I found that Trimble has two nice little books they are willing to give you that discuss GPS and Differential GPS....great introductory stuff. Several companies had small recievers (small is relative...not small enough for my application at the time) and the cheapest solution I found was a chip set from Rockwell that was approx $50US, if I remember correctly. After you get the signals received and coorellated, you still need reasonable power to calculate position and do anything with it. I do not think that the PIC is the right horse for this plow. If you want more details, e-mail me privately and I will dig out my file and try to answer specific questions, but these times are-a-changin' and you will likely find more useful info via a search with your favorite www engine. If you find anything very small (less than one inch square) or very cheap ($30 or less at 100K volume) please let me know, I may be able to dig up my old client and convince them to re-open the project. Mark A. Corio Rochester MicroSystems, Inc. 200 Buell Road, Suite 9 Rochester, NY 14624 Tel: 716-328-5850 Fax: 716-328-1144 http://www.frontiernet.net/~rmi/ ****** Designing Electronics for Research and Industry ******

Hi We use GPS recievers in our data loggers....the 1Hz signal they provide helps lock the loggers as it is more accurate in the long term than a crystal (though not in the short term cos of the jitter the military put in) We paid NZ$300 (about$200US) for a Trimble reciever. These recievers (and I guess most) also put out an rs232 signal every second of about 20 words, containing stuff like the hour,minute,second,velocity,and position I think. Basically your manual will give the details. This can be read by anything that can read rs232. The iHz pulse is ttl level, and I'm told the rising edge(but not the falling) is accurate to 500nS Hope this helps Tim On Tue, 9 Dec 1997, John Shreffler wrote: > Try http://www.ashtech.com You can get bare boards for $98 > > {Original Message removed}

This dude doesn't like his pages displayed outside of his frames. From his homepage, select schaltungen then computer then "GPS - Empfdnger Teil 1" It requires a a hybrid integrated circuit MS1 from the American manufacturer SiRF Technology http://www.sirf.com/ which has a microcontroller and uses a receiver from Swiss company 5-BLOX AG, (smallest GPS in the world?) --- James Newton spamBeGonejamesnewtonspamBeGonegeocities.com 1-619-652-0593 http://techref.massmind.org NEW! FINALLY A REAL NAME! Members can add private/public comments/pages ($0 TANSTAAFL web hosting) {Original Message removed}