On Sun, 29 Apr 2012 21:30:43 -0700, miso wrote:> On 4/29/2012 6:32 PM, Spehro Pefhany wrote: >> On Sun, 29 Apr 2012 17:24:36 -0700, the renowned Mark Borgerson >> <mborgerson@comcast.net> wrote: >> >>> In article<apsqp7lbsvqv9jrrleaoqpgurqg900t0e8@4ax.com>, >>> nospam@nospam9876.com says... >>>> >>>> I am looking at a project which requires a simple GPS receiver (not >>>> waas/egnos) and a low grade solid state gyro (not a "level") like the >>>> ones you get in smartphones. >>>> >>>> The build volumes will be initially a batch of 100 and later perhaps >>>> thousands, but not more than that. >>>> >>>> What would be the currently recommended GPS module or chip, and a >>>> solid state gyro component? >>>> >>>> There is a lot of stuff on the market... >>>> >>>> One requirement is reasonably low power - milliamps rather than 10s >>>> of milliamps. I have no idea if that is possible. >>> I have not yet found a GPS solution that can give 1HZ updates and draw >>> less than about 20mA. There are some that can go into a low-power >>> sleep mode and wake up on command to give a fix. However, when awake, >>> they still draw 20 to 30mA. To get the overall power down, you need a >>> fairly low duty cycle. >>>> >>>> Ideally the two items can be obtained for under $20-30. >>> >>> The low end for GPS chips that I've used is about $30 qty 1. >> >> GPS module + chip antenna should be around $17 quantity one. >> >> Cost of gyros and translational accelerometers depends a lot on their >> performance, from a few dollars up to serious dollars/euros for >> military grade stuff. >> >>>> Any pointers would be much appreciated. >>> >>> Mark Borgerson >> >> >> Best regards, >> Spehro Pefhany > > The GPSs in cars (built in units) have accelerometers. It makes the user > experience better since it can sense a turn before differential > waypoints can sense it. I don't think they have to be very good to do > that task. > > They can also do dead reckoning fairly well, but I've never been out of > GPS contact for more than a few miles. > > There is a usenet group on gps. >> sci.geo.satellite-navI'm nearly 100% sure that if you want to do credible dead reckoning you need accelerometers and gyros, not just one or the other. Gyros don't mean much when you don't know the acceleration, and accelerometers don't mean much when you don't know the vehicle direction. If there's no skidding going on, a good odometer and a steering position sensor may work better than an IMU, though. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
What is the cheapest way to get a GPS + solid state gyro?
Started by ●April 29, 2012
Reply by ●April 30, 20122012-04-30
Reply by ●April 30, 20122012-04-30
On a sunny day (Mon, 30 Apr 2012 00:07:14 -0400) it happened Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote in <bo3sp7dfd9qhdsrac7d3fp31bpn7pfrorb@4ax.com>:>GlobalSat or U-blox modules with SiRF III etc. are around $15 shipped. > >Eg. >http://www.dealextreme.com/p/eb-365-gps-engine-board-module-with-sirf-star-iii-chipset-80045?item=4Do those modules come with any sort of datasheet?
Reply by ●April 30, 20122012-04-30
On Apr 30, 8:04=A0am, Tim Wescott <t...@seemywebsite.please> wrote:> On Sun, 29 Apr 2012 21:30:43 -0700, miso wrote: > > On 4/29/2012 6:32 PM, Spehro Pefhany wrote: > >> On Sun, 29 Apr 2012 17:24:36 -0700, the renowned Mark Borgerson > >> <mborger...@comcast.net> =A0wrote: > > >>> In article<apsqp7lbsvqv9jrrleaoqpgurqg900t...@4ax.com>, > >>> nos...@nospam9876.com says... > > >>>> I am looking at a project which requires a simple GPS receiver (not > >>>> waas/egnos) and a low grade solid state gyro (not a "level") like th=e> >>>> ones you get in smartphones. > > >>>> The build volumes will be initially a batch of 100 and later perhaps > >>>> thousands, but not more than that. > > >>>> What would be the currently recommended GPS module or chip, and a > >>>> solid state gyro component? > > >>>> There is a lot of stuff on the market... > > >>>> One requirement is reasonably low power - milliamps rather than 10s > >>>> of milliamps. I have no idea if that is possible. > >>> I have not yet found a GPS solution that can give 1HZ updates and dra=w> >>> less than about 20mA. =A0There are some that can go into a low-power > >>> sleep mode and wake up on command to give a fix. =A0However, when awa=ke,> >>> they still draw 20 to 30mA. =A0To get the overall power down, you nee=d a> >>> fairly low duty cycle. > > >>>> Ideally the two items can be obtained for under $20-30. > > >>> The low end for GPS chips that I've used is about $30 qty 1. > > >> GPS module + chip antenna should be around $17 quantity one. > > >> Cost of gyros and translational accelerometers depends a lot on their > >> performance, from a few dollars up to serious dollars/euros for > >> military grade stuff. > > >>>> Any pointers would be much appreciated. > > >>> Mark Borgerson > > >> Best regards, > >> Spehro Pefhany > > > The GPSs in cars (built in units) have accelerometers. It makes the use=r> > experience better since it can sense a turn before differential > > waypoints can sense it. I don't think they have to be very good to do > > that task. > > > They can also do dead reckoning fairly well, but I've never been out of > > GPS contact for more than a few miles. > > > There is a usenet group on gps. > >> sci.geo.satellite-nav > > I'm nearly 100% sure that if you want to do credible dead reckoning you > need accelerometers and gyros, not just one or the other. =A0Gyros don't > mean much when you don't know the acceleration, and accelerometers don't > mean much when you don't know the vehicle direction.Why can't you figure out the direction with 2D accelerometers?
Reply by ●April 30, 20122012-04-30
On 4/30/2012 10:42 AM, Jan Panteltje wrote:> On a sunny day (Mon, 30 Apr 2012 00:07:14 -0400) it happened Spehro Pefhany > <speffSNIP@interlogDOTyou.knowwhat> wrote in > <bo3sp7dfd9qhdsrac7d3fp31bpn7pfrorb@4ax.com>: > > > >> GlobalSat or U-blox modules with SiRF III etc. are around $15 shipped. >> >> Eg. >> http://www.dealextreme.com/p/eb-365-gps-engine-board-module-with-sirf-star-iii-chipset-80045?item=4 > > Do those modules come with any sort of datasheet?Google found this: http://diydrones.com/profiles/blogs/cheap-gps-modules-at
Reply by ●April 30, 20122012-04-30
On Mon, 30 Apr 2012 11:09:49 -0700 (PDT), linnix <me@linnix.info-for.us> wrote:>On Apr 30, 8:04�am, Tim Wescott <t...@seemywebsite.please> wrote: >> On Sun, 29 Apr 2012 21:30:43 -0700, miso wrote: >> > On 4/29/2012 6:32 PM, Spehro Pefhany wrote: >> >> On Sun, 29 Apr 2012 17:24:36 -0700, the renowned Mark Borgerson >> >> <mborger...@comcast.net> �wrote: >> >> >>> In article<apsqp7lbsvqv9jrrleaoqpgurqg900t...@4ax.com>, >> >>> nos...@nospam9876.com says... >> >> >>>> I am looking at a project which requires a simple GPS receiver (not >> >>>> waas/egnos) and a low grade solid state gyro (not a "level") like the >> >>>> ones you get in smartphones. >> >> >>>> The build volumes will be initially a batch of 100 and later perhaps >> >>>> thousands, but not more than that. >> >> >>>> What would be the currently recommended GPS module or chip, and a >> >>>> solid state gyro component? >> >> >>>> There is a lot of stuff on the market... >> >> >>>> One requirement is reasonably low power - milliamps rather than 10s >> >>>> of milliamps. I have no idea if that is possible. >> >>> I have not yet found a GPS solution that can give 1HZ updates and draw >> >>> less than about 20mA. �There are some that can go into a low-power >> >>> sleep mode and wake up on command to give a fix. �However, when awake, >> >>> they still draw 20 to 30mA. �To get the overall power down, you need a >> >>> fairly low duty cycle. >> >> >>>> Ideally the two items can be obtained for under $20-30. >> >> >>> The low end for GPS chips that I've used is about $30 qty 1. >> >> >> GPS module + chip antenna should be around $17 quantity one. >> >> >> Cost of gyros and translational accelerometers depends a lot on their >> >> performance, from a few dollars up to serious dollars/euros for >> >> military grade stuff. >> >> >>>> Any pointers would be much appreciated. >> >> >>> Mark Borgerson >> >> >> Best regards, >> >> Spehro Pefhany >> >> > The GPSs in cars (built in units) have accelerometers. It makes the user >> > experience better since it can sense a turn before differential >> > waypoints can sense it. I don't think they have to be very good to do >> > that task. >> >> > They can also do dead reckoning fairly well, but I've never been out of >> > GPS contact for more than a few miles. >> >> > There is a usenet group on gps. >> >> sci.geo.satellite-nav >> >> I'm nearly 100% sure that if you want to do credible dead reckoning you >> need accelerometers and gyros, not just one or the other. �Gyros don't >> mean much when you don't know the acceleration, and accelerometers don't >> mean much when you don't know the vehicle direction. > >Why can't you figure out the direction with 2D accelerometers?All six degrees of freedom, three rotation and three translation, are required for a general-purpose INS. *But* if you're able to constrain the problem to, say, non-skidding/slipping car behavior then yes, two properly mounted orthogonal accelerometers could do a pretty reasonable job, modulo the usual caveats of noise and sensor drift, given an initial (or periodic) knowledge of heading and position. Better if you also include the vehicle speed in the mix, of course. -- Rich Webb Norfolk, VA
Reply by ●April 30, 20122012-04-30
On Mon, 30 Apr 2012 16:42:21 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:>On a sunny day (Mon, 30 Apr 2012 00:07:14 -0400) it happened Spehro Pefhany ><speffSNIP@interlogDOTyou.knowwhat> wrote in ><bo3sp7dfd9qhdsrac7d3fp31bpn7pfrorb@4ax.com>: > > > >>GlobalSat or U-blox modules with SiRF III etc. are around $15 shipped. >> >>Eg. >>http://www.dealextreme.com/p/eb-365-gps-engine-board-module-with-sirf-star-iii-chipset-80045?item=4 > >Do those modules come with any sort of datasheet?Check the manufacturer website, I doubt DX will give yo anything more than a padded envelope marked "gift".
Reply by ●April 30, 20122012-04-30
On Mon, 30 Apr 2012 11:09:49 -0700, linnix wrote:>> I'm nearly 100% sure that if you want to do credible dead reckoning you >> need accelerometers and gyros, not just one or the other. Gyros don't >> mean much when you don't know the acceleration, and accelerometers >> don't mean much when you don't know the vehicle direction. > > Why can't you figure out the direction with 2D accelerometers?Because without a gyro or some other angular reference you don't know what direction they're pointed. I suppose that if you were really cost-conscious you could assume no skidding and take sideways acceleration to be an indication of turning rate -- but that's a pretty tenuous connection to reality. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Reply by ●April 30, 20122012-04-30
Tim Wescott wrote:> On Sun, 29 Apr 2012 21:30:43 -0700, miso wrote: > >> On 4/29/2012 6:32 PM, Spehro Pefhany wrote: >>> On Sun, 29 Apr 2012 17:24:36 -0700, the renowned Mark Borgerson >>> <mborgerson@comcast.net> wrote: >>> >>>> In article<apsqp7lbsvqv9jrrleaoqpgurqg900t0e8@4ax.com>, >>>> nospam@nospam9876.com says... >>>>> >>>>> I am looking at a project which requires a simple GPS receiver (not >>>>> waas/egnos) and a low grade solid state gyro (not a "level") like the >>>>> ones you get in smartphones. >>>>> >>>>> The build volumes will be initially a batch of 100 and later perhaps >>>>> thousands, but not more than that. >>>>> >>>>> What would be the currently recommended GPS module or chip, and a >>>>> solid state gyro component? >>>>> >>>>> There is a lot of stuff on the market... >>>>> >>>>> One requirement is reasonably low power - milliamps rather than 10s >>>>> of milliamps. I have no idea if that is possible. >>>> I have not yet found a GPS solution that can give 1HZ updates and draw >>>> less than about 20mA. There are some that can go into a low-power >>>> sleep mode and wake up on command to give a fix. However, when awake, >>>> they still draw 20 to 30mA. To get the overall power down, you need a >>>> fairly low duty cycle. >>>>> >>>>> Ideally the two items can be obtained for under $20-30. >>>> >>>> The low end for GPS chips that I've used is about $30 qty 1. >>> >>> GPS module + chip antenna should be around $17 quantity one. >>> >>> Cost of gyros and translational accelerometers depends a lot on their >>> performance, from a few dollars up to serious dollars/euros for >>> military grade stuff. >>> >>>>> Any pointers would be much appreciated. >>>> >>>> Mark Borgerson >>> >>> >>> Best regards, >>> Spehro Pefhany >> >> The GPSs in cars (built in units) have accelerometers. It makes the user >> experience better since it can sense a turn before differential >> waypoints can sense it. I don't think they have to be very good to do >> that task. >> >> They can also do dead reckoning fairly well, but I've never been out of >> GPS contact for more than a few miles. >> >> There is a usenet group on gps. >>> sci.geo.satellite-nav > > I'm nearly 100% sure that if you want to do credible dead reckoning you > need accelerometers and gyros, not just one or the other. Gyros don't > mean much when you don't know the acceleration, and accelerometers don't > mean much when you don't know the vehicle direction. > > If there's no skidding going on, a good odometer and a steering position > sensor may work better than an IMU, though. >How about a compass module for orientation? That'll probably work OK for 2D navigation tasks between GPS fixes. Not sure what the OP needs. -- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Leap and the net will appear.
Reply by ●May 1, 20122012-05-01
On Mon, 30 Apr 2012 19:13:06 -0700, "Paul Hovnanian P.E." <paul@hovnanian.com> wrote:>Tim Wescott wrote: > >> On Sun, 29 Apr 2012 21:30:43 -0700, miso wrote: >> >>> On 4/29/2012 6:32 PM, Spehro Pefhany wrote: >>>> On Sun, 29 Apr 2012 17:24:36 -0700, the renowned Mark Borgerson >>>> <mborgerson@comcast.net> wrote: >>>> >>>>> In article<apsqp7lbsvqv9jrrleaoqpgurqg900t0e8@4ax.com>, >>>>> nospam@nospam9876.com says... >>>>>> >>>>>> I am looking at a project which requires a simple GPS receiver (not >>>>>> waas/egnos) and a low grade solid state gyro (not a "level") like the >>>>>> ones you get in smartphones. >>>>>> >>>>>> The build volumes will be initially a batch of 100 and later perhaps >>>>>> thousands, but not more than that. >>>>>> >>>>>> What would be the currently recommended GPS module or chip, and a >>>>>> solid state gyro component? >>>>>> >>>>>> There is a lot of stuff on the market... >>>>>> >>>>>> One requirement is reasonably low power - milliamps rather than 10s >>>>>> of milliamps. I have no idea if that is possible. >>>>> I have not yet found a GPS solution that can give 1HZ updates and draw >>>>> less than about 20mA. There are some that can go into a low-power >>>>> sleep mode and wake up on command to give a fix. However, when awake, >>>>> they still draw 20 to 30mA. To get the overall power down, you need a >>>>> fairly low duty cycle. >>>>>> >>>>>> Ideally the two items can be obtained for under $20-30. >>>>> >>>>> The low end for GPS chips that I've used is about $30 qty 1. >>>> >>>> GPS module + chip antenna should be around $17 quantity one. >>>> >>>> Cost of gyros and translational accelerometers depends a lot on their >>>> performance, from a few dollars up to serious dollars/euros for >>>> military grade stuff. >>>> >>>>>> Any pointers would be much appreciated. >>>>> >>>>> Mark Borgerson >>>> >>>> >>>> Best regards, >>>> Spehro Pefhany >>> >>> The GPSs in cars (built in units) have accelerometers. It makes the user >>> experience better since it can sense a turn before differential >>> waypoints can sense it. I don't think they have to be very good to do >>> that task. >>> >>> They can also do dead reckoning fairly well, but I've never been out of >>> GPS contact for more than a few miles. >>> >>> There is a usenet group on gps. >>>> sci.geo.satellite-nav >> >> I'm nearly 100% sure that if you want to do credible dead reckoning you >> need accelerometers and gyros, not just one or the other. Gyros don't >> mean much when you don't know the acceleration, and accelerometers don't >> mean much when you don't know the vehicle direction. >> >> If there's no skidding going on, a good odometer and a steering position >> sensor may work better than an IMU, though. >> > >How about a compass module for orientation? That'll probably work OK for 2D >navigation tasks between GPS fixes. Not sure what the OP needs.That's all the automotive GPS units I've seen have.
Reply by ●May 1, 20122012-05-01
On a sunny day (Mon, 30 Apr 2012 16:31:37 -0400) it happened Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote in <3kttp79uni4e3gm3e18u06ji5f2rclponv@4ax.com>:>On Mon, 30 Apr 2012 16:42:21 GMT, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: > >>On a sunny day (Mon, 30 Apr 2012 00:07:14 -0400) it happened Spehro Pefhany >><speffSNIP@interlogDOTyou.knowwhat> wrote in >><bo3sp7dfd9qhdsrac7d3fp31bpn7pfrorb@4ax.com>: >> >> >> >>>GlobalSat or U-blox modules with SiRF III etc. are around $15 shipped. >>> >>>Eg. >>>http://www.dealextreme.com/p/eb-365-gps-engine-board-module-with-sirf-star-iii-chipset-80045?item=4 >> >>Do those modules come with any sort of datasheet? > >Check the manufacturer website, I doubt DX will give yo anything more >than a padded envelope marked "gift".OK The FM modules for Hongong I have, at least had a pin connection diagram...
