I recently attended a lecture on Optomechanical accelometry for inertial navigation, from NIST (National Institute for Science and Technology in the US). It's very clever, probably an advance in the art. They are at the noise floor for such devices. One fundamental limitation they mentioned was "laser noise" causing a 1/f noise peak at low frequencies. This rang a bell - didn't Phil Hobbs invent a way to cancel laser relative intensity noise (RIN)? Yes. And it seems to be a perfect place to use this method, so I told the speakers of US patent 5,134,276 and the companion article in the literature. They had heard of Phil and have his book on electro optics. It would be dead simple to cancel RIN in their application, so I bet they will do it. The application: .<https://www.nist.gov/people/feng-zhou> Look at the first two papers listed under "Publications", "Broadband thermo mechanically limited sensing with an Optomechanical accelerometer" and "Electrooptic frequency combs for rapid interrogation in cavity optomechanics". More papers are likely to emerge. Joe Gwinn
Optomechanical accelometry for inertial navigation
Started by ●September 17, 2021
Reply by ●September 17, 20212021-09-17
Joe Gwinn <joegwinn@comcast.net> wrote in news:r86akg5d0o1mi0pgjpuje4r03o5rk0oons@4ax.com:> I recently attended a lecture on Optomechanical accelometry for > inertial navigation, from NIST (National Institute for Science and > Technology in the US). > > It's very clever, probably an advance in the art. They are at the > noise floor for such devices. One fundamental limitation they > mentioned was "laser noise" causing a 1/f noise peak at low > frequencies. This rang a bell - didn't Phil Hobbs invent a way to > cancel laser relative intensity noise (RIN)? > > Yes. And it seems to be a perfect place to use this method, so I > told the speakers of US patent 5,134,276 and the companion article > in the literature. They had heard of Phil and have his book on > electro optics. It would be dead simple to cancel RIN in their > application, so I bet they will do it. > > The application: > > .<https://www.nist.gov/people/feng-zhou> > > Look at the first two papers listed under "Publications", > "Broadband thermo mechanically limited sensing with an > Optomechanical accelerometer" and "Electrooptic frequency combs > for rapid interrogation in cavity optomechanics". > > More papers are likely to emerge. > > Joe Gwinn >The IRU (Inertial Reference Unit) we used was housed in an 8 inch cube made by GE. It was $50k. We sold it for $100k. They are some of the most accurate devices of the type known. <https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.mce-asic.co.uk% 2Fmilitary%2Fsystems%2Favionics%2Fdocs%2FIRU-land- navigation.pdf&psig=AOvVaw0LADLrwmBNYV_0fmJcaU4q&ust=1632008640585000 &source=images&cd=vfe&ved=0CAkQjRxqFwoTCPi2vIyYh_MCFQAAAAAdAAAAABAD>
Reply by ●September 17, 20212021-09-17
Joe Gwinn wrote:> I recently attended a lecture on Optomechanical accelometry for > inertial navigation, from NIST (National Institute for Science and > Technology in the US). > > It's very clever, probably an advance in the art. They are at the > noise floor for such devices. One fundamental limitation they > mentioned was "laser noise" causing a 1/f noise peak at low > frequencies. This rang a bell - didn't Phil Hobbs invent a way to > cancel laser relative intensity noise (RIN)? > > Yes. And it seems to be a perfect place to use this method, so I told > the speakers of US patent 5,134,276 and the companion article in the > literature. They had heard of Phil and have his book on electro > optics. It would be dead simple to cancel RIN in their application, > so I bet they will do it. > > The application: > > .<https://www.nist.gov/people/feng-zhou> > > Look at the first two papers listed under "Publications", "Broadband > thermo mechanically limited sensing with an Optomechanical > accelerometer" and "Electrooptic frequency combs for rapid > interrogation in cavity optomechanics". > > More papers are likely to emerge. > > Joe Gwinn >One of my best gizmos ever. Thanks! Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●September 19, 20212021-09-19
On Fri, 17 Sep 2021 23:45:26 -0000 (UTC), DecadentLinuxUserNumeroUno@decadence.org wrote:>Joe Gwinn <joegwinn@comcast.net> wrote in >news:r86akg5d0o1mi0pgjpuje4r03o5rk0oons@4ax.com: > >> I recently attended a lecture on Optomechanical accelometry for >> inertial navigation, from NIST (National Institute for Science and >> Technology in the US). >> >> It's very clever, probably an advance in the art. They are at the >> noise floor for such devices. One fundamental limitation they >> mentioned was "laser noise" causing a 1/f noise peak at low >> frequencies. This rang a bell - didn't Phil Hobbs invent a way to >> cancel laser relative intensity noise (RIN)? >> >> Yes. And it seems to be a perfect place to use this method, so I >> told the speakers of US patent 5,134,276 and the companion article >> in the literature. They had heard of Phil and have his book on >> electro optics. It would be dead simple to cancel RIN in their >> application, so I bet they will do it. >> >> The application: >> >> .<https://www.nist.gov/people/feng-zhou> >> >> Look at the first two papers listed under "Publications", >> "Broadband thermo mechanically limited sensing with an >> Optomechanical accelerometer" and "Electrooptic frequency combs >> for rapid interrogation in cavity optomechanics". >> >> More papers are likely to emerge. >> >> Joe Gwinn >> > > The IRU (Inertial Reference Unit) we used was housed in an 8 inch >cube made by GE. It was $50k. We sold it for $100k. They are some >of the most accurate devices of the type known. > >.<https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.mce-asic.co.uk%2Fmilitary%2Fsystems%2Favionics%2Fdocs%2FIRU-land-navigation.pdf&psig=AOvVaw0LADLrwmBNYV_0fmJcaU4q&ust=1632008640585000&source=images&cd=vfe&ved=0CAkQjRxqFwoTCPi2vIyYh_MCFQAAAAAdAAAAABAD>Interesting. How does it compare with the FOG-based IMUs from iXblue? I'm guessing that canceling the RIN noise will reduce the bias error, which typically dominates errors important in dead-reckoning navigation. Joe Gwinn
Reply by ●September 19, 20212021-09-19
Joe Gwinn <joegwinn@comcast.net> wrote in news:mo0fkg1ept3d0au1apg2pssbghagsslgbk@4ax.com:> On Fri, 17 Sep 2021 23:45:26 -0000 (UTC), > DecadentLinuxUserNumeroUno@decadence.org wrote: > >>Joe Gwinn <joegwinn@comcast.net> wrote in >>news:r86akg5d0o1mi0pgjpuje4r03o5rk0oons@4ax.com: >> >>> I recently attended a lecture on Optomechanical accelometry for >>> inertial navigation, from NIST (National Institute for Science >>> and Technology in the US). >>> >>> It's very clever, probably an advance in the art. They are at >>> the noise floor for such devices. One fundamental limitation >>> they mentioned was "laser noise" causing a 1/f noise peak at low >>> frequencies. This rang a bell - didn't Phil Hobbs invent a way >>> to cancel laser relative intensity noise (RIN)? >>> >>> Yes. And it seems to be a perfect place to use this method, so >>> I told the speakers of US patent 5,134,276 and the companion >>> article in the literature. They had heard of Phil and have his >>> book on electro optics. It would be dead simple to cancel RIN >>> in their application, so I bet they will do it. >>> >>> The application: >>> >>> .<https://www.nist.gov/people/feng-zhou> >>> >>> Look at the first two papers listed under "Publications", >>> "Broadband thermo mechanically limited sensing with an >>> Optomechanical accelerometer" and "Electrooptic frequency combs >>> for rapid interrogation in cavity optomechanics". >>> >>> More papers are likely to emerge. >>> >>> Joe Gwinn >>> >> >> The IRU (Inertial Reference Unit) we used was housed in an 8 >> inch >>cube made by GE. It was $50k. We sold it for $100k. They are >>some of the most accurate devices of the type known. >> >>.<https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.mce-asic.co. >>uk%2Fmilitary%2Fsystems%2Favionics%2Fdocs%2FIRU-land-navigation.pdf >>&psig=AOvVaw0LADLrwmBNYV_0fmJcaU4q&ust=1632008640585000&source=imag >>es&cd=vfe&ved=0CAkQjRxqFwoTCPi2vIyYh_MCFQAAAAAdAAAAABAD> > > Interesting. How does it compare with the FOG-based IMUs from > iXblue? I'm guessing that canceling the RIN noise will reduce the > bias error, which typically dominates errors important in > dead-reckoning navigation. > > Joe Gwinn >I do not know that much about their internals. I do know (well think)they were very long fiber optic coils in three axis, IIRC. I seem to remember seeing something in one of the of hard copy tech publications I used to read, like NASA Tech Briefs or such. That was a long time ago. I am sure they have come a long way since on accuracy improvement, etc. You know... all the stuff that counts in such an instrument.
