# US 4,393,707 A · Fluidic angular rate sensor employing ionized gas

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- Number: US 4,393,707 A
- Document ID: US4393707A
- Status: Granted
- Kind: A
- Application number: 06/308,321
- Filed: 1981-10-02
- Granted: 1983-07-19
- Earliest claimed: 1981-10-02
- Assignees: United Technologies Corporation
- Inventors: Carl M. Ferrar
- Web page: https://patentgrep.com/patent/US4393707A

## CPC

- G01C 19/58: Turn-sensitive devices without moving masses
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)

## Abstract

A fluidic angular rate sensor employs an ionized stream of gas 104, the deflection of which is detected by an amplifier 130 connected to a pair of collection electrodes 122 and 124, motive power for the gas stream 104 being provided by momentum transfer from ions in a corona discharge.

## Claims

### Claim 1

A fluidic angular rate sensor comprising:
means for generating and directing a gas stream along an axis passing through a quantity of substantially stationary gas;
means for creating ions over a predetermined region of said gas stream and said stationary gas;
a center electrode positioned on said axis;
ion-collecting means comprising at least two ion-collecting electrodes for collecting ions from said gas stream at least two positions displaced symmetrically from said axis by a first predetermined transverse distance in a first plane passing through said axis, to form first and second ion currents;
a pair of compensating electrodes disposed symmetrically about said axis at a second predetermined transverse distance greater than said first predetermined transverse distance in said first plane, said pair of compensating electrodes being biased with respect to said center electrode by a bias amount such that ions are attracted from the vicinity of said ion-collecting electrodes toward said compensating electrodes, the amount of said bias being such that ion flow from said ion-collecting electrodes to said compensating electrodes is substantially equal to ion flow from said center electrode to said ion-collecting electrodes, whereby current flow common to both said ion currents is reduced;
means for combining said first and second ion currents to form a signal representative of the difference between said ion currents.

### Claim 2 (depends on 1)

A fluidic angular rate sensor according to claim 1, further comprising a pair of retarding electrodes, disposed intermediate said pair of collecting electrodes and said pair of compensating electrodes and having substantially the same electrical potential as said center electrode; in which sensor said collecting electrodes extend along a first portion of said axis having a first ion-source end disposed toward said means for creating ions and said reflecting electrodes extend along a second portion of said axis having a second ion-source end, which second ion source end is further along said axis from said ion source than said first ion-source end, whereby ions passing said first ion-source end are reflected back toward said first ion-source end by said reflecting electrodes.