1. An electrode for measuring electrical activity of tissue, the electrode comprising:
a sensing electrode having an elongate electrode body forming a partial hollow half cylindrical section having a proximal end, a distal end, and a curved inner surface configured to partially enclose a curved outer surface of the tissue and with:
i. a penetrating end at the distal end for insertion into the tissue to sense electrical activity of the tissue, and
ii. a base end at the proximal end that is coupled to an electrical connection wire for communicating the sensed electrical activity away from the sensing electrode; and
a fixation element that penetrates through an electrode opening in the elongate electrode body into the tissue partially enclosed by the curved inner surface of the partial hollow half cylindrical section of the electrode body to hold the penetrating end of the sensing electrode in position in the tissue.
2. An electrode according to claim 1, wherein the fixation element includes a secondary sensing electrode that also senses electrical activity of the tissue.
3. An electrode according to claim 2, wherein the sensing electrode and the secondary sensing electrode form a bipolar electrode sensing arrangement.
4. An electrode according to claim 1, further comprising:
an electrical insulation layer where the fixation element penetrates the electrode body for electrically isolating the fixation element from the electrode body.
5. An electrode according to claim 4, wherein the insulation layer is ceramic, sapphire, A2O3, TiO2, or glass.
6. An electrode according to claim 4, wherein the insulation layer has a thickness between 10 \u03bcm and 30 \u03bcm.
7. An electrode according to claim 1, including an insulation layer covering at least a portion of the sensing electrode or the fixation element.
8. An electrode according to claim 7, wherein the insulation layer is silicone or polyurethane elastomer.
9. An electrode according to claim 1, wherein the fixation element is formed of electrically insulating material and the sensing electrode acts as a monopolar sensing arrangement.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A mobile unit’s position measurement apparatus comprising:
a reception portion that receives signals from a plurality of satellites;
an observation data selection portion
that calculates a plurality of estimated error values that correspond respectively to a plurality of pieces of observation data obtained by observing the signals received by the reception portion,
that generates groups, each of which includes estimated error values corresponding to at least a predetermined number of satellites, and
then extracts, from the estimated error value groups generated, estimated error value groups in which a difference between a maximum value and a minimum value of the estimated error values included is less than a predetermined value, and
that consequently selects pieces of observation data provided by the signals from the satellites that correspond to the estimated error values that are included in an estimated error value group whose standard deviation of the estimated error values is smallest among the estimated error value groups extracted; and
a positioning computation portion that performs a positioning computation based on the pieces of observation data selected by the observation data selection portion.
2. The mobile unit’s position measurement apparatus according to claim 1, wherein the observation data is at least one of a pseudo-distance between the plurality of satellites and the mobile unit’s position measurement apparatus, an amount of change in the Doppler frequency of a signal that the reception portion receives, and an integrated value of the amount of change in the Doppler frequency.
3. The mobile unit’s position measurement apparatus according to claim 2, further comprising a positionvelocity estimation portion that estimates a position and a velocity of the mobile unit, wherein the observation data selection portion calculates the estimated error value based on the pseudo-distance, and the position of the mobile unit.
4. The mobile unit’s position measurement apparatus according to claim 3, wherein, the observation data selection portion calculates the estimated error value based on the amount of change in the Doppler frequency, and the velocity of the mobile unit.
5. The mobile unit’s position measurement apparatus according to claim 2, wherein the observation data selection portion calculates the estimated error value based on the integrated value of the amount of change in the Doppler frequency, and the position of the mobile unit.
6. The mobile unit’s position measurement apparatus according to claim 1, wherein
each of the generated groups includes at least a predetermined number of estimated error values selected from the plurality of estimated error values calculated, and
the groups are generated based on combinations of the at least the predetermined number of estimated error values.
7. The mobile unit’s position measurement apparatus according to claim 6, wherein the predetermined number estimated error values is commensurate with the predetermined number of satellites.
8. The mobile unit’s position measurement apparatus according to claim 6, wherein the groups are generated based on all possible combinations of the at least the predetermined number of estimated error values.
9. The mobile unit’s position measurement apparatus according to claim 1, wherein the generated groups includes x generated groups, where x=nCr+nCr+1+nCr+2 . . . nCn, n is a total number of the plurality of estimated error values, and r is the predetermined number of satellites.
10. The mobile unit’s position measurement apparatus according to claim 1, wherein the generated groups include groups of each possible combination of at least a predetermined number of the plurality of estimated error values.
11. The mobile unit’s position measurement apparatus according to claim 10, wherein the predetermined number of the plurality of estimated error values is the predetermined number of satellites.
12. The mobile unit’s position measurement apparatus according to claim 11, wherein the predetermined number of satellites is a number of satellites needed for the positioning computation.
13. A mobile unit’s position measurement method comprising:
calculating a plurality of estimated error values that correspond respectively to a plurality of pieces of observation data that are obtained by observing signals transmitted from a plurality of satellites;
generating groups, each of which includes estimated error values corresponding to at least a predetermined number of satellites; then
extracting, from the estimated error value groups generated, estimated error value groups in which a difference between a maximum value and a minimum value of the estimated error values included is less than a predetermined value; and then
selecting pieces of observation data provided by the signals from the satellites that correspond to the estimated error values that are included in an estimated error value group whose standard deviation of the estimated error values is smallest among the estimated error value groups extracted; and
performing a positioning computation based on the at least one or all of the pieces of observation data selected.