초록 ▼

Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Ka

Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.

대표청구항 ▼

Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Ka

Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions. ne or more interlock slides movably mounted on the housing and a faceplate for restricting unauthorized access to the slides. The number of interlock slides is one fewer than the number of circuit breakers so that the slides can be positioned to provide access to only one of the switches of the circuit breakers, while the remaining switches of the circuit breakers cannot be accessed. Each of the switches of the circuit breakers can be individually accessed without the slides extending beyond the periphery of the housing. n weight, a cationic photoinitiator; b. applying the permanent plating resist on the substrate; c. photoimaging the permanent plating resist to form apertures in the permanent plating resist wherein said apertures are aligned with portions of the circuitry of the substrate; and, d. electrolessly plating metal into the apertures in the permanent plating resist, wherein the metal is selectively plated onto the circuitry of the substrate. 8. A method of claim 7, further comprising the step of: e. attaching components to features of substrate, wherein the permanent plating resist remains on the substrate during steps d and e. 9. The method of claim 7, wherein the metal is gold. 10. The method of claim 7, wherein the permanent plating resist has: from 20 to 40% of phenoxy polyol resin having a molecular weight of from about 60,000 to 90,000; from about 25 to 30% of an epoxidized multifunctional bisphenol A formaldehyde novolac resin having a molecular weight of from about 5,000 to 7,000; from about 35 to 50%, of a diglycidyl ether of bisphenol A having a molecular weight of from about 1,000 to 1,700; and from about 0.1 to 15 parts by weight of the total resin weight, a cationic photoinitiator; wherein the metal is copper. 11. The method of claim 10, wherein the phenoxy polyol resin has an epoxide value of about 0.03 equivalents per kg, a weight per epoxide of about 37,000 and a glass transition temperature of about 98° C.; the epoxidized multifunctional bisphenol A formaldehyde novolac resin has an epoxide value of about 4.7 equivalents per kilogram, as weight per epoxide of about 215 and a melting point of about 82° C.; and the diglycidyl ether a bisphenol A has an epoxide value of about 1.5 equivalents per kilogram, a weight per epoxide of about 675 and a melting point of about 97° C. 12. A circuitized structure comprising: a. a circuitized substrate; b. a first layer of metal features disposed on the substrate; c. a cured, photoimaged, permanent plating resist having photoimaged apertures disposed therein 1 said permanent plating resist disposed on the substrate, wherein the permanent plating resist comprises an epoxy resin system comprising: i. from about 10 to 80% of phenoxy polyol resin which is the condensation product of epichlorohydrin and bisphenol A, having a molecular weight of from about 40,000 to 130,000; ii. from about 20 to 90% of an epoxidized multifunctional bisphenol A formaldehyde novolac resin having a molecular weight of from about 4,000 to 10,000; iii. from 0 to 50% of a diglycidyl ether of bisphenol A having a molecular weight of from about 600 to 2,500; and iv. less than 15% of a cationic photoinitiator; and less than about 8% solvent; f. electrolessly plated gold, disposed on portions of the metal features, and said gold disposed in the apertures; g. circuitry disposed on, and adherent to the permanent plating resist, the circuitry on the permanent plating resist being electrically connected to the circuitry disposed on the substrate; and h. electrical components disposed atop the permanent plating resist and in electrical contact with the electrolessly plated gold features. 13. The circuitized structure of claim 12, wherein there is: from 20 to 40% of phenoxy polyol resin having a molecular weight of from about 60,000 to 90,000; from about 25 to 30% of an epoxidized multifunctional bisphenol A formaldehyde novolac resin having a molecular weight of from about 5,000 ,to 7,000; from about 35 to 50%, of a brominated diglycidyl ether of bisphenol A having a molecular weight of from about 1,000 to 1,700. 14. The circuit board of claim 13, wherein: the phenoxy polyol resin has an epoxide value of about 0.03 equivalents per kg, a weight per epoxide of about 37,000 and a glass transition temperature of about 98° C.; the epoxidized multifunctional bisphenol A formaldehyde novolac resin has an epoxide value of about 4.7 equivalents per kilogram, as weight p