초록 ▼

A system (18) includes: a) A vehicle (12) includes an attitude or angular velocity control system (38), a plurality of star trackers or star sensors (22) each having a field of view (28); b) a memory (30) having a star catalog (32), a star pair catalog (58) and a reference table (56) stored therein;

A system (18) includes: a) A vehicle (12) includes an attitude or angular velocity control system (38), a plurality of star trackers or star sensors (22) each having a field of view (28); b) a memory (30) having a star catalog (32), a star pair catalog (58) and a reference table (56) stored therein; and c) a processor (24) coupled to the attitude or angular velocity control system (38), the star trackers or star sensors (22), and the memory (30). The processor (24) determines the vehicle inertial attitude or angular velocity or sensor alignment, based, in part, on the star pair catalog (58) and reference table (56). The design of the star pair catalog (58) and reference table (56) is suitable for rapid determination of attitude or angular velocity or sensor alignment, and an efficient use of memory.

대표청구항 ▼

The invention claimed is: 1. A star pair database for use with a database having a star catalog comprising: a reference table, wherein the reference table comprises a plurality of reference table entries, each directly or indirectly specifying a bucket, said bucket defining a plurality of memory lo

The invention claimed is: 1. A star pair database for use with a database having a star catalog comprising: a reference table, wherein the reference table comprises a plurality of reference table entries, each directly or indirectly specifying a bucket, said bucket defining a plurality of memory locations in the pair catalog, for which pair catalog entries corresponding to star pairs with certain properties reside, wherein each of the plurality of reference table entries comprises a starting star pair catalog index of the associated pair catalog bucket and a number of pair records in the associated pair catalog bucket, and wherein each of the plurality of reference table entries comprises a total number of available memory locations, each capable of storing a representation of a star pair, in the associated pair catalog bucket, said reference table describing the specified locations in the star pair catalog of entries representing star pairs meeting specific criteria; and a star pair catalog containing references to pairs of stars based on the reference table and on properties of stars listed in the star database, wherein the star pair catalog comprises an ordered list of a plurality of entries, such that: each entry comprises a reference to a first star, selected from stars represented in the star catalog; each entry comprises a reference to a second star, selected from stars represented in the star catalog; an ordering of the entries is based on the value of a metric associated with each entry, where the value of the said metric may optionally be included in the entry. 2. A star pair database as recited in claim 1 wherein each of the plurality of reference table entries comprises a star pair catalog ending index of the associated pair catalog bucket. 3. A star pair database as recited in claim 1 wherein each entry in the star catalog represents a star. 4. A star pair database as recited in claim 3 wherein each entry in the star catalog comprises a value dependent on magnitude of the associated star. 5. A star pair database as recited in claim 4 wherein the selection of a star to serve as first star is based on the value, from the star catalog entry, dependent on the magnitude of the star. 6. A star pair database as recited in claim 4 wherein the selection of a star to serve as second star is based on the value, from the star catalog entry, dependent on the magnitude of the star. 7. A star pair database as recited in claim 1 wherein the selection of a pair of stars to be represented as a pair catalog entry is based on the value of the metric associated with each pair, as calculated for the pair. 8. A star pair database as recited in claim 1 wherein the metric associated with each star pair is specified to be a metric whose value is based on the angular separation between the two stars forming the pair. 9. A star pair database as recited in claim 8 wherein the metric comprises the angular separation between the two stars forming the pair. 10. A star pair database as recited in claim 1 wherein a star pair representation in the star pair catalog comprises the star catalog indices of the first and second stars forming the star pair. 11. A star pair database as recited in claim 1 wherein the star representation in the star pair catalog comprises the star catalog index of the first star and a value describing the star catalog location of the representation of the second star, with respect to the star catalog location of the representation of the first star. 12. A star pair database as recited in claim 1 wherein the value of the metric associated with a predetermined star pair is used to determine a reference table entry which specifies a "bucket", a set of potential pair catalog locations for the genertaed star pair. 13. A star pair database for use with a database having a star catalog comprising: a reference table describing the specified locations in the star pair catalog of entries representing star pairs meeting specific criteria; and a star pair catalog containing references to pairs of stars based on the reference table and on properties of stars listed in the star database, wherein the star pair catalog comprises an ordered list of a plurality of entries, such that: each entry comprises a reference to a first star. selected from stars represented in the star catalog; each entry comprises a reference to a second star, selected from stars represented in the star catalog; an ordering of the entries is based on the value of a metric associated with each entry, where the value of the said metric may optionally be included in the entry, wherein the metric associated with each star pair is specified to be a metric whose value is based on the angular separation between the two stars forming the pair, and wherein the metric comprises at least one member selected from the group consisting of: quadratic function of the angular separation between the two stars forming the pair; the cosine or sine of the angular separation between the two stars forming the pair; a polynomial function of the angular separation between the two stars forming the pair; the square of the sine of the angular separation between the two stars forming the pair; one minus the cosine of the angular separation between the two stars forming the pair; and a sin ^2 of the angular separation between the two stars forming the pair. 14. A method for determining the location of a plurality of pair catalog entries within the pair catalog comprising: determining the metric associated with each pair catalog entry whose location is desired; determining the reference table entry associated with the metric; locating the pair catalog entry desired by searching in the pair catalog bucket specified by the reference table entry.