1. A resource sharing apparatus, for enabling at least one peripheral apparatus to be shared by a plurality of personal computers, the resource sharing apparatus comprising:
an application specific integrated circuit (ASIC), comprising:
a plurality of hubs, each of the hubs having a host port (B port), and a plurality of peripheral ports (A port), wherein the hubs are one-to-one coupled to the personal computers via the host ports;
a plurality of device controllers, coupled to the peripheral ports, wherein the device controllers are one-to-one coupled to the hubs for stimulating the peripheral apparatus;
a bus, coupled to the device controllers;
a host controller, coupled to the bus, for stimulating peripheral apparatus related functions of an operation system (OS) or a basis inputoutput operation system (BIOS) in the personal computers, and communicating with the device controllers via the bus;
a root hub, comprising a host port and a plurality of peripheral ports, wherein the host port of the root hub is coupled to the host controller, and the peripheral apparatus is coupled to one of the peripheral ports of the root hub; and
a central processing unit, coupled to the bus for controlling the operation of the ASIC.
2. The resource sharing apparatus according to claim 1, wherein the hubs, the device controllers, and the host controller have interfaces of universal serial bus specifications.
3. The resource sharing apparatus according to claim 2, wherein the peripheral apparatus comprises a printer.
4. The resource sharing apparatus according to claim 2, wherein the peripheral apparatus comprises a keyboard.
5. The resource sharing apparatus according to claim 2, wherein the peripheral apparatus comprises a mouse.
6. The resource sharing apparatus according to claim 1, wherein the resource sharing apparatus is used for enabling a first peripheral apparatus and a second peripheral apparatus to be shared by a plurality of personal computers, the first peripheral apparatus is coupled to one of the peripheral ports of the root hub, and the resource sharing apparatus comprises:
a first switch, coupled to one of the peripheral ports of each hub; and
a second switch, coupled to the first switch, the root hub, and the second peripheral apparatus, wherein the second peripheral apparatus is coupled to the root hub or one of the hubs by the first switch and the second switch according to a controlling signal from the central processing unit.
7. The resource sharing apparatus according to claim 6, wherein the hubs, the device controllers, and the host controller have interfaces of universal serial bus specifications.
8. The resource sharing apparatus according to claim 7, wherein the first peripheral apparatus is a keyboard, and the second peripheral apparatus is a mouse.
9. The resource sharing apparatus according to claim 1, wherein the resource sharing apparatus is used for enabling a first peripheral apparatus and a second peripheral apparatus to be shared by a plurality of personal computers, the first peripheral apparatus is coupled to one of the peripheral ports of the root hub, and the resource sharing apparatus comprises:
a switch, coupled to the second peripheral apparatus and one of the peripheral ports of each hub, wherein the second peripheral apparatus is coupled to one of the hubs by the switch according to a controlling signal from the central processing unit.
10. The resource sharing apparatus according to claim 9, wherein the hubs, the device controllers, and the host controller have interfaces of universal serial bus specifications.
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 position calculating method comprising:
determining a positioning satellite used for position calculation on the basis of at least reliability of satellite orbits in a prediction target period corresponding to a position calculation point, the reliability of satellite orbits being set in long-term predicted orbit data in which satellite orbits of positioning satellites and reliability of the satellite orbits are associated for each prediction target period; and
calculating a position on the basis of a positioning signal received from the determined positioning satellite.
2. The position calculating method according to claim 1, further comprising extracting a predetermined number of positioning satellites in order from one having highest reliability of a satellite orbit and determining a satellite used for the position calculation.
3. The position calculating method according to claim 1, further comprising deciding positioning satellites having equivalent reliability of the satellite orbit in the prediction target period corresponding to the position calculation point, wherein
the determining includes determining, taking into account reliability of a satellite orbit in a prediction target period before or after the prediction target period corresponding to the position calculation point, whether the positioning satellites having equivalent reliability of the satellite orbit should be used for the position calculation.
4. The position calculating method according to claim 1, further comprising:
deciding a reception environment for the positioning signal; and
determining a satellite used for the position calculation on the basis of the decided reception environment.
5. The position calculating method according to claim 4, further comprising:
variably setting, according to the decided reception environment, at least a determination target period including the prediction target period corresponding to the position calculation point in the prediction target period included in the long-term predicted orbit data; and
determining a satellite used for the position calculation on the basis of reliability in the determination target period.
6. A position calculating device comprising:
a determining unit that determines a positioning satellite used for position calculation on the basis of at least reliability of satellite orbits in a prediction target period corresponding to a position calculation point, the reliability of satellite orbits being set in long-term predicted orbit data in which satellite orbits of positioning satellites and reliability of the satellite orbits are associated for each prediction target period; and
a position calculating unit that calculates a position on the basis of a positioning signal received from the determined positioning satellite.