Navagation processing in host based satellite positioning solution

• US 20050234713A1
• Filed: 10/10/2002
• Published: 10/20/2005
• Est. Priority Date: 10/10/2002
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Yamamoto, Clifford, Nonis, Sebastian, Bulatovic, Nikola, Pande, Ashutosh, Witanis, Stefan
• Granted Patent: US 7,546,395 B2
• Time in Patent Office: Days
• US Class Current: 704/224
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station

Abstract

Methods and systems consistent with the present invention provide a host based positioning system. The host based positioning system includes a tracker hardware interface that connects to a dedicated hardware space vehicle tracker to a host computer. The tracker hardware interface receives positioning information from the space vehicle tracker and communicates with the host computer using predefined messages. The host based positioning system includes a layered protocol approach to enable user applications on a host computer to access data from tracker hardware device.

Claims

1. A tracker hardware device, comprising:

a connection in the tracker hardware device adapted to connect the tracker hardware device to a tracker interface link;

a radio frequency interface for reception of location signals; and

a location processing circuit having a plurality of message formats that formats one message from the plurality of message formats for transmission over the tracker interface link in response to receipt of the locations signals by the radio frequency interface.

2. The tracker hardware device of claim 1, wherein each of the plurality of message formats starts with a start message sequence of 0x0A and 0xA2.

3. The tracker hardware device of claim 1, wherein each of the plurality of message formats ends with an end sequence of 0xB0 and 0xB3.

4. The tracker hardware device of claim 1, further comprising a check sum algorithm that generates a check sum for each of the messages in the plurality of messages.

5. The tracker hardware device of claim 4, wherein the check sum algorithm is

index=first byte

checkSum=0

while (index<

msgLen)

checkSum=checkSum+message[index]

checkSum=checkSum AND (2{circumflex over ( 

)}15−

1)

where message is the array of bytes to be sent and msgLen is the number of bytes in the message array to be transmitted.

6. The tracker hardware device of claim 1, wherein at lease one message in the plurality of message formats has a payload defined by at least a message ID, a bit number, a millisecond number, a carrier phase, a code offset, a carrier doppler rate, carrier Doppler frequency units, time of measurement.

7. The tracker hardware device of claim 1, wherein a received message at the location processing circuit 306 is acknowledged by transmission of an transmitted acknowledge message that has an acknowledge format defined in the plurality of message formats;

and

a plurality of messages associated with a plurality of message formats that when each is transmitted result in the tracker interface expecting to receive an associated acknowledge message, wherein failure to receive some of the associated receive acknowledge message does not impact operation of the tracker hardware device.

8. A method of communication between a tracker hardware device a computer host, comprising:

identifying a message to be formatted;

entering a start sequence into a message structure that defines the message;

entering a message identification and a message payload length in the message structure;

entering an end sequence into the message structure;

entering a length of the message derived from information in the message structure;

calculating a checksum for inclusion in the message structure based on information in the message structure; and

sending the message from the tracker hardware device via a tracker hardware link.

9. The method of claim 8, wherein entering the start sequence further includes:

placing 0xA0 and 0xA2 into the message structure for the start sequence.

10. The method of claim 8, wherein entering the end sequence further includes:

placing 0xB0 and 0xB3 into the message structure for the end sequence.

11. The method of claim 8, wherein calculating a checksum further includes:

solving an algorithm defined by;

index=first_byte

checksum=0

while (index<

msgLen)

checkSum=checkSum+message[index]

checkSum=checkSum AND (2{circumflex over ( 

)}15−

1)

Where message is the array of bytes to be sent and msgLen is the number of bytes in the message array to be transmitted.

12. The method of claim 8, further comprises:

entering measurement data into the payload of the message structure having a message identification of 0x20; and

encoding in the payload data a channel number, bit number, millisecond number, carrier phase, code offset carrier Doppler rate, carrier Doppler frequency units, and time of measurement.

13. The method of claim 8, further comprising:

waiting for receipt of an acknowledge message in response to the message sent by the tracker hardware link that may optionally be sent by the host compute.

14. The method of claim 8, wherein identifying further includes:

determining the message to be formatted is an acknowledge message that is sent in response to receipt of another message at the tracker hardware device.

15. A method of communication between a tracker hardware device a computer host, comprising:

comprising;

means for identifying a message to be formatted;

means for entering a start sequence into a message structure that defines the message;

means for entering a message identification and a message payload length in the message structure;

means for entering an end sequence into the message structure;

means for entering a length of the message derived from information in the message structure;

means for calculating a checksum for inclusion in the message structure based on information in the message structure; and

means for sending the message from the tracker hardware device via a tracker hardware link.

16. The system of claim 15, wherein means for entering the start sequence further includes:

means for placing 0xA0 and 0xA2 into the message structure for the start sequence.

17. The system of claim 15, wherein means for entering the end sequence further includes:

means for placing 0xB0 and 0xB3 into the message structure for the end sequence.

18. The system of claim 15, wherein means for calculating a checksum further includes:

means for solving an algorithm defined by;

index=first_byte

checksum=0

while (index<

msgLen)

checkSum=checkSum+message[index]

checkSum=checkSum AND (2{circumflex over ( 

)}15−

1)

Where message is the array of bytes to be sent and msgLen is the number of bytes in the message array to be transmitted.

19. The system of claim 15, further comprises:

means for entering measurement data into the payload of the message structure having a message identification of 0x20; and

means for encoding in the payload data a channel number, bit number, millisecond number, carrier phase, code offset carrier Doppler rate, carrier Doppler frequency units, and time of measurement.

20. The method of claim 15, further comprising:

means for expecting receipt of an acknowledge message in response to the message sent by the tracker hardware link that may optionally be sent by the host compute.

21. The method of claim 15, wherein identifying further includes:

means for determining the message to be formatted is an acknowledge message that is sent in response to receipt of another message at the tracker hardware device.

22. A signal bearing medium with machine readable instructions for formatting a message in a tracker hardware device, comprising:

a first set of machine readable instructions for identifying the message to be formatted;

a second set of machine readable instructions for entering a start sequence into a message structure that defines the message;

a third set of machine readable instructions for entering a message identification and a message payload length in the message structure;

a fourth set of machine readable instructions for entering an end sequence into the message structure;

a fifth set of machine readable instructions for entering a length of the message derived from information in the message structure;

a sixth set of machine readable instructions for calculating a checksum for inclusion in the message structure based on information in the message structure; and

a seventh set of machine readable instructions for sending the message from the tracker hardware via a tracker hardware link.

23. The system of claim 22, wherein entering the start sequence further includes:

an eighth set of machine readable instructions for placing 0xA0 and 0xA2 into the message structure for the start sequence.

24. The system of claim 22, wherein entering the end sequence further includes:

an eighth set of machine readable instructions for placing 0xB0 and 0xB3 into the message structure for the end sequence.

25. The system of claim 22, wherein calculating a checksum further includes:

an eighth set of machine readable instructions for solving an algorithm defined by;

index=first_byte

checksum=0

while (index<

msgLen)

checkSum=checkSum+message[index]

checkSum=checkSum AND (2{circumflex over ( 

)}15−

1)

Where message is the array of bytes to be sent and msgLen is the number of bytes in the message array to be transmitted.

26. The system of claim 22, further comprises:

an eighth set of machine readable instructions for entering measurement data into the payload of the message structure having a message identification of 0x20; and

a ninth set of machine readable instructions for encoding in the payload data a channel number, bit number, millisecond number, carrier phase, code offset carrier Doppler rate, carrier Doppler frequency units, and time of measurement.