초록 ▼

A global positioning system (GPS) receiver has first circuitry for receiving and processing pseudorandom sequences transmitted by a number of GPS satellites. The first circuitry is configured to perform conventional correlation operations on the received pseudorandom sequences to determine pseudoran

A global positioning system (GPS) receiver has first circuitry for receiving and processing pseudorandom sequences transmitted by a number of GPS satellites. The first circuitry is configured to perform conventional correlation operations on the received pseudorandom sequences to determine pseudoranges from the GPS receiver to the GPS satellites. The GPS receiver also includes second circuitry coupled to the first circuitry. The second circuitry is configured to receive and process the pseudorandom sequences during blockage conditions. The second circuitry processes the pseudorandom sequences by digitizing and storing a predetermined record length of the received sequences and then performing fast convolution operations on the stored data to determine the pseudoranges. The GPS receiver may have a common circuitry for receiving GPS signals from in view satellites and downconverting the RF frequency of the received GPS signals to an intermediate frequency (IF). The IF signals are split into two signal paths; a first of which provides the conventional correlation processing to calculate the pseudoranges. During blockage conditions, the IF signal is passed to the second signal path wherein the IF signals are digitized and stored in memory and later processed using the fast convolution operations to provide the pseudoranges. Alternative arrangements for the two signal paths include separate downconverters or shared digitizers. One embodiment provides both signal paths on a single integrated circuit with shared circuitry executing computer readable instructions to perform GPS signal processing appropriate to the reception conditions.

대표청구항 ▼

A global positioning system (GPS) receiver has first circuitry for receiving and processing pseudorandom sequences transmitted by a number of GPS satellites. The first circuitry is configured to perform conventional correlation operations on the received pseudorandom sequences to determine pseudoran

A global positioning system (GPS) receiver has first circuitry for receiving and processing pseudorandom sequences transmitted by a number of GPS satellites. The first circuitry is configured to perform conventional correlation operations on the received pseudorandom sequences to determine pseudoranges from the GPS receiver to the GPS satellites. The GPS receiver also includes second circuitry coupled to the first circuitry. The second circuitry is configured to receive and process the pseudorandom sequences during blockage conditions. The second circuitry processes the pseudorandom sequences by digitizing and storing a predetermined record length of the received sequences and then performing fast convolution operations on the stored data to determine the pseudoranges. The GPS receiver may have a common circuitry for receiving GPS signals from in view satellites and downconverting the RF frequency of the received GPS signals to an intermediate frequency (IF). The IF signals are split into two signal paths; a first of which provides the conventional correlation processing to calculate the pseudoranges. During blockage conditions, the IF signal is passed to the second signal path wherein the IF signals are digitized and stored in memory and later processed using the fast convolution operations to provide the pseudoranges. Alternative arrangements for the two signal paths include separate downconverters or shared digitizers. One embodiment provides both signal paths on a single integrated circuit with shared circuitry executing computer readable instructions to perform GPS signal processing appropriate to the reception conditions. 4, 20010200, Khavakh et al., 701/209; US-6262026, 20010300, Nimura et al., 701/211; US-6212472, 20010400, Nonaka et al., 701/208; US-6259987, 20010700, Ceylan et al., 701/200; US-6374180, 20020400, Slominski et al., 701/208 tes an abnormal side; and calculating intersections which are necessary for machining. 3. The three-dimensional machining method according to claim 1, wherein inputting said functions in the plurality of forms includes inputting rational functions and analytical functions. 4. The three-dimensional machining method according to claim 1, wherein the algebraic method determines solutions if all functions are rational functions and the analytic method determines solutions if at least one of the functions is not a rational function. 5. The three-dimensional machining method according to claim 3, wherein the algebraic method determines solutions if all functions are rational functions and the analytic method determines solutions if at least one of the functions is not a rational function. 6. The program according to claim 2, wherein receiving said functions in the plurality of forms includes receiving rational functions and analytical functions. 7. The program according to claim 2, wherein the algebraic method determines solutions if all functions are rational functions and the analytic method determines solutions if at least one of the functions is not a rational function. 8. The program according to claim 6, wherein the algebraic method determines solutions if all functions are rational functions and the analytic method determines solutions if at least one of the functions is not a rational function. 9. A three-dimensional machining method for machining a workpiece in mutually rectangular directions along an x-axis, a y-axis and a z-axis with a programmed computer, the method comprising the steps of: inputting functions in a plurality of forms which express a plurality of curved surfaces and curves, said functions including rational functions and analytical functions; determining whether solutions of the functions can be figured out by one of an algebraic method and an analytic method; calculating the solutions by one of the algebraic method and the analytic method depending on the determination and defining the plurality of curved surfaces by a set of functions with respect to paramete