초록 ▼

To reduce error introduced by the local oscillator in the velocity calculations, the receiver has two “tracking channels”and a microcomputer. With numbers required to, simultaneously, lock each of the “tracking channels”each to a respective satellite signal, the microcomputer employs a differential

To reduce error introduced by the local oscillator in the velocity calculations, the receiver has two “tracking channels”and a microcomputer. With numbers required to, simultaneously, lock each of the “tracking channels”each to a respective satellite signal, the microcomputer employs a differential doppler technique to calculate the receiver velocity. The microcomputer calculates a number which represents the difference between the apparent doppler frequency shift of the carrier signal which is transmitted by the first “tracking channel”satellite and which is measured over a specific time period and the apparent doppler frequency shift of the carrier signal which is transmitted by the second “tracking channel”satellite and which is measured over substantially the same time period.

대표청구항 ▼

A GPS satellite receiver for computing the velocity of the receiver from information obtained from the apparent doppler frequency shift of four carrier signals each transmitted by a respective one of four satellites, the receiver comprising in combination: means for receiving each of the carrier sig

A GPS satellite receiver for computing the velocity of the receiver from information obtained from the apparent doppler frequency shift of four carrier signals each transmitted by a respective one of four satellites, the receiver comprising in combination: means for receiving each of the carrier signals; means for computing, a first number which represents the difference between, the apparent doppler frequency shift of the received carrier signal which is transmitted by a first one of the satellites and which is measured over a first predetermined time period, and the apparent doppler frequency shift of the received carrier signal which is transmitted by one of said satellites other than said first satellite and which is measured over a predetermined time period at least a portion of which includes at least a portion of said first predetermined time period, a second number which represents the difference between, the apparent doppler frequency shift of the received carrier signal which is transmitted by a second one of said satellites and which is measured over a second predetermined time period, and the apparent doppler frequency shift of the received carrier signal which is transmitted by one of said satellites other than said second satellite and which is measured over a predetermined time period at least a portion of which includes at least a portion of said second predetermined time period, a third number which represents the difference between, the apparent doppler frequency shift of the received carrier signal which is transmitted by a third one of said satellites and which is measured over a third predetermined time period, and the apparent doppler frequency shift of the received carrier signal which is transmitted by one of said satellites other than said third satellite and which is measured over a predetermined time period at least a portion of which includes at least a portion of said third predetermined time period; and means for computing the velocity of the receiver from said first, said second, and said third numbers.