Altek Corporation

Hung-Sheng Chen

A method for obtaining a precise sampling frequency of a global positioning system (GPS) is applied in a GPS receiver. First, a radio frequency (RF) module of the GPS receiver is used to receive a satellite signal from at least one satellite. Then, a plurality of code delays of the satellite signal is calculated at a fixed time interval, and time differences between all adjacent two code delays among all the obtained code delays are calculated to obtain a plurality of time differences. Next, a mean value of all the obtained time differences is calculated. At last, a ratio between 1000 times of the mean value and the fixed time interval is calculated to obtain an error value, and the error is added to a standard sampling frequency of the RF module to obtain a new sampling frequency.

Method for obtaining precise sampling frequency of global positioning system (GPS)

A method for calculating current position coordinate and a method for calculating a pseudo range are applied to a global positioning system (GPS) receiver. A position coordinate of the GPS receiver at the positioning time point is calculated through an average pseudo range between the GPS receiver and each satellite at a positioning time point. With regard to calculating the average pseudo range between the GPS receiver and each satellite, for each satellite, original pseudo ranges are obtained through calculating a pseudo range between the satellite and the GPS receiver at each millisecond (ms) in a time range including the positioning time point, and then the average pseudo range between the satellite and the GPS receiver at the positioning time point is obtained through calculating an average value of the obtained original pseudo ranges between the GPS receiver and the satellite.

Method for calculating current position coordinate and method for calculating pseudo range

A satellite information operation method of a GPS device includes following steps. An antenna module is provided, so as to receive a satellite signal. A signal processing circuit is provided, so as to perform an analog-to-digital conversion on the satellite signal and obtain a plurality of first digital data. A memory with a comparison table stored therein is provided, and the comparison table records corresponding relations between a plurality of second digital data and a plurality of return values. A CPU is provided, which groups the first digital data in sequence by using a bit number of any second digital data in the comparison table, obtains each of the second digital data consistent with each group of first digital data through comparison, and looks up a corresponding return value according to each of the second digital data obtained through comparison to continue the operation according to the obtained return value.

Satellite information operation method of GPS device

An electronic device for decoding a navigation data by using a phase angle variation and a method thereof are described, which includes the following steps. A phase angle difference between the first phase angle of the first navigation data and the second phase angle of the second navigation data from a satellite signal is calculated. When the phase angle difference is greater than 90 degrees, the first navigation data and the second navigation data are determined to have opposite signs. The second navigation data according to the first navigation data and the result is determined. Therefore, each data is interpreted through directly comparing whether the phase angle difference with the previous data is greater than 90 degrees or not, so that the correct rate in decoding the navigation data is increased.

Electronic device for decoding navigation data by using phase angle variation and method thereof

A method for searching satellites includes obtaining a position information, obtaining a time information, calculating a regional range according to the position information, finding out numbers of target satellites corresponding to the time information and within the regional range from ephemeris data in an ephemeris database, searching the target satellites corresponding to the numbers, and receiving the satellite signals from each searched target satellite. In an electronic device capable of searching satellites, an operation interface is used to output the position information, and a calculation unit is used to calculate the regional range according to the received position information. A look-up unit is electrically connected to the ephemeris database, and used to find out the numbers of the target satellites corresponding to time information and within the regional range from the ephemeris data.

Electronic device and method for searching satellites

A method for obtaining a precise intermediate frequency for a global positioning system (GPS) is applied in a GPS receiver having a radio frequency (RF) module. Using a satellite signal received by the RF module, ephemeris data of a satellite is completely obtained, and present coordinate of the GPS receiver is calculated. First coordinate of the satellite at first time point and second coordinate of the satellite at second time point are calculated using the ephemeris data. Then, traveling speed of the satellite and projection value of the traveling speed on position vector from the first coordinate to the present coordinate are calculated using the first time point, the first coordinate, the second time point, and the second coordinate. Finally, the precise intermediate frequency is calculated using the signal frequency, a carrier frequency of the satellite, the projection value, and velocity of light.

Method for obtaining precise intermediate frequency of global positioning system (GPS)

A method for calculating current position coordinate is applied to a global positioning system (GPS) receiver. When positioning at a current time point, the GPS receiver directly calculates a code delay and a carrier frequency of each satellite and position coordinate of the GPS receiver at a current positioning time point by utilizing an ephemeris data of each satellite and position coordinate of the GPS receiver at a last positioning time point, thereby greatly lowering an operation amount, so as to reduce the power consumption.

Method for calculating current position coordinate

A method for obtaining correct phase inversion points in a signal of global positioning system (GPS) includes the following steps. A satellite signal from one of a plurality of satellites is received continuously. A plurality of phase inversion points in the received satellite signal is interpreted. Each time difference between each two adjacent phase inversion points among the plurality of phase inversion points is calculated. It is determined whether each of the time differences is an integral multiple of 20 milliseconds. A data is retrieved every 20 milliseconds from the satellite signal by using a first phase inversion point in the plurality of phase inversion points as a starting point when each of the time differences is an integral multiple of 20 milliseconds. By finding out a plurality of correct phase inversion points in the satellite signal, the positioning speed is increased, and thus a positioning time required is reduced.

Method for obtaining correct phase inversion points in signal of GPS

A method for obtaining a precise tracking frequency of a global positioning system (GPS) signal is described, which includes the following steps. A plurality of data from a satellite is continuously received. Each data has a tracking frequency. A plurality of phase differences of the received data is calculated. A phase difference average of the obtained phase differences is calculated. A frequency difference is calculated by the calculated phase difference average and a constant frequency parameter. A new tracking frequency is calculated by the frequency difference and a tracking frequency of the last data among the plurality of received data. A next data is received by the calculated new tracking frequency. A new tracking frequency is obtained by repeatedly calculating the average phase differences of the plurality of data received from the satellite and a constant frequency parameter, so as to obtain the most precise tracking frequency.

Method for obtaining precise tracking frequency of GPS signal

A method for tracking a satellite signal by a GPS includes the following steps. Data is continuously received from one of satellites by using tracking frequencies updated one by one based on an average phase difference of received data. Phase inversion points in the plurality of received data are interpreted. A time difference between each two adjacent phase inversion points among the phase inversion points is calculated. It is determined whether each time difference is an integral multiple of 20 ms. When each time difference is an integral multiple of 20 ms, 1-bit data is retrieved for every 20 ms from the satellite signal by taking a first phase inversion point among the plurality of phase inversion points as a starting point. Thus, a positioning speed is increased and a required positioning time is reduced by finding out a precise tracking frequency and a correct phase inversion point.

Growing community of inventors

Taipei County, Taiwan

Hung-Sheng Chen