Abstract: Method and apparatus for synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, such as a GPS or GLONASS signal, that consists of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point, such as the preferred signal time of arrival. A first autocorrelation function ACI(&tgr;) is generated between the preferred, interference-free signal and a reference signal that replicates the preferred signal, as a function of the time shift &tgr; between the two signals. A second autocorrelation signal ACM(&tgr;) is measured between the reference signal and the incoming signal.

Abstract: A tilt predictor incorporated into a total station to predict the degree of tilt of the rotational alidade portion of a total station corresponding to the rotational orientation of the rotational alidade portion. In one embodiment, the present invention defines the plane of rotation for the rotational alidade portion with the rotational alidade portion disposed in a first rotational orientation. The rotational alidade portion is then rotated to the desired rotational orientation. This embodiment then predicts the degree of tilt of the rotational alidade portion at the desired rotational orientation.

Abstract: A tilt predictor incorporated into a total station to predict the degree of tilt of the rotational alidade portion of a total station corresponding to the rotational orientation of the rotational alidade portion. In one embodiment, the present invention defines the plane of rotation for the rotational alidade portion with the rotational alidade portion disposed in a first rotational orientation. The rotational alidade portion is then rotated to the desired rotational orientation. This embodiment then predicts the degree of tilt of the rotational alidade portion at the desired rotational orientation.

Abstract: An audible signal generator incorporated into a total station to audibly indicate to the user the rotational orientation of the total station, and a method for using the audible indication to perform the tilt sensor calibration. In one embodiment, the present invention indicates to the user of the total station when the tilt sensor has been calibrated with the total station in a first rotational orientation. This embodiment then audibly indicates to the user when the rotational alidade portion of the total station has been rotated to a second rotational orientation. This embodiment then audibly indicates to the user when the tilt sensor has been calibrated with the total station in the second rotational orientation.

Abstract: An electronic distance meter comprises an integrated circuit from a GPS navigation receiver having a local pseudo-random number code generator for code demodulation that is connected to modulate either a polychromatic or a monochromatic light source. An optical system focuses the light on a distant target with an unknown range. Reflections from the distant target are focused on a light detector that produces a phase-delayed copy of the original pseudo-random number code. The time-of-flight to and back from the distant target is a function of the distance. The GPS receiver integrated circuit computes the range based on the code-phase delay to a precision better than one centimeter. The position of a remote target can be triangulated from several electronic distance meters each having known positions, e.g., determined by included GPS navigation receivers.

Abstract: The present invention provides a method and apparatus for expediently determining the azimuthal orientation of a total station. In one embodiment, the present invention is comprised of a total station having a vertical axis. The total station also includes a rotational alidade portion adapted to rotate about the vertical axis, and an electronic distance measuring portion. The present invention also includes a satellite-based position determining system antenna coupled to the total station. In the present invention, the satellite-based position determining system antenna is offset from the vertical axis. That is, in the present invention, the satellite-based position determining system antenna is not disposed coincident with the vertical axis of the total station.