Abstract: A pseudolite translator apparatus and method for using a pseudolite translator. In one embodiment, a pseudolite translator includes a receiver which is adapted to receive position information having a first frequency. The position information is transmitted from a pseudolite. In the present embodiment, the first frequency at which the position information is transmitted from the pseudolite is an unlicensed frequency. A frequency converting processor of the translator converts the position information having the first unlicensed frequency to position information having a second frequency. The translator also contains an output unit which is coupled to the frequency converting processor. The output unit is adapted to communicate the position information having the second frequency to a position determining device.

Abstract: An apparatus for securing a GPS data collector to a range pole includes an elongated base plate. The base plate has sidewalls, retaining wings, at least one first tab resiliently mounted perpendicularly to the base plate, at least one bottom support lip extending normally upward from the bottom of the base plate, and at least one second tab mounted to the bottom support lip and extending upward parallel to the base plate. Each of the tabs are adapted to engage a corresponding slot in the lower end of a data collector and the wings constrain the head end of a data collector unit.

Abstract: An apparatus and method for providing map information of varying resolution to a navigation device. In one embodiment, a position determining system is attached to a navigation device. The position determining system generates position information, such as location, of the navigation device. The position information is transmitted to a base station containing map information. Map information related to, for example, the location of the navigation device is then transmitted from the base station to the navigation device. The map information is displayed on a display of the navigation device. Therefore, the base station only transmits map information related to the position information of the navigation device.

Abstract: An antenna structure has a radiating element and a ground plane. The ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region. At least the peripheral region of the ground plane has a sheet resistivity that increases as radial distance from the central region increases. Though physically small, the ground plane simulates an infinite ground plane, and the antenna structure reduces multipath signals caused by reflection from the earth.

Abstract: An adjustment mechanism for a telescope of a theodolite. The mechanism includes a worm gear that is coupled to a friction gear of the theodolite. The friction gear is coupled to the telescope so that any rotation of the gear will induce a corresponding movement of the scope. The worm gear is coupled to a linear screw and an outer sleeve. The linear screw has a shaft that can push the worm gear and rotate the friction gear to provide a fine movement of the telescope. The linear screw also has a stop that engages an arm of the sleeve. Continued rotation of the linear screw rotates the engaged sleeve and the worm gear to provide a coarse movement of the telescope. The linear screw is connected to a knob which can be rotated by an operator. The operator can induce a coarse movement of the telescope by turning the linear screw so that the stop engages the sleeve.

Abstract: A GPS/radio antenna for receiving a GPS satellite signal and a DGPS radio signal. The GPS/radio antenna includes a GPS antenna using a microstrip antenna element for receiving the GPS signal having GPS location determination information, a radio antenna for receiving a DGPS radio signal in the FM broadcast frequency range having DGPS corrections, an enclosure, and a cable. The GPS/radio antenna may be included in a GPS/DGPS receiver system also including a receiver unit with an FM DGPS receiver for demodulating the DGPS radio signal and providing DGPS corrections, and a differential-ready GPS receiver for providing a differentially-corrected GPS location.

Abstract: The system and method of allowing the civilian GPS receivers to utilize the satellite transmitted P(Y) code signal without requiring the detailed P(Y) code to be revealed inside the receiver are disclosed. This is done by using the W code generator inside the civilian receiver, by integrating the W code signal across the W period, and by delaying the integrated signal to protect against the possible spoofing attack. The generator of the integrated and delayed W code signal is placed inside the tamper-proof container.

Abstract: Several fixed-location pseudolites transmit coordinates of their respective positions to a local area navigation receiver. The respective position and range information to each pseudolite are used to compute the position of the receiver. The pseudolites transmit on frequencies exempt from licensing requirements at power levels under one watt and use spread spectrum communication and pseudo random number codes similar to the global positioning system operated by the United States Government.

Abstract: A method for enhancing the accuracy of location coordinates and/or clock bias computed for a mobile user station that is part of a Satellite Positioning System (SATPS), such as GPS or GLONASS. A data processing station is provided with pseudorange corrections PRC(t;j;ref) for an SATPS reference station for each of M SATPS satellites (j=1, . . . , M; M.gtoreq.3) and with uncorrected location fix coordinates x'(t.sub.f), y'(t.sub.f)', z'(t.sub.f)' and/or b'(t.sub.f) for the mobile station for a selected location fix time t.sub.f. A matrix equation H(t.sub.f ;mob).DELTA.W(t.sub.f ;mob)=PRC(t.sub.f ;ref) relates a matrix .DELTA.W of location fix coordinate corrections for the mobile station to a matrix PRC(t;ref) of the pseudorange correction values, where H(t.sub.f ;mob) is an M.times.N matrix (M.ltoreq.N; N=3 or 4) with known entries computed from mobile station data. An inverse or pseudo-inverse matrix H(t.sub.f ;mob).sup.(-1) is formed satisfying the relation H(t.sub.f ;mob).sup.(-1) H(t.sub.

Abstract: An improved navigation satellite receiver with a super heterodyne receiver channel configured to provide a first local oscillator frequency between L1 and L2 such that the down converted intermediate frequencies of L1 and L2 can be processed by the same intermediate frequency stages and a second mixer stage. A radio frequency (RF) selector switch is provided to select between inputting L1 and L2 to the first mixer. The RF switch is controlled by a digital signal processor (DSP) that also provides automatic gain control (AGC) to an intermediate frequency amplifier. Histories and expected levels of AGC for each of L1 and L2 are maintained by the DSP. The RF switch is briefly toggled over to select one of L1 or L2, while tracking a satellite on the other carrier frequency, just long enough to sample the AGC level needed. If the level is too high, given the histories and expectations for such levels, the sampled carrier frequency is assumed to be jammed, and a high risk for switching over.

Abstract: A radio system that determines its location and configures itself according to the radio communication regulations of the location. The radio system includes a reference station and a rover station. The reference station includes a GPS receiver for determining a reference geographical location, a map converter for storing information for the parameter values for the radio regulations in one or more geographical regions and for converting the reference geographical location to the parameter values for the geographical region that encloses the location, and a reference radio for transmitting a radio message signal according to the parameter values.

Abstract: A method and system for determining the location of a mobile position determining system with respect to a destination. In one embodiment, a mobile position determining system has a communication device coupled thereto. Position information of the mobile position determining system is transmitted, via the communication device, to a destination position information database. The destination position information database contains position information of at least one destination. A position comparator then generates range and bearing information indicative of the relative position of the mobile position determining system with respect to the at least one destination. An output device then reports the relative position of the mobile position determining system with respect to the at least one destination to a user of the mobile position determining system.

Abstract: A system for tracking the location of, and for providing cellular telephone handoff for, a mobile cellphone user as the cellphone user moves from one cellzone to another. A boundary curve B12 between a first cellzone and an adjacent second cellzone is defined in an electronic map by an equation h.sub.B12 (x,y,z)-K12=0 for points with spatial location coordinates (x,y,z) lying on the curve B12, where K12 is a selected constant. First and second quasi-boundary curves QB1 and QB2, lying within the first and second cellzones, respectively, are defined, where each point on the curve QBi (i=1,2) lies at a selected distance di from the boundary curve B12. A region CR12 of points lying between the quasi-boundary curves QB1 and QB2 and including the boundary curve B12 is defined. The present location of the cellphone user is determined using a Satellite Positioning System (SATPS) such as GPS or GLONASS.

Abstract: The optimum design of the Satellite Positioning System Receiver is disclosed. The optimum design implementation of the receiver depends on the observed spectrum of the unknown W code of the satellite signals. In the preferred embodiment, the W code is synchronized with the C/A code EPOCH 1 and is not delayed. Both, the tracking and acquisition modes of operation are disclosed.

Abstract: The output phase measures output by a digital phase lock loop (DPLL) are selectively modified to reduce instantaneous phase errors incurred whilst waiting until the DPLL locks before obtaining an accurate phase measurement of a signal. In one embodiment, the output phase of a low bandwidth DPLL is selectively modified when the input signal exhibits a significant dynamic transient by adding the error term generated by the DPLL phase detector to the output signal generated by the DPLL to generate a modified output signal used to perform phase measurements.

Abstract: A global positioning system (GPS) receiver apparatus using time and frequency information derived from a radio signal other than the GPS satellite signal for improving the time to first fix (TTFF). The GPS receiver apparatus includes a GPS signal receiver for receiving a GPS satellite signal modulated with data bits and a radio signal receiver for receiving a radio signal having a standard time and/or a standard frequency. The radio signal receiver provides standard time information to the GPS signal receiver. The GPS signal receiver uses the standard time information to resolve a GPS time for a time of arrival of a data bit. The GPS signal receiver includes a propagation delay calibrator for correcting the standard time for the travel time due to the path length for the radio signal. The radio signal receiver uses a reference clock signal provided by the GPS signal receiver for determining a frequency error between a frequency of the reference clock signal and the standard frequency.

Abstract: A network comprises a plurality of GPS navigation receivers with two-way radio data communication for communicating the current computed positions of individual mobile units to other mobile units in the network and to stationary dispatch controllers connected in by the public switched telephone network. Ordinary telephone personal pager service is carried out transparently in the network for non-GPS equipped mobile units.

Abstract: A GPS/radio antenna for receiving a GPS satellite signal and a DGPS radio signal. The GPS/radio antenna includes a GPS antenna using a microstrip antenna element for receiving the GPS signal having GPS location determination information, a radio antenna for receiving a DGPS radio signal in the FM broadcast frequency range having DGPS corrections, an enclosure, and a cable. The GPS/radio antenna may be included in a GPS/DGPS receiver system also including a receiver unit with an FM DGPS receiver for demodulating the DGPS radio signal and providing DGPS corrections, and a differential-ready GPS receiver for providing a differentially-corrected GPS location.