A method and means for enhancing the position accuracy of a civil or degraded accuracy GPS receiver by compensating for errors in its position solution with data derived from a military, or precise accuracy, GPS receiver, wherein the civil GPS receiver may be disposed in a mobile expendable vehicle and the military receiver in a mobile launch vehicle. The compensating data is obtained by a comparison of the pseudorange measurements of the military GPS set and another civil GPS set disposed with it in the launch vehicle and attached to the same antenna. Two embodiments are disclosed involving variations of calibration, 1) an On-the-Fly Relative Navigation technique, applicable when the expendable receiver tracks the same satellites as the military and civil sets are tracking, wherein the position bias determined from the measurements of the two launch sets is transferred to the expendable receiver and used to offset its solution, and 2) an On-the-Fly Differential Navigation system, used when the expendable receiver is not tracking the same satellites as the launch sets, wherein the correction process is performed relative to the military set's GPS position solution.
To cancel an error in GPS wave propagation time and calculate a relative position of a car running nearby to the own car position with good accuracy, a relative car positioning system using car communication includes a car communication transceiver, a GPS receiving device, a GPS information transmission/reception device, and a relative positioning device. A relative position is determined by determining a GPS wave propagation time difference from a GPS satellite, a wave of which is received by the car running nearby and the own car in common. The difference between the data of GPS wave propagation time at the car running nearby and the data of GPS wave propagation time at the own car is calculated, and if the number of differences of the GPS wave propagation time is obtained by more than three pieces, a relative position of the car running nearby is calculated by solving simultaneous equations expression the relative position as an unknown quantity.
A system for monitoring guiding and controlling an unmanned, unteathered flight vehicle, generally assumed to be moving through the earth's atmosphere at a high rate of speed. The system is comprised of on-board positional receiver and processing means coupled to a transceiver capable of combining such positional information with additional data relative to the health and status of the flight vehicle and transmitting the same to a ground station of compatible and simplified design. A preferred positional determination means is to utilize a form for GPS signal thereby affording one the opportunity to include appropriate processing software or additional componentry if necessary for base station purposes and thereby provide a relatively inexpensive system having a low probability of detection for intercept that simultaneously yields vastly improved operating performance characteristics over the mere translation of received GPS signals to down-link or to remote stations as known in the prior art.
A system for processing a PPS (precise positioning service) signal from a GPS (global positioning system) satellite to obtain PPS based positioning information therefrom. A first GPS receiver is adapted to process a PPS signal from a GPS satellite. The first GPS receiver is further adapted to output CVas (Crypto Variable Anti Spoofing) and SA correction information corresponding to the PPS signal. A second GPS receiver is adapted to receive the CVas and SA correction information from the first GPS receiver. The second GPS receiver is further adapted to process the PPS signal using the SA correction information received from the first GPS receiver and generate PPS based positioning information therefrom. The second GPS receiver does not include a KDP(key data processor). Accordingly, the second GPS receiver is not as tightly controlled as the first GPS receiver.
A system and method are provided for determining a position of a Global Positioning System (GPS) receiver prior to bit and frame synchronization. As such, the time-to-first-fix is substantially reduced. More specifically, pseudoranges to five GPS satellites are measured by correlating locally generated Pseudo-Random Number (PRN) codes with signals received from the GPS satellites. After correlation, the pseudorange measurements are correct with an unknown integer number of milliseconds error, which is different for each of the pseudorange measurements. Using the measurements of the pseudoranges and a mathematical model where each of the pseudorange measurements is forced to have a common channel time error, the user position and the common channel time error are determined prior to bit and frame synchronization.
A tail fin assembly for a munition having a housing configured for attachment to the munition, at least one flight control surface, an actuator for effecting movement of the flight control surface(s), so as to facilitate guiding of the munition, and a guidance system for controlling the actuator mechanism. The guidance system has a global positioning system (GPS) receiver for effecting control of the actuator mechanism.
