Abstract: A cooperative location system for use with a Global Positioning System ("GPS"). The system includes a beacon that receives GPS signals and transmits GPS data representing the location of the beacon to a remote locator. The locator receives the beacon's GPS data from the beacon. Based on the beacon's GPS data, a reference direction provided by a compass, and the locator's own GPS data, the locator calculates range and direction information to the beacon.

Abstract: A pulse modulated amplifier is described comprising a power transistor having a grounded base, an emitter for receiving a drive signal to be amplified, and a collector for emitting a high frequency pulse, the power transistor operating over a substantially 360.degree. conduction angle variation during which the drive signal is amplified. The pulse modulated amplifier preferably includes a pulse modulator for generating a modulation drive voltage, and a current driver circuit responsive to the modulation drive voltage for generating a control current. The control current is applied to the emitter of the power transistor to control the output power of the emitted high frequency pulse. For a given drive signal the conduction angle of the power transistor is proportional to the control current, and for a given control current the conduction angle of the power transistor is inversely proportional to the drive signal.

Abstract: An RF pulse transmitter, for use in precision distance measuring equipment (DME/P) of a microwave landing system, includes appropriate circuitry to correct for incidental phase modulation (IPM). The pulse transmitter includes a modulation circuit for generating an RF pulse having a pulse peak. A reference phase control circuit is provided to generate a reference signal. A phase detector receives the RF pulse and the reference signal and in response thereto generates a phase error signal. The reference phase control circuit includes appropriate circuitry for adjusting the phase of the reference signal applied to the phase detector to thereby drive the phase error signal to a predetermined value at the pulse peak. A pre-distortion circuit generates a pre-modeled correction signal pulse for use in correcting for incidental phase modulation (IPM).