Abstract: An underwater remote sensing system comprising a transmitter for transmitting an electromagnetic signal, a receiver for receiving an electromagnetic signal reflected from an object and determining means for determining the location of the object, wherein at least one of the transmitter and receiver is underwater. The determining means may be operable to determine the location of the object using signals received at three or more receiver positions. To do this, three or more receiver antennas may be provided. Alternatively, a single receiver antenna may be provided and moved between three or more different measurement locations.

Abstract: A real-time in-situ sensor system is provided for measurement of bioluminescence and determination of bioluminescence surface signature. The system measures bioluminescence in the wake of a submerged moving object as well as ambient light levels outside of the wake. Along with measurements of depth and water-quality parameters including turbidity, temperature and salinity, the surface signature of the induced underwater bioluminescence can be calculated by considering light transmission and attenuation through water. With this real-time information, the operator of the submerged moving object can employ tactical maneuvers to affect the resultant surface signature.

Abstract: A sound collection environment deciding device for deciding whether the sound was collected in air or in water by utilizing an audio signal of collected sound is provided. Methods of Utilizing the audio signal of collected sound include, for instance, utilizing a difference of frequency characteristics between in-air and in-water of the audio signal of collected sound, utilizing a difference of propagation characteristics between in-air and in-water of the audio signal of collected sound, or the like.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A hydrophone for recording underwater sound includes a housing having an outer surface designed to serve as a boundary surface for an incident sound wave and at least one vibration sensor having a sensor surface for recording sound waves and for preparing a sensor signal. The sensor surface of the vibration sensor is in an opening of the housing. A hydrophone assembly includes a plurality of the hydrophones.

Abstract: This invention relates to immersed moving bodies for which the activity requires knowledge of their absolute geographic coordinates. This is the case particularly for moving bodies performing site survey operations, excavations and more generally exploration operations. A moving body can equally well refer to an independent diver, a manned vehicle or an unmanned machine. The device is used by an immersed moving body for independent determination of its absolute geographic coordinates. The device, according to the invention comprises on board calculation means (31) associated with “surface” position means (32) consisting of a GPS or GALILEO type receiver, submarine positioning means (33) operating on the principle of homing in association with immersed fixed acoustic beacon (41) and a set of sensors (36) that the moving body (42) uses to determine its working depth, its horizontality, and the difference between the direction followed and a fixed direction, for example magnetic north.

Abstract: A digital underwater acoustic sensor system is disclosed. The system can include an acoustic sensor configured to detect an underwater acoustic signal and form an analog signal proportional to the underwater acoustic signal. The acoustic sensor can include an interior cavity. A digital communication module can be positioned within the interior cavity. The digital communication module comprises an amplifier configured to amplify the analog signal. An analog to digital converter is configured to convert the analog signal to a digital signal. A digital signal transmission module is configured to communicate the digital signal to a receiver.

Abstract: A wireless communication system includes a transmitting device and a receiving device, in which the transmitting device generates a signal including information and transmits the signal by electromagnetic waves and ultrasonic waves in the same frequency in parallel, and in which the receiving device extracts the signal from at least one of the electromagnetic waves and the ultrasonic waves transmitted from the transmitting device and acquires the information included in the extracted signal.

Abstract: The present invention provides a communication device and a communication method of an underwater vehicle, which use an electromagnetic field (electromagnetic wave), having a higher propagation speed than that of an acoustic wave, for communication between an underwater vehicle and a mother vessel or the like so as to allow real-time control of the underwater vehicle and the like and further to make the communication little sensitive to noise and the like. The communication device performs wireless communication between an underwater vehicle in water and an object on land or on water, and is configured to compress data to be transmitted and transmit/receive the compressed data by the use of a low-frequency electromagnetic field.

Abstract: A method for communicating between marine vessels includes the steps of connecting a communication hub and a first marine vessel via a cable; transmitting an electronic signal via the cable between the communication hub and the first marine vessel; and transmitting the electronic signal wirelessly between the communication hub and a second marine vessel. The cable may be a seismic cable such as, and without limitation to, a streamer and an ocean bottom cable. The seismic cable may include one or more seismic sensors such as hydrophones and geophones.

Abstract: A very low frequency marine seismic source has a reservoir of water (47) feeding water to an aperture communicating with the surrounding water (13). The rate of water flow through the aperture is controlled by a rotor disc (11) and stator disc (9) having holes which overlap to a greater or lesser extent as the rotor rotates. The modulation of the flow of water produces a modulated pressure signal which is radiated into the surrounding water. The device is intended to produce acoustic signals over a band extending down to 0.5 Hz or lower.

Abstract: A navigation system extends satellite navigation to divers, underwater vehicles, and surface vessels. The navigation system comprises a location reference unit and a plurality of sub-surface beacon units. The location reference unit includes a receiver to receive navigation signals from earth-orbiting satellites and/or an inertial navigation system. The location reference unit further includes control circuits to communicate with to sub-surface beacon units and to transmit location information to said sub-surface beacon units, and a transceiver to transmit location information to the sub-surface beacon units. The beacon units include control circuits to determine the location of the beacon unit based on location information received from the location reference unit, and a transceiver to receive location information from the location reference unit and to transmit location information to a guided unit to provide navigation assistance to the guided unit.

Abstract: A system for three-dimensional tracking of high speed undersea projectiles may utilize a distributed field of randomly positioned passive acoustic sensors. The system measures variables related to the pressure field generated by a supercavitating projectile in flight wherein the amplitude of the pressure generated at a point in space is related to the projectile dimensions, velocity, and trajectory. The system iteratively processes data from the sensors to measure launch velocity, flight direction (trajectory), ballistic coefficient (drag), and/or maximum range.

Abstract: An acoustic underwater navigation system is disclosed. For instance, an underwater receiver determines its position using signals broadcast from an array of acoustic transmitters located near the surface. The position of the array is measured using global positioning system (GPS) technology and the transmitters collectively produce an acoustic signal in which the position and attitude of the array and the GPS time of transmission are encoded. An underwater receiver which is synchronized with the GPS time uses the transmitted position and attitude of the array and the transmission time information to calculate its position.

Abstract: A method of underwater communication between a link initiator and a link receptor, by transmitting a link acquisition waveform from the initiator to the receptor, and establishing communications channel parameters from such a received waveform. Data is then transmitted according to these parameters, which may include range, direction, frequency band and Doppler, with greater efficiency and robustness.

Abstract: Audio systems are housed by an enclosure with a substantially waterproof seal such that the audio systems may be mounted in outdoor locations such as decks, boat docks, and the like. The enclosure may include a panel that opens relative to a tub portion, such as by a hinged connection, and a substantially waterproof seal located there between. The audio systems may include one or more various features such as external speaker connections so that speakers may be located distantly from the enclosure. Other features may include internal amplification that may be stand-alone or integrated into an audio signal source such as a radio or compact disc player or combinational device such as an automobile head unit. Additional features may include a power supply that provides power for the amplification and/or audio source, an external cover with a substantially waterproof seal relative to the enclosure, filtered ventilation via an electric fan, and other related features.

Abstract: A robust underwater communication system, for communication between an acoustic signal transmitter and a remotely positioned acoustic signal receiver, wherein transmitted data is carried by a plurality of symbols each having two components one of which comprises a distinctive bit code and the other of which appertains to the character of the symbol as a whole wherein the character of successive symbols is stepped through a predetermined continuously repeating sequence of distinctive steps each of which occurs once in the sequence, the signal receiver being operated synchronously with the signal transmitter and comprising a correlator arrangement responsive both to the bit code and to the character of received signals for effecting demodulation and having a plurality of outputs one for each symbol, so that as each symbol is detected a signal on the output to which it corresponds pre-dominates and amplitude detector means responsive to the outputs from the correlator arrangement for providing an output signal c

Abstract: A portable diving apparatus, which comprises: (a) a water proof casing which comprises an external key pad; (b) a portable computing device within said water proof casing, said portable computing device comprises a diving module; (c) a pressure sensor which is mounted at least partially outside said water proof casing; (d) an adaptor within said water proof casing for receiving key pad entries from said key pad by means of first cable, and pressure indications from said pressure sensor by means of third cable, and for converting said key pad entries and said pressure indications to key pad data and pressure data respectively in a standard communication protocol, and transferring said data in said (wired or wireless) standard communication protocol into said portable computing device, wherein at least said pressure indications are processed by said diving module of said portable computing device and displayed as diver information on a display of said portable computing device.

Abstract: The present invention provides an underwater navigation system which can determine the bearing and the range of a remotely located beacon from a navigation station. The remotely located beacon transmits a pair of signals each having a different propagation velocity. Typically, the pair of signals are an acoustic signal and an electromagnetic signal. The range of the beacon to the navigation station is determined by a time differential in the detection of the two signals at the navigation station. The time differential is alternately a variation in phase between the two signals, or a time difference between the reception of a timing event encoded in synchronization on the pair of signals. In one form, the navigation station is a mobile unit which navigates to the remotely located beacon, and in another form the navigation station has a fixed position, and the remotely located beacon is mobile.

Abstract: A personal water safety device includes at least two sonar receivers, at least one water sensing device, and an alarm apparatus. The at least one water sensing device communicates with each of the at least two sonar receivers via sound waves. The alarm apparatus wirelessly communicates with each of the at least two sonar receivers. Each water sensing device is worn by a swimmer and is triggered to measure an elapsed time when the swimmer submerges in water, and transmits the measured time and a corresponding identification number to the at least two sonar receivers via the sound waves. The alarm apparatus receives the measured time and the corresponding identification number transmitted from each of the at least two sonar receivers, and generates an alarm when the measured time of one of the at least water sensing device exceeds a predetermined time limit.

Abstract: Advantageous online and/or real-time OFDM-based underwater acoustic (UWA) apparatus, systems and methods are provided according to the present disclosure. The apparatus, systems and methods employ a receiver with a bank of parallel branches, with each branch having a self-correlator matched to a different waveform scaling factor. A detection is declared when any of the branches leads to a correlation metric larger than a pre-defined threshold. The branch with the largest metric yields a Doppler scale estimate and a coarse synchronization point. The proposed apparatus, systems and methods use one OFDM preamble, thereby avoiding the need to buffer the whole data packet before data demodulation and enabling online and/or real-time operation. Thus, the disclosed apparatus, systems and methods are advantageously applicable to UWA communications.

Abstract: An underwater optical communications system and method particularly suitable for use in communications with automated equipment. A series of light beacons are dispersed throughout a communications zone. The light beacons are each provided with a plurality of light-emitting elements and light receiving elements which are positioned so that each beacon within the communications zone emits light in a plurality of directions and receives light from a plurality of directions. A submersible craft is similarly provided with light emitting elements and light receiving elements. The submersible craft is thus always in optical communication with one or more beacons when in the communications zone, regardless of the orientation of the craft and regardless of the position of the craft within the communications zone.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A counter-terrorism underwater surveillance system for detecting swimming intruders includes a sonar array 20 comprising a plurality of sensor elements which both transmit and receive acoustic signals. Power amplifiers 22 generate electric transmit signals which are converted to acoustic form for transmission by the sonar array 20. Incoming acoustic signals, including echo data from any intruder in the water, are received by the sonar array 20 and passed to a data acquisition subsystem 24, which digitises the data for processing. The digitised data is passed to a beamforming subsystem 26 which forms defined beams from omni-element data. A detection processing subsystem 28 then extracts signals from noise and reverberation and passes these to a display processing subsystem 30 which defines tracks from the intruder echo data. Finally, intruder images and tracks are displayed on a display subsystem 32.

Abstract: A system and method for relaying signals from a magneto-inductive system, which are normally used to communicate between magneto-inductive units using quasi-static magnetic fields, over a voice-band communication system. The magneto-inductive signals are modulated data signals having a carrier frequency typically between 300 Hz and 3 kHz. The voice-band communication system facilitates long distance communication of voice-band signals. By supplying the signals from one magneto-inductive unit to the voice-band communication system through an analog input port, the signals are transmitted through the voice-band communication system. They are output from the system through an analog audio output port to the other magneto-inductive unit.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: An underwater system (10) comprising a transmitter (12) for broadcasting an electromagnetic synchronisation signal and at least one node (14) that has a receiver for receiving that signal, the node being adapted to use the received signal for synchronisation.

Abstract: An extended underwater electromagnetic transducer is provided with an electrically insulated transmission line typically connected to a transmitter or receiver or transceiver system. The transmission line allows near-field communications with another transmitter or receiver or transceiver system. The transmission line provided is relatively long, the through water signal path length can be significantly reduced.

Abstract: A two-tier communication system for a seismic streamer. The communication system operates over an unshielded twisted-pair communication line extending the length of the streamer. Repeater units having a repeater function and a device controller function divide the twisted pair into line segments. Coils on each segment couple signals inductively to collocated external devices in a low-speed 2400 baud FSK data link between the devices and an associated device controller. A Gaussian 8-level FSK high-speed 60 kbit/s data link is established along all the segments with the repeaters re-transmitting boosted signals along the entire length of the communication line. The coils are transparent at the high-speed data rate. Time division multiple access (TDMA) or frequency division multiple access (FDMA) is used to accommodate the two links on the single twisted pair.

Abstract: A remote 3-D imaging system which uses a novel angular relationship to establish the relationship of the image features to the system, which is displayed by virtue of calculations. In addition to static surfaces, moving surfaces may be studied and corrections due to turbidity and platform position are also easily compensated for. A pre-test module is also included which predicts and has the ability to re-adjust the instrumentation to the test conditions as predicted by a hybrid Monte Carlo model. The instant system may also contain a plurality of sensing systems based on light, including traditional reflective or elastic scattering and novel fluorescent or non elastic scattering still and video imaging systems, including time-gated systems.

Abstract: A method for navigating underwater is disclosed. The method uses a navigation system to project a first velocity measurement along one or more signal beams having a second velocity measurement, where the second velocity measurement is related to at least one of the one or more signal beams. The method determines a position and location of an object associated with the navigation system based on a prediction of at least the second velocity measurement, and the navigation system is adjusted to perform within a prescribed measurement range based on a covariance of the first and second velocity measurements. The performance adjustments made in determining the position and location of the object are operable independent of the navigation system maintaining each of the signal beams due to one or more external environmental conditions.

Abstract: Methods and apparatuses process signals. The method according to one aspect of the present invention receives a first signal; obtains a second signal and a third signal from the first signal, wherein a gain of the second signal is smaller than a gain of the third signal; detects saturation in the third signal; and generates a composite signal from the second signal and the third signal, the step of generating a composite signal including selecting a part of the second signal for the composite signal, when the detecting step detects saturation in the third signal, and selecting a part of the third signal for the composite signal, when the detecting step does not detect saturation in the third signal.

Abstract: An underwater sounding apparatus includes a transmitter section (3) for transmitting an acoustic signal in a specific direction underwater from a ship, a receiver section (4) for receiving an echo reflected from inside a fish school FS as a result of the aforementioned transmitted acoustic signal by means of a receiving beam, and a signal processing section (5) for processing signals picked up by the aforementioned receiving beam. The signal processing section (5) calculates fish quantity information about the aforementioned fish school FS by integrating equivalent input sound intensities obtained by the aforementioned receiving beam in specific three-dimensional directions.

Abstract: A computer-implemented method, system, computer-readable medium, and apparatus for identifying a boundary of a cluster in a bitmap, the bitmap having at least one initially set bit, for applying an expansion shape to each of the initially set bits in the bitmap and identifying vertex bits on the boundary of the cluster formed by at least one expansion shape.

Abstract: A method of and system for monitoring the acoustic transmission conditions in underwater areas using an unmanned, mobile, submersible vehicle of the type including a source of acoustic signals. The submersible vehicle is controlled so that the vehicle traverses a desired path through the water of an area of interest. As the submersible vehicle traverses the desired path, a time-synchronized acoustic signal is transmitted from the acoustic source to at least one receiver spaced from the submersible vehicle so as to generate data representing the acoustic properties of the environment in the water between the acoustic source and the at least one receiver as the submersible vehicle traverses the desired path.

Abstract: Disclosed herein are systems and methods for providing wireless waterproof audio to a user in an aquatic environment. The systems may include earphones adapted to be waterproof and coupled to a receiver for receiving a wireless signal. The systems may also include a waterproof housing containing a transmitter and adapted to receive an electronic audio device such that the signal generated by the device may be transmitted by the transmitter.

Abstract: An acoustic Doppler system including an acoustic subsystem controller operatively connected to a plurality of acoustic transceivers, with a first of the plurality of acoustic transceivers, operating at a first acoustic frequency, operatively connected to a first group of at least one transducer, and a second of the plurality of acoustic transceivers, operating at a second acoustic frequency, operatively connected to a second group of at least one transducer, where the acoustic subsystem controller includes a digital circuit configured to sample analog signals received from the first and second groups of transducer in pairs having a pair-wise sampling frequency that is four times the operating frequency of associated acoustic transceiver.

Abstract: A waterproof casing includes a first casing having a first base wall and a first surrounding wall, and a second casing having a second base wall and a second surrounding wall. The first surrounding wall surrounds a periphery of the first base wall to cooperatively define a first receiving recess therewith, and has a first wall surface confronting the first receiving recess, and a first groove provided in the first wall surface. The second surrounding wall is connected to the second base wall proximate to the first surrounding wall to cooperatively define a second receiving recess therewith, and has a second wall surface outwardly of the second receiving recess, and a second groove provided in the second wall surface and corresponding to the first groove. A resilient member is fitted between and closes the first and second grooves. The first and second receiving recesses cooperatively receive a flat panel display.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: An underwater navigation system comprising a transmitter having an electrically insulted magnetic coupled antenna for transmitting an electromagnetic and/or magneto-inductive signal, a receiver having an electrically insulated magnetic coupled antenna for receiving an electromagnetic and/or magneto-inductive signal from the transmitter, and determining means for determining the position of the receiver relative to the transmitter using the received electromagnetic and/or magneto-inductive signal.

Abstract: A payload delivery unit for protecting and delivering a payload submerged in a submersion medium comprises a container including a pressure resistant shell and a resilient seal device. The shell defines a containment chamber and includes first and second shell members having opposed first and second sealing faces, respectively. The seal device engages and is interposed between the first and second sealing faces.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A passive listening acoustic system and method of use may include source means for providing continuous, pulsed, or pulse coded acoustic signals at two or more frequencies and at least two acoustic sensors or hydrophones which detect and record a signal for use within a Seabed Logging system to determine the position and/or orientation of instruments in the system.

Abstract: A diver unit computes the direction and distance to a specified target. When the target is obstructed, the diver unit receives navigation assistance data from another diver unit. The navigation assistance data includes direction information that is referenced to a common reference line extending between the two diver units.

Abstract: Signalling and localisation device for an individual in the sea, including an ultrasonic wave transmitter constituting an individual alarm unit carried by the individual in the sea designed to transmit carrier waves of primary signals; a surface surveillance means arranged on the surface of the sea and provided with: a submersed antenna capable of picking up the primary signals transmitted by individual alarm unit; means of transmitting secondary ultrasonic signals, these transmission means: means capable of calculating the position of individual alarm unit as a function of the ultrasonic signals received in response to secondary ultrasonic signals and of converting this information into the coordinates of a global positioning system; a unit for transmitting radio waves capable of sending signals representing these coordinates to a mobile or fixed alarm processing centre equipped with a radio receiver.

Abstract: A matched-field based sonar system and method of use that supports real-time, three-dimensional acoustic source localization using a mobile, horizontal array. The system receives and processes acoustic array, non-acoustic array, and own-ship navigational data in the matched-field process (MFP). Driven by own-ship and array status, a global bathymetry database and an acoustic environmental model are used to generate replicas for the MFP. If a three-dimensional tracker is assigned, then the tracker will steer the search region to maintain contact on the target of interest. Displays are provided to the user including tracker displays (which provide tracker information), MFP ambiguity surface displays (which support contact localization), and non-acoustic and navigational displays. A control interface allows a user to control the search region in bearing, range, depth, and frequency; assign the three-dimensional tracker function; and control display processing.

Abstract: An ultrasonic signal communication device that has an ultrasonic oscillation unit that has at least two resonance frequencies according to the oscillation mode, a transmission unit that generates a first ultrasonic signal at one of the two resonance frequencies and transmits the generated first ultrasonic signal from the ultrasonic oscillation unit, and a reception unit that receives from the ultrasonic oscillation unit a second ultrasonic signal that is transmitted at the other of the two resonance frequencies.

Abstract: The emergency underwater notification device disclosed, one of which would be carried by each diver on a team of divers at a dive site, comprises (a) an activator; (b) one or more primary signal emitters, each of which emits a primary notification signal upon activation of the activator, the primary signal emitter comprising one or more of the following: a light source, a hydrophone, a siren, a speaker, or an acoustic transducer; (c) one or more secondary signal emitters, each of the secondary signal emitters emitting a secondary communication signal upon activation of the activator; (d) a receiver capable of receiving communication signals; (e) one or more tertiary signal emitters, each of the tertiary signal emitters to emit a tertiary communication signal upon receipt by the receiver of either a secondary communication signal or a tertiary communication signal from another notification device; and (f) one or more quaternary signal emitters, each of the quaternary signal emitters to emit a quaternary notifi

Abstract: An underwater sound projector system comprises multiple sound projectors, each sound projector being capable of producing acoustic pressures. The sound projectors are held in close proximity such that the sound projectors interact with one another via the acoustic pressures produced. In embodiments, the number and/or spacing of the sound projectors are adjusted based on target performance parameters.

Abstract: A method for navigating underwater is disclosed. The method uses a navigation system to project a first velocity measurement along one or more signal beams having a second velocity measurement, where the second velocity measurement is related to at least one of the one or more signal beams. The method determines a position and location of an object associated with the navigation system based on a prediction of at least the second velocity measurement, and the navigation system is adjusted to perform within a prescribed measurement range based on a covariance of the first and second velocity measurements. The performance adjustments made in determining the position and location of the object are operable independent of the navigation system maintaining each of the signal beams due to one or more external environmental conditions.