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A simple diagram showing the main difference between traditional navigation and RNAV methods. Area navigation (RNAV, usually pronounced as / ˈ ɑːr n æ v / "ar-nav") is a method of instrument flight rules (IFR) navigation that allows an aircraft to choose any course within a network of navigation beacons, rather than navigate directly to and from the beacons.
An example of this is the term "P-RNAV" (Precision RNAV) that Europe still uses (2019), which elsewhere is called "RNAV 1". The terms RNAV and RNP was earlier used with little functional difference. RNP required a certain level of performance but made no attempt to define how it was to be guaranteed. The two upper chart strips show the current ...
Area navigation (RNAV) and RNP systems are fundamentally similar. The key difference between them is the requirement for on-board performance monitoring and alerting. A navigation specification that includes a requirement for on-board navigation performance monitoring and alerting is referred to as an RNP specification.
The test statistic used is a function of the pseudorange measurement residual (the difference between the expected measurement and the observed measurement) and the amount of redundancy. The test statistic is compared with a threshold value, which is determined based on the requirements for the probability of false alarm (Pfa) and the expected ...
The US Nationwide Differential GPS System (NDGPS) was an augmentation system for users on U.S. land and waterways. It was replaced by [dubious – discuss] NASA's Global Differential GPS (GDGPS) system, which supports a wide range of GNSS networks beyond GPS. The same GDGPS system underlies WAAS and A-GNSS implementation in the US. [11]
GNSS-2 is the second generation of systems that independently provide a full civilian satellite navigation system, exemplified by the European Galileo positioning system. [5] These systems will provide the accuracy and integrity monitoring necessary for civil navigation; including aircraft.
Precise positioning is increasingly used in the fields including robotics, autonomous navigation, agriculture, construction, and mining. [2]The major weaknesses of PPP, compared with conventional consumer GNSS methods, are that it takes more processing power, it requires an outside ephemeris correction stream, and it takes some time (up to tens of minutes) to converge to full accuracy.
The receiver clock is then adjusted so its TOT matches the satellite TOT (which is known by the GPS message). By finding the clock offset, GNSS receivers are a source of time as well as position information. Computing the TOT is a practical difference between GNSSs and earlier TDOA multilateration systems, but is not a fundamental difference.