NovAtel CORRECT™ with PPP
NovAtel’s Precise Point Positioning (PPP) algorithms combined with TerraStars precise GNSS satellite clock and orbit corrections delivers robust centimetre-level positioning globally. Corrections are delivered direct to the NovAtel receiver eliminating the need for additional cellular connectivity or base station.
- Optimized corrections and positioning solution
- Rapid re-convergence after GNSS outages
- Maintains positioning accuracy solution through correction outages of up to 5 minutes
- Scalable positioning accuracy levels to meet varied application needs
- Reliable positioning even in difficult environments
- Simplifies equipment needs by eliminating base station
- Sole source for GNSS hardware and corrections
About Precise Point Positioning (PPP)
PPP is a GNSS positioning technique that yields sub-metre-level or better positions by combining global GNSS satellite and signal corrections with GNSS receiver error modelling and position estimation algorithms.
The correction data required for a PPP solution includes GNSS satellite clock, orbit and signal-bias corrections generated from a network of global reference stations. Once the corrections are calculated, they are delivered to the end user over satellite- or the Internet. These corrections are used by NovAtel CORRECT on a dual-frequency OEM6 receiver, resulting in sub-metre-level or better positioning with no base station required.
A typical PPP solution requires a period of time to converge. This convergence period is necessary to estimate local measurement biases. The actual accuracy achieved and the convergence time required is dependent on the quality of the corrections, local-observing conditions, and the sophistication of the receiver algorithms.
If the PPP corrections and receiver algorithms are sufficiently advanced, then PPP ambiguity resolution is possible. Ambiguity resolution refers to the determination of the integer number of cycles in the ambiguous carrier-phase measurements. With the ambiguities resolved, the full accuracy of the carrier-phase measurement is unlocked. This, in turn, yields a corresponding improvement in solution accuracy. With a high-quality correction feed, such as that available through TerraStar, even RTK-level accuracies are possible. PPP ambiguity resolution also improves the ability of a PPP solution to recover following signal interruptions: without ambiguity resolution, there can be discontinuities and re-convergence periods in solutions following signal interruptions; with ambiguity resolution, solutions can instantly recover to full accuracy.
PPP ambiguity resolution is possible on NovAtel's OEM6 receivers with a TerraStar-C subscription.
Since PPP solutions are not dependent on a local reference receiver or network, users can achieve centimetre or sub-decimetre positioning in areas where it is not practical to use traditional RTK techniques. Delivery of the correction data over L-band satellite means any user who can see the satellite has access to corrections, making PPP an ideal solution for precision applications in areas where communications infrastructure is either unreliable or not available.
TerraStar Subscription Service Levels
Subscription-Based Services :
NovAtel’s vision is to solve position, anywhere, anytime. This can be particularly difficult when operating environments present challenges like tree lines or partial obstructions from buildings, or when traditional RTK infrastructure is unavailable. TerraStar correction services offered by NovAtel can help solve those tough positioning problems by delivering GNSS corrections via L-band frequencies to your receiver.
TerraStar Network Infrastructure:
Over 100 GNSS reference stations that are located around the world are operated, maintained and controlled by TerraStar. There are seven Geostationary communication satellites, which means two beams are always visible from anywhere on earth. The TerraStar network has three network control centres and backup to front line support is available 24 hours a day, seven days a week.
NovAtel offer high precision and broad accuracy solutions:
TerraStar-C (4 centimetre accuracy)
This high accuracy service is ideal for real-time pass-to-pass applications requiring centimetre-level repeatability and for high precision applications where no base station is available. Note: Starting July 1, 2019 customers with OEM7 products will no longer be able to purchase the standardTerraStar-C subscriptions.
Cuts initial convergence times by nearly 60 percent and offers 40 percent better horizontal accuracy than the standardTerraStar-C service with multi-constellation support, including the GPS, GLONASS, Galileo and BeiDou constellations. See TerraStar-C Pro product entry for more details.
TerraStar-L (40 centimetre accuracy)
For broad accuracy applications, TerraStar-L maximizes uptime and productivity. A real-time solution with fast initialization, it improves upon uncorrected positioning modes by providing a reliable decimetre position regardless of how challenging the operating environment.
Performance TerraStar-L TerraStar-C
Horizontal Accuracy (RMS) 40 cm 4 cm
Vertical Accuracy (RMS) 60 cm 6.5 cm
Convergence Time 5 min1 30-45 min2
1. Calculated from 7 day static data in Calgary. Accuracy will vary with observing conditions.
2. Convergence times dependent on observing conditions including number of visible GNSS signals, level of multipath and proximity to obstructions like large trees or buildings.