What is BLADE?
Ashtech invests heavily in the development of cutting-edge technology to further strengthen its position as a leading designer and developer of precision positioning technology. Recent developments have produced greater product integration and progressive augmentations to GPS/GNSS. These advances are apparent in the latest line of professional products including the new Ashtech BLADE™ Technology.
BLADE: the Ultimate GNSS Technology
BLADE is Ashtech’s proprietary, state-of-art Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) and Differential GNSS (DGNSS) engine that is the core GNSS data processing technology in Ashtech’s Professional products. BLADE contains patented techniques for the optimal combination of different GNSS signals.
Most existing RTK engines were created as GPS (L1 only or L1&L2) engines. They were not initially designed to properly support other GNSS signals for each RTK-specific application. Adding other GNSS signals and specific functions to existing GPS-only source code may lead to non-optimal performance. BLADE was initially designed as a complete GNSS multiband engine (GPS+GLONASS+SBAS or other GNSS signals, L1&L2 or other bands) to support a very wide range of RTK applications from classic RTK/DGNSS rover against static Base/Network up to exotic applications like RTK against a moving base or attitude determination.
The universal and flexible implementation of BLADE allows Ashtech to use the same engine without any changes in different RTK products from L1 GPS+SBAS RTK (ProMark3 RTK) up to GPS+GLONASS+SBAS RTK (ProMark 500) and beyond. Thanks to the initial flexible design, BLADE can easily absorb all future incoming signals, such as GPS L2C and L5, GLONASS CDMA and L5 and Galileo. State-of-the-art coding allows the easy porting of BLADE to different platforms/OS. It can be used as the core of an OEM GNSS solution or as a separate RTK application running on 3rd party processors. The BLADE engine is also the core of Ashtech’s GNSS Solutions™ office software for data post processing. When used in post processing applications, BLADE can be run forward and backward many times to achieve post-processing performance that is better than real-time performance.
The Key Distinguishing Features of the BLADE Engine Include:
- Instant RTK
- Long Range RTK
- Effective RTK in shaded areas
- Float/Fixed and Flying™ RTK
- OTF ambiguity initialization as well as initialization with different geometric constraints
- GPS+GLONASS, GPS+SBAS and GPS+GLONASS+SBAS RTK
- L1 and L1+L2 RTK
- RTK against moving base
- Attitude determination functions, including self calibration
- Effective support of high update rate for both Time-Tagged and Fast RTK modes
- Robust performance with brief data link outages
- Built-in effective Network data (VRS, FKP, MAC) processing
- Supporting the entire range of RTCM-2, RTCM-3, CMR/CMR+ messages as well as Ashtech’s proprietary ATOM™ format
High-end BLADE performance is achieved not only by optimal processing of GNSS raw data (Ashtech and third party), but also with the proper usage of other available information (e.g. atmospheric parameters at base and rover).
How BLADE Benefits L1 Solutions:
The L1 GPS RTK solution from Ashtech allows SBAS measurements to be used in the RTK process, thus making it a true affordable GNSS technology. SBAS gives extra GPS-like measurements that improve satellite geometry and allow centimeter- level accuracy to be achieved faster than with the GPS only.
BLADE technology enables Ashtech L1 GPS RTK solutions to outperform other single-frequency RTK receivers. BLADE’s unique GPS+SBAS RTK algorithm ensures quick initialization with single frequency receivers and takes full advantage of the maximum satellite coverage from the dual constellation.
BLADE Benefits for Float RTK operations:
The goal of Float RTK is to insure position convergence to decimeter level. Float RTK never tries to fix the ambiguity, so there is no such thing as reliability. Usually, L1 RTK is float-ambiguity RTK, because single-band data (even with open sky and short baseline) cannot guarantee reliable and fast ambiguity fixing. The main disadvantage of Float RTK is the quite slow position convergence to decimeter level.
Thanks to BLADE, Ashtech has created a so called Flying RTK solution that enables improving the Float RTK performance of Ashtech receivers. BLADE improves standard Float RTK performance as it dramatically reduces the time of convergence, it enables Ashtech solution to reach the decimeter accuracy level quicker at a lower cost than competing systems.
BLADE Benefits with L1/L2 Multi-constellations Solutions:
A growing number of available satellites are providing significantly improved GNSS receiver performance in difficult satellite tracking conditions. However, GLONASS signal quality is not always stable. GNSS receivers must be able to overcome this instability to ensure high-quality RTK results. BLADE has the ability to provide the best possible measurements from three constellations – one of the key differentiators offered by the BLADE technology. BLADE itself makes all the checks and preparations needed to mitigate any negative effects of GLONASS signal instabilities. The result is more reliable measurement processing and usage than with competing board or GNSS receiver offerings.
Additionally, BLADE enables Ashtech GNSS boards and receivers to work with any other manufacturer’s base or reference stations by automatically measuring and removing the biases that are inherent with the Frequency Dependent Multiple Access (FDMA) technique used in GLONASS. The Ashtech Professional boards, sensors or complete receiver solutions with BLADE technology inside get the full benefit of any available GLONASS corrections