Analysis of GNSS Correction Data Standards for the Automotive Market

In the past few years, the number of applications for GNSS has grown dramatically. As a result of this progression, the requirements for GNSS positioning systems have also changed. One of the most relevant components in precision GNSS technology is the correction data format or standard used to transmit corrections from reference GNSS infrastructure to user GNSS receivers. These data can include corrections for GNSS satellite orbit and clocks, GNSS satellite equipment delays, and ionospheric and tropospheric refraction. With the introduction of high-precision GNSS technology into the automotive industry, it has become clear that an appropriate data correction standard does not exist, which is optimized to specifically serve this market segment. Such a standard requires low-bandwidth and at the same time must provide specific and detailed integrity measures for safety-of-life applications. In this paper, we present a new standard that has been developed by Sapcorda Services in order to target the specific requirements of the automotive sector. This new standard was created as a joint effort of several organizations and has similarities with RTCM v3; however, it has different message design rules, which allows for the use of low-bandwidth transmission. Results indicate significant reduction in bandwidth usage for the new format under various test scenarios, increased end-to-end positioning performance integrity, as well as, better flexibility for future growth of GNSS correction service technology capabilities.