New SIT 185 Message Format

Summary

This video discusses updates to the C85 distress alert message format, which have been made to improve clarity and conciseness. Changes include the replacement of terminology like 'confirm position' with 'MCC reference position' and 'uncoded' with 'GNSS.' The reorganization of message fields ensures a more logical presentation of distress data, while redundant or unnecessary fields have been removed. The goal is to provide RCCs with a shorter, clearer message that retains all the essential data needed for efficient response. Detailed changes are available in CPASS documents A002 and G007.

Takeaways

• 😀 The C185 message format has been updated to improve clarity and conciseness in distress alert messages sent by MCCC to RCCs and spokes.
• 😀 The term 'confirm position' has been replaced with 'MCC reference position' to clarify the nature of the position data being provided.
• 😀 'Expected accuracy' has been changed to 'estimated error,' which now reflects the radius within which the position can be found with 95% probability.
• 😀 The term 'uncoded' has been replaced by 'GNSS' to specify that the position data is derived from Global Navigation Satellite Systems (GNSS) like GPS, Galileo, or GLONASS.
• 😀 The word 'confirmed' has been removed from the title of the C185 message to avoid confusion and make the message clearer.
• 😀 The message structure has been reorganized to improve the logical flow and categorization of distress data.
• 😀 The new format is shorter but still includes all essential information needed by RCCs for effective response.
• 😀 Fields with nil values have been omitted to reduce unnecessary clutter in the message, making it more concise.
• 😀 Unnecessary information, such as the 'next pass time,' has been removed from the message, as it is no longer relevant.
• 😀 Optional additional data can be included by MCCs, such as the satellite system used for position calculation and the number of packets received.
• 😀 Detailed descriptions of these changes are available in documents CPass A002 and G007, accessible on the Cassat website.

Q & A

What is the primary purpose of the C85 distress alert message?

The primary purpose of the C85 distress alert message is to provide critical distress and location information from a beacon (BON) to Rescue Coordination Centers (RCCs) and Mission Control Centers (MCCs), to assist in search and rescue operations.

What significant changes were made to the C85 message format?

The C85 message format was reorganized for clarity and conciseness. Key changes include replacing the term 'confirm position' with 'MCC reference position,' substituting 'expected accuracy' with 'estimated error,' and removing unnecessary fields. The message structure was also simplified into six main parts.

Why was the term 'confirm position' replaced with 'MCC reference position'?

The term 'confirm position' was causing confusion, as it implied that the position was the most accurate. The new term 'MCC reference position' more accurately reflects the position calculated by the MCC based on standard rules for calculation and position definition.

What does the term 'estimated error' now represent in the C85 message?

'Estimated error' now refers to the radius within which the beacon's position can be found with 95% probability. It replaces the previous term 'expected accuracy' to provide a clearer understanding of the uncertainty in the position data.

What is the significance of replacing 'uncoded' with 'GNSS' in the C85 message?

The term 'GNSS' (Global Navigation Satellite System) was introduced to clearly specify that the position information in the message comes from the beacon itself via satellite systems such as GPS, GLONASS, Galileo, or BeiDou, reducing ambiguity in the data source.

What are the six main sections of the reorganized C85 distress message?

The reorganized C85 distress message is divided into six main sections: 1) Message ID, 2) Beon Info, 3) 4D Location, 4) System Info, 5) Additional Info, and 6) Omitted or Empty Fields.

How does the new message structure improve clarity and conciseness?

The new structure improves clarity by organizing information into logical categories, eliminating redundant fields, and shortening the message. Unnecessary or nil-value fields are omitted, making the message more concise while retaining essential data for RCCs and MCCs.

What type of position information can be included in the '4D Location' field of the C85 message?

The '4D Location' field can include positions received from the beacon, such as GNSS positions, or calculated positions from other systems like Doppler, DOA (Direction of Arrival), or laser systems, providing a range of location data.

Why were some fields in the C85 message removed or omitted?

Some fields were removed or omitted because they were deemed unnecessary or no longer provided by the Cassat system. This reduces clutter and ensures that only the most relevant and accurate data is included, making the message clearer and shorter.

Where can more detailed information about the changes to the C85 message be found?

Detailed information about the changes to the C85 message can be found in Cassat documents A002 and G007, which are available for free on the Cassat website (46.org).